OBSTETRICS
Preconception Care
Preconception care is intended
to prevent congenital anomalies, maximize maternal health and is offered to all
women of childbearing age, since more than 50% of
pregnancies are unplanned.
- Proven benefits. Prevention of NTDs by
folic acid supplementation. Tight glucose control in DM results in lower
incidence of congenital abnormalities. Identify and when possible control
factors leading to previous poor results in pregnancy (such as preterm
labor from bacterial vaginosis, antiphospholipid antibody syndrome, etc.).
- Pre-pregnancy advice. Proper nutrition,
exercise, smoking cessation, abstinence from alcohol and drugs, protection
from radiation (x-rays) and workplace exposures, information on prescribed
and OTC drugs to avoid teratogenicity, infection control (STD protection
and treatment, rubella and hepatitis immunity status), and psychosocial
counseling for planning a pregnancy. Assess risk for congenital disease
(thalassemia, Tay-Sachs, cystic fibrosis, sickle cell, etc.).
Obstetrics: Prenatal Care
- History at Initial Evaluation.
- Menstrual history. Cycle length, age
of menarche, pain with menses, duration of flow, characteristics of
previous two menses, previous methods of contraception. Establish dates
carefully based on first day of last menstrual period and uterine size.
Obtain ultrasound if in doubt. Ultrasound dating is most accurate early
in the pregnancy.
- Medical history. Underlying problems or
illnesses, history of sexually transmitted diseases, medications, family
history, and genetic history.
- Habits. Tobacco, alcohol, other
recreational drugs, diet, activity, caffeine.
- Obstetric history. Dates of all
pregnancies including terminations and spontaneous abortions. Outcome and
gestational length. Duration and complications of labor. Particular note
should be made of previous shoulder dystocia, premature labor, premature
rupture of membranes (PROM), placenta previa, and postpartum hemorrhage.
The type of previous deliveries is also important: normal spontaneous
vaginal delivery (NSVD), forceps, C-section (indication, type of uterine
incision). Weight, sex, and Apgar scores of liveborn infants. Neonatal
complications. Number of living children.
- Social history. Occupational hazards,
support network, whether or not the father of child is involved, wanted
or unwanted pregnancy, expectations, potential stresses, need of social or financial services. Domestic
violence or sexual assault. See below.
- Prenatal Care for Patients at Risk for Preterm Labor. Frequent visits during weeks 22
to 32, cervical group B streptococci and urine culture at 24
weeks, vaginal exam for pH and cervical exam, monitor uterine activity,
education on nutrition and preterm labor, and reinforce what signs and
symptoms to watch for (abdominal cramping, pressure, cramps, backache,
increased vaginal discharge, fluid leak, regular uterine contractions).
- Physical Exam.
- General physical exam. Particular
attention to height, weight, BP, thyroid gland, dentition, heart,
breasts, deep tendon reflexes, signs of underlying heart disease.
- Pelvic examination.
- External.
Look for evidence of condylomata acuminata. These lesions may progress
during pregnancy, and a small percentage of infants born through
involved vaginal tissue will develop laryngeal papillomas or anogenital
warts. Podophyllin is contraindicated during pregnancy, but cryotherapy,
laser, and TCA may be used. Also look for and culture lesions suspicious
for herpes simplex.
- Vaginal and cervical. Look for evidence of condylomas and herpes. Examine vaginal
discharge and evaluate for Candida, Trichomonas, and bacterial
vaginosis (BV); culture cervical discharge for GC and Chlamydia.
Treat any vaginal infection. It is particularly important to screen for
and treat BV, since it is associated with an increased risk of preterm
labor, premature rupture of membranes, preterm birth, and histologic
chorioamnionitis. (See Chapter 13
for treatment.) Rule out cervical anomalies. Pap smear should be obtained
if patient has not had one in last 6 months.
- Bimanual.
Rule out adnexal abnormalities. Determine uterine size: 8
weeks = 2 x normal; 10
weeks = 3 x normal; 12
weeks = 4 x normal; 16
weeks = halfway to umbilicus; 20
weeks = at umbilicus; fundal height (weeks of gestation = cm from pubic
symphysis to fundus).
- Laboratory Evaluation at first prenatal visit.
- Routine. Pap smear, CBC, UA, and
culture to screen for bacteriuria, ABO blood type, Rh type, antibody
screen (indirect Coombs’), VDRL test, rubella antibody titer, and
hepatitis B surface antigen. Treat asymptomatic bacteriuria to prevent
pyelonephritis during pregnancy. Urine should also be screened for
protein and glucose by dipstick at each visit. Offer HIV testing. (Many
states require testing since AZT administered during pregnancy
substantially decreases risk of transmission of HIV to infant&endash;see Chapter 11.)
- When indicated. Cervical culture for GC
and Chlamydia, Toxoplasmosis antibody test, sickle cell
preparation, or hemoglobin electrophoresis in all previously unscreened
black women, tuberculin skin testing, HIV antibody testing, and CMV
titers.
- Labs During Pregnancy.
- Every visit. Dipstick urine for protein
and glucose.
- 15 to 20 weeks. Serum triple-screen
(alpha-fetoprotein [AFP], beta-HCG, and estradiol). See below.
- 14 to 20 weeks. Amniocentesis, when
indicated.
- 24 to 28 weeks. Blood glucose screen
after 50 g of oral glucose and urine culture.
- 28 to 32 weeks. Hematocrit
- 36 weeks. Rh antibody screening
if indicated. Consider GC, Chlamydia, and herpes rescreening in
high-risk women. Repeat hematocrit if indicated. Consider testing for
group B streptococci at 35 to 37
weeks (see recommendations below). Consider starting acyclovir for
patients with genital HSV which has been shown to decrease transmission
to the infant if given prophylactically.
- Expected Weight Gain.
- First trimester. Should gain 2 to 5 lb total.
- After first trimester. 3/4
to 1 lb per week.
- Average total weight gain.
25 ± 5 lb.
Obstetrics: Prenatal Patient Education
- Nutrition in Pregnancy.
- Caloric requirements. 30 to 35 kcal/kg/day
plus 300 kcal/day. Requirements are higher in adolescence and with multiple gestation.
- Calcium.
- Requirements.
1200 to 1500 mg of elemental calcium per day.
- Calcium supplements. Milk, 8 oz glass: 300
mg of calcium, yogurt; generic calcium carbonate (260
mg Ca/650 mg tablet);
calcium gluconate chewable (45
mg Ca/500 mg tablets; Tums
regular strength (200
mg Ca/500 mg chewable
tablet).
- Iron.
- Requirements.
30 mg of elemental
iron per day.
- Additional requirements. If the pregnant woman is iron deficient or has a
multiple-gestation pregnancy, she should take 60
to 100 mg of elemental
iron per day. If her Hb is <10,
she requires 200 mg/day.
- Iron supplements.
- Ferrous sulfate 65 mg of elemental Fe per 324 mg tablet (20% elemental iron).
- Ferrous fumarate 106 mg Fe/325 mg tablet (33% elemental iron).
- Ferrous gluconate 38 mg Fe/325 mg (11.6% elemental iron).
- Folic acid.
- Requirements.
0.4 mg to 1
mg/day. Most prescription prenatal vitamins contain 1
mg of folate. OTC prenatal vitamins contain 0.8
mg of folic acid.
- Sources.
Green leafy vegetables, broccoli, mushrooms, and liver.
- Adequate folate before conception has been
shown to reduce the risk of NTDs.
- Prior history of NTD or family history of NTD&endash;recommend 4
mg /day for 1 month before pregnancy
and during first 3
months gestation.
- Activity.
- Occupation.
Abstinence from physical work may be recommended if the woman has a
history of two previous premature deliveries, an incompetent cervix, or
fetal loss secondary to uterine anomalies. No controlled clinical trials
have demonstrated efficacy of bed rest for any of these conditions. Women
with premature rupture of membranes (PROM), CHF, hemoglobinopathies,
Marfan’s syndrome, or diabetes with multiple end-organ involvement are
also at risk for complications and may benefit from reduced activity as
can women with multiple gestations at over 28
weeks. Bed rest is indicated if there is a suspicion of IUGR,
preeclampsia, or preterm labor.
- Exercise.
(Expert opinion not controlled studies) Avoid in supine position after 1st
trimester. Avoid exercise with potential for abdominal trauma. Exercise
to fatigue not exhaustion. Contraindicated if pregnancy induced
hypertension (PIH), PROM, PTL (preterm labor), incompetent cervix,
vaginal bleeding, IUGR.
- Other.
There are no routine restrictions on sexual relations, other than comfort
and position. Caution should be used if any of the conditions listed
above apply.
- Habits and Miscellaneous.
- Alcohol.
Increases the risk of midtrimester abortion, mental retardation, behavior
and learning disorders. 10% to 30%
risk of fetal alcohol syndrome in offspring of women who drink 3
to 5 drinks per day. Risks with lesser consumption unknown.
- Tobacco.
Increases the risk of low-birth-weight infants, premature labor,
spontaneous abortions, stillbirth, and birth defects.
- Crack cocaine or other illicit drug use. Associated with perinatal addiction, preterm labor, and cognitive
and psychologic difficulties in the infant. Cocaine abuse during
pregnancy is associated with a significant increase in the incidence of
placental abruption.
- Caffeine.
100 mg/day or 1 cup of coffee (approximately 1 cup of coffee per day)
does not increase the risk of spontaneous abortions or IUGR.
- Seatbelts.
A seatbelt should be worn such that the belts do not directly cross the
gravid uterus; lap belt low over hips/ shoulder belt above uterus.
- Medications.
In general, no medications should be used without checking with a
physician.
- FDA classification of medication with regard
to adverse fetal effects. Category A:
proved safe for fetus in human studies (such as prenatal vitamins); Category
B: adverse effect not demonstrated in animal studies with no human
studies, or adverse effects shown in animal studies have not been
reproduced in human studies (as with penicillin); Category C: no
adequate animal or human studies are available, or animal studies show
adverse fetal effects with no human data; Category D: evidence of
fetal risk but benefits believed to outweigh the risks (as with
carbamazepine); Category X: drugs with proved fetal risks that
outweigh any benefits.
- It is recommended that you confirm the
category of all medications in pregnancy before prescribing or
recommending them to your patient.
- Drugs that are used in pregnancy with no
known adverse effect at the usual dose (some are class B). Antihistamines, decongestants (e.g., pseudoephedrine), some
antibiotics, (penicillin, ampicillin, cephalosporins, erythromycin),
non-quinine antimalarials, general anesthetics, acetaminophen,
tuberculostatics (INH, PAS, and rif-ampin), metronidazole (avoid in
first trimester if possible, though one study showed no teratogenicity),
steroids. Accidental use of clomiphene, bromocriptine,
birth control pills, and vaginal spermicides have shown no
adverse effects.
- Infections.
Avoid children with viral illnesses, especially if not rubella or CMV
immune. Avoid direct contact with cat litter and eating raw meat to
minimize contact with Toxoplasma gondii (toxoplasmosis).
- Domestic Violence
Screen all pregnant women for domestic violence. Violence often escalates
with pregnancy. Affects 0.9%-20%
of pregnant women in US. Ask direct questions, for example, "Have
you been hit, pushed or kicked in the last year?"
- Potential problems.
Advise patient to contact physician if she experiences vaginal bleeding,
leakage of fluid, fever, persistent nausea or vomiting, burning on
urination, severe abdominal pain, severe headache or visual disturbance,
persistent RUQ pain, peripheral edema, decrease in fetal movement.
(Generally after quickening, one should expect 4
or more fetal movements per hour or at least 10
discrete movements in 2 hours.)
Obstetrics: Rh Screening and Rho(D) Immunoglobulin
- Protocol for Routine Rh Screening and Administration of Rho(D)
Immunoglobulin.
- Initial visit.
Draw blood for ABO group, Rh type, and antibody screening (indirect
Coombs’).
- If patient is Rh negative. Repeat antibody screen at 26 weeks and, if no
antibody is detected, give 300 mg of Rho(D)
immunoglobulin (1 vial 5300 mg) IM. Can give Rho(D) immunoglobulin before knowing
antibody result. If antibody is detected, see "additional Rho(D)" below.
- After delivery.
Check fetal ABO/Rh type. If infant is Rh positive, mother receives 300 mg of Rho(D)
immunoglobulin IM within 72 hours of delivery.
- 1 vial suppresses immunity to approximately 30
ml of whole blood (15 ml of Rh(+)
packed RBCs).
- Additional Rho(D)
Immunoglobulin Requirements.
- If at anytime during pregnancy a
fetal-maternal hemorrhage is suspected, a Kleihauer-Betke (acid elution)
test should be performed. If positive, the mother should receive 10 mg of Rho(D)
immunoglobulin per milliliter of fetal blood calculated to have entered
the maternal circulation. However, the Kleihauer-Betke test is not 100%
sensitive, and so if there is trauma and a suggestion of fetal-maternal
hemorrhage, presumptive use of Rho (D) is indicated.
- A 50 mg dose of Rho (D) immunoglobulin (1
vial microdose = 50 mg) is indicated for an Rh-negative woman after
a first trimester terminated or spontaneously aborted pregnancy.
- A 300 mg dose of Rho(D) immunoglobulin is indicated for the
Rh- negative woman who undergoes amniocentesis, a spontaneous or induced
abortion, or who has an ectopic pregnancy.
- The Kleihauer-Betke test should be performed
after delivery if a larger than usual fetal-maternal hemorrhage may have
taken place, as with placental abruption. More than the standard 300 mg dose
may be required (which protects only up to 15
ml of Rh-positive red blood cells).
- Isoimmunization. If the patient is Rh
negative and the antibody screen is positive before Rho(D) immunoglobulin administration, obtain
an antibody titer and refer to a specialist. These infants are at risk for
erythro-blastosis fetalis.
Obstetrics: Prenatal Diagnosis of Congenital Disorders
- Overview. Major congenital
anomalies occur in 3% live born infants at
term and represent the leading cause of infant mortality in the United States. Family history should be obtained to evaluate the risk of
congenital disease. All women should be offered serum AFP/triple screen. A
patient’s attitude toward termination should not influence the
screening/counseling. Knowledge of fetal abnormality can facilitate
psychological adjustment and in the aid care of the fetus.
- Methods of Screening/Diagnosis.
- AFP/Triple screen. Offer to all pregnant women
at 15 to 20 weeks (see below).
- Chorionic villus sampling at 10
to 12 weeks (fetal loss rate of 0.5% to 1.5%).
No longer associated with increase in limb defects.
- Early amniocentesis performed between 12
and 15 weeks with 1% to 2% fetal loss rate.
- Midtrimester amniocentesis between 15
and 20 weeks with 0.5% to 1%
fetal loss rate.
- Fetal ultrasound
Obstetrics: Alpha-Fetoprotein (AFP)/Triple Screen
- Overview. The measurement of AFP,
estriol, and HCG (triple screen) in maternal serum at 15
to 20 weeks of gestation is used as a screening test for fetal structural
abnormalities and chromosomal abnormalities (trisomy 21).
All three levels are dependent on maternal weight and gestational age. Since
proper interpretation of AFP/HCG/estriol depends on fetal age, women with
abnormal values should be referred for ultrasound to confirm gestational
age and to evaluate for neural tube defects (NTD) and other structural
abnormalities. In the United States, the incidence of NTD is roughly 1
per 1000 live births.
- If Ultrasound Dating confirms the patient’s dates (i.e., the triple screen is abnormal) but no diagnostic structural
abnormalities are seen, the patient should be referred for amniocentesis.
- Risks. Psychologic stress, false positive results,
false reassurance, and potential fetal trauma secondary to amniocentesis.
- Causes of an elevated AFP.
- Underestimated gestational age.
- Open NTDs (meningomyelocele, anencephaly).
- Fetal nephrosis and cystic hygroma.
- Fetal GI obstruction, omphalocele,
gastroschisis.
- Prematurity, low birth weight, IUGR.
- Abdominal pregnancy.
- Multiple fetuses
- Fetal demise.
- Causes of a Low AFP.
- Overestimated gestational age.
- Missed abortions.
- Molar pregnancies.
- Chromosomal abnormalities (including Down
syndrome).
- Causes of a Low Estriol, Elevated HCG, and Low AFP: Trisomy 21 (Down syndrome).
Obstetrics: Antenatal Fetal Surveillance
- Obstetric Ultrasound.
- Indications.
Routine ultrasound is not indicated but can be used in the
following situations:
- To determine the presence or absence of an
intrauterine pregnancy.
- To determine gestational age.
- To measure fetal growth and identify
intrauterine growth retardation.
- To identify multiple-gestation pregnancies.
- To detect fetal anomalies (nearly 100%
sensitive for detection of NTD).
- To detect oligohydramnios or polyhydramnios
(if size greater or less than dates).
- To demonstrate placental abnormalities (e.g.,
abruption, placenta previa).
- To identify maternal uterine and pelvic
anomalies.
- Timing.
Will depend on the indication for ultrasound.
- In general, the earlier ultrasound is
performed in pregnancy, the more accurate is the EDC (first trimester
ultrasound gives EDC +/- 5
days; second trimester EDC + 10
days; third trimester EDC +/- 3
weeks). Fetal anomalies may not become apparent until after 20
weeks.
- Amniotic fluid volume and fetal movement,
tone, and breathing in conjunction with an NST can be used to calculate
scores on biophysical profiles (BPP, see below). This can be helpful in
the decision to induce or follow postdated pregnancies, high-risk
pregnancies, or diabetic pregnancies.
- Nonstress Testing (NST).
- Timing.
An NST should be done at the earliest point at which an intervention
would be performed if a clearly abnormal result were obtained (generally 32
to 34 weeks).
- Indications.
High-risk pregnancies including hypertension, diabetes mellitus, multiple
gestation, suspected oligohydramnios or IUGR, known placental
abnormality, maternal heart or renal disease, hemoglobinopathy, postdated
pregnancies, previous unexplained fetal demise and maternal perceptions
of decreased fetal movement.
- Equipment.
External fetal heart rate monitor and uterine contraction monitor.
- Interpretation.
- A reassuring NST
demonstrates three or more fetal movements accompanied by a fetal heart
rate acceleration of 15
beats per minute or more lasting at least 15
seconds during a 20-minute
period.
- Lack of fetal movement is non-diagnostic and a repeat NST should be performed after a meal. Lack of
movement for short periods of time may be attributable to fetal sleep.
However, absence of movement for prolonged periods of time may be
ominous.
- The NST is abnormal when the criteria for a reassuring NST are not met or late or variable
decelerations are present. A biophysical profile (BPP, below) is then
indicated.
- Biophysical Profile (BPP).
- Indications.
Same as for NST. May be used as early as 26
to 28 weeks for the surveillance of a complicated or high-risk pregnancy.
- Procedural details.
Real-time ultrasound coupled with external fetal heart rate and uterine
contraction monitoring.
- Interpretation.
Five parameters are evaluated: Fetal breathing movements; gross body
movements, fetal muscular tone, amniotic fluid volume (look for pocket of
amniotic fluid that measures 2 cm in two perpendicular
planes), reactivity of fetal heart rate.
- Each component of the BPP is given a score of
0 (parameter absent) or 2
(parameter present). The total score ranges from 0
(ominous) to 10 (reassuring;
infant at low risk of asphyxia). Further discussion of this topic is
beyond the scope of this chapter.
- Amniocentesis.
- Indications:
Done at 14 to 18 weeks of gestation to identify selected inherited disorders in
women at increased risk.
- Advanced maternal age (35 years of age or
older).
- Previous pregnancy resulting in the birth of a child with a chromosomal abnormality.
- Down syndrome or other chromosome abnormality in either parent or close family member or if either parent is a
carrier of a genetically transmitted disease (Duchenne’s muscular
dystrophy, hemophilia, metabolic disease, etc.).
- NTD
in either parent or a first-degree relative or previous child born with
a NTD.
- Abnormal serum AFP/triple screen.
- To detect isoimmunization
- Determine fetal lung maturity.
- Lecithin-to-sphingomyelin (L/S) ratio. If L/S is >2.0, there is a low risk of respiratory distress
secondary to prematurity.
- Phosphatidylglycerol (PG). PG first appears at 35 weeks gestation and increases in concentration until 40 weeks. If present, it provides reassurance of fetal lung
maturity.
Obstetrics: Group B Streptococcal (GBS) Infection
- Risk factors for Neonatal Sepsis.
Intrapartum chorioamnionitis, maternal group B streptococcal (GBS)
colonization in the rectum or vagina, prolonged rupture of membranes, and
prolonged monitoring with an internal pressure catheter or fetal scalp
lead.
- Vertical Transmission of GBS.
GBS is the number one cause of neonatal sepsis and meningitis in the United States. Infection occurs in 2 or 3
neonates per 1000 live births. Maternal colonization can be transient, and 20%
to 25% of pregnant females are carriers at any given time. In addition to
threatening the life of a neonate, GBS is also an important risk factor
for the development of chorioamnionitis in the mother, thereby increasing
morbidity and the rate of intrapartum complications.
- The CDC Recommends 2 Options for GBS.
- Option 1.
- Culture all women (rectal and vaginal) at 35-37
weeks. If the patient’s recto-vaginal cultures are
positive for GBS, she should be offered intrapartum antibiotic
prophylaxis.
- Treatment. Oral antibiotics are ineffective.
The following regimens may be used:
- Penicillin G 5 million units IV
and then 2.5 million units Q4h until delivery. Penicillin G is the preferred antibiotic because
of its narrow spectrum, making it less likely to select for
antibiotic-resistant bacteria.
- Ampicillin 2 g IV followed by 1 g Q4h until delivery.
- For penicillin allergy. Either clindamycin 900 mg IV Q8h or erythromycin 500 mg IV Q6h may be given
until delivery.
- Option 2. Screening cultures are not done, but antibiotic prophylaxis is
given if any of the following risk factors are present:
- Previously delivered neonate with GBS
infection.
- GBS bacteriuria
during the current pregnancy.
- Labor and delivery occur at less than 37 weeks of gestation (attack
rates for preterm infants are higher).
- Membranes
have been ruptured for >18
hours (12 hours in some
institutions).
- Intrapartum temperature greater than or equal to 38.0° C (100.4° F).
- If PROM occurs at <37 weeks of gestation and the patient is not yet laboring, GBS cultures should be collected as above. Either of the
following regimens may then be used:
- Give IV antibiotics until culture results are known, or
- Initiate antibiotic therapy only when
culture result confirms presence of GBS.
- Care of the infant of a mother who has had GBS prophylaxis.
- Any infant with symptoms or signs of GBS and
those infants born at less than 35 weeks gestation must have a full work-up (CBC, blood culture, CXR for pulmonary symptoms, LP if indicated).
They should be treated until culture results are negative.
- For those >35 weeks without symptoms, approach is
stratified based on duration of labor after the administration of
antibiotics.
- If duration of labor after antibiotics
is <4 hours, infant should have CBC, blood culture, and 48
hours of observation.
- If duration of labor after antibiotics is
>4 hours, observation for 48
hours is indicated.
Obstetrics: Nausea and Vomiting of Pregnancy
- Cause. Unknown. Probably not related to serum HCG
levels, but other hormones have been implicated (estradiol, thyroxine).
- Hyperemesis gravidarum. The incidence of
hyperemesis gravidarum (severe nausea and vomiting causing ketosis and
dehydration requiring hospitalization) is increased in multiple gestation
and molar pregnancies, and so ultrasound is advisable in cases of
hyperemesis gravidarum. Exclude organic causes: disorders of GI tract,
gallbladder, pancreas, hepatitis, and urinary infection. Recent data suggests
an association with Helicobacter pylori but this is not yet proven
and treatment for H. pylori is not yet standard of care. Elevation
of serum transaminase and mild jaundice can be observed, which will return
to normal after adequate hydration and nutrition. Hyperemesis gravidarum
has a 26% recurrence rate in subsequent pregnancies.
- Outpatient Management
- Reassurance
that condition improves with time, usually by end of first trimester.
- Avoid medications
whenever possible.
- Advise patient to
arise slowly and to keep soda crackers at the bedside and eat before
rising.
- Omit iron supplementation until nausea resolves.
- Eat frequent small meals and protein snacks at night.
- Antiemetics.
- Doxylamine succinate (Unisom) 25 mg 1/2
to 1 tablet PO Q am and Q
pm. This can be used in conjunction with pyridoxine.
- Diphenhydramine
(Benadryl) 25 to 50
mg PO Q6-8h.
- Phosphorylated carbohydrate (Naus-A-Way, Emetrol, Nausetrol) 15
to 30 ml PO
on arising and Q3h PRN for nausea.
- Meclizine
25 to 100
mg PO BID to QID.
- Pyridoxine
(vitamin B6) 25
mg PO TID.
- Bendectin
(10 mg of doxylamine
succinate and 10 mg of pyridoxine)
was removed from the market, although large studies have not shown
evidence of teratogenicity.
- Inpatient Management. For those with
severe symptoms, weight loss, dehydration, ketones in urine, or high urine
specific gravity. Correct hypovolemia, ketosis, and electrolyte imbalances
with IV fluids. Use oral fluids as tolerated.
- Monitor
fluid intake and output.
- Antiemetics
as above; also consider phenothiazines: prochlorperazine (Compazine),
droperidol (Inapsine) and promethazine (Phenergan).
- Parenteral nutrition for prolonged vomiting.
- Psychotherapeutic measures, stimulus control, biofeedback, and imagery can also be helpful.
Obstetrics: Diabetes in Pregnancy: Gestational Diabetes Mellitus (GDM)
- Potential morbidity.
- Infants born to diabetic mothers have 5
times the normal risk of respiratory distress syndrome, an increased risk
of congenital anomalies (especially with first trimester hyperglycemia), an increased risk of neonatal hypoglycemia,
hypocalcemia and jaundice.
- The mother has an increased incidence of
preeclampsia, infection, postpartum bleeding, and cesarean section (secondary
to macrosomia). There is also an increased risk of maternal injury during
vaginal delivery.
- Evaluation.
- Glucose challenge test (GCT).
- Timing.
A GCT is performed as a routine screen for GDM in all pregnancies at 24
to 28 weeks of
gestation. It should be performed earlier if symptoms are present or if
there is a previous pregnancy with GDM.
- If there are risk factors for GDM (e.g., massive obesity, prior history GDM), consider screening at
the first prenatal visit if there are risk factors. Repeat at 24
to 28 weeks if initial
test is negative.
- Procedure.
A blood glucose level is obtained 1
hour after a 50 g oral glucose
load.
- Interpretation.
A level of 140 mg/dl or greater
is abnormal. However, since there are many false positives, a 3-hour
fasting glucose tolerance test should be done if GCT is >130
mg/dl.
- Glucose tolerance test (GTT).
- Indication.
Follow-up of an abnormal GCT result.
- Procedure.
The patient must eat a diet containing at least 150
g of carbohydrate for 2
days. Draw a serum glucose level after an overnight fast. The patient
then ingests 100 g of glucose
solution. Serum glucose levels are then obtained at 1,
2, and 3
hours.
- Interpretation
(Table
14-1). If two or more of these readings are abnormal, the patient
needs treatment for GDM.
- Management of gestational diabetes.
- Dietary adjustment is the mainstay of therapy.
- Caloric intake should be 30 to 35 kcal/kg/day. Intake should be reduced to 24 kcal/kg/day if the patient is obese.
- Avoid cakes, candy, and other fast-acting
carbohydrates.
- Dietary composition should be 50% to 60% carbohydrate, 20% to 25% protein, and 20% fat, with high fiber content.
- Exercise has shown added benefit along with
dietary therapy.
- Obstetric surveillance.
- Early ultrasound for accurate gestational dating.
- Follow every 2 weeks until 36 weeks and then
weekly.
- Accucheck QID before meals and at bedtime.
- Check fasting blood glucose and review home monitoring at each visit.
If fasting glucose levels are >105 mg/dl (or postprandial values are 120 to 130), the patient may be hospitalized to ensure adherence to diet. If
fasting glucose remains >110 mg/dl, insulin therapy is indicated. Glyburide has been used
safely after the first trimester in patients failing insulin. However,
this is not the standard of care.
- Check for ketonuria daily to make sure there has been adequate caloric
consumption.
- Obtain an ultrasound if macrosomia is suspected. If the estimated
fetal weight is >4000 g, a cesarean section should be considered at term.
- Antepartum NST is often initiated on a weekly basis at 34 to 35 weeks of
gestation but may be started earlier. If euglycemia can be documented,
consider delaying monitoring until 38 weeks. Delivery is recommended if any sign of fetal compromise is
noted.
- Amniocentesis is helpful in documenting fetal lung maturity before cesarean
section, since infants of diabetic mothers have delayed lung maturity.
- Postpartum.
- Infants should be watched for evidence of
hypoglycemia due to high levels of
circulating insulin.
- Gestational diabetics should have a 75 g oral GTT checked 6 weeks postpartum to rule out persistent carbohydrate intolerance.
Counsel the patient that she has an approximate 35% risk of developing diabetes at some point in her life.
Obstetrics: Trauma and Pregnancy
- Differential. Retrospective study in
tertiary referral center showed etiology of trauma in pregnancy: 54%
motor vehicle accidents (MVA), 22% domestic violence, 21%
falls, 1.3% burn, puncture, or assault. Up to 50%
of falls cause some degree of abruption.
- Physical or Sexual Abuse. Abused women tend to present late for prenatal care. Generally
abuse continues and may worsen during pregnancy. Abused patients have an
increased risk for: preterm labor, chorioamnionitis and low birth weight
infants. Asking direct questions, such as "has anyone hit, slapped
or kicked you, etc," is the best way of screening for abuse.
- Management.
- Treatment of pregnant woman. ABC’s of evaluating and stabilizing mom take priority. Deflect
uterus away from great vessels by placing wedge under right hip or tilt
table laterally. Once the mother has been stabilized, consider fetus. If
mom is Rh negative, give RhoGam.
- Evaluation of fetus. Trauma increases the risk of placental abruption and fetomaternal
hemorrhage. Fetal monitoring and contraction monitoring is the best way
to assess for significant abruptio. Ultrasound is less sensitive and MRI
is not generally practical (although very sensitive). Monitoring for 2-6
hours is sufficient if no ominous signs (vaginal bleed, contractions, and
uterine tenderness) are noted. Make sure that the fetus has a good heart
rate and good beat to beat variability as well. If contractions are not
detected or occur less than every 10 minutes and
monitoring of the fetus is normal, an abruption unlikely. Twenty percent
of women with contractions greater than every 10
minutes have associated abruption.
- Return.
Women should be instructed to return for abdominal cramps, increasing
pain or vaginal bleeding.
Obstetrics: Hypertension in Pregnancy, Preeclampsia, and Eclampsia
- Pregnancy-Induced Hypertension (PIH).
- Definition. PIH is present when
diastolic BP >90 mm Hg or a
systolic BP >140 or a systolic
BP rises at least 30 mm Hg over baseline
value or diastolic BP rises at least 15
mm Hg over baseline value.
- Risk factors for PIH. First pregnancy,
multiple gestation, polyhydramnios, hydatidiform
mole, malnutrition, positive family history of PIH, underlying vascular
disease. Molar pregnancy should be expected if PIH occurs early in
gestation.
- Treatment. See section on
preeclampsia and chronic hypertension.
- Preeclampsia and Eclampsia.
- Preeclampsia. Defined as the presence
of hypertension or PIH accompanied by proteinuria, edema, or both after 20
weeks gestation. Preeclampsia is divided into mild and severe forms.
- Criteria for mild preeclampsia.
- Hypertension
as defined above but not meeting the criteria for severe preeclampsia
(below).
- Proteinuria
>300 mg/24
hours.
- Mild edema,
signaled by weight gain >2
lb/week or >6 lb/month.
- Urine output
>500 ml/24
hours.
- Criteria for severe preeclampsia.
- BP of greater than 160/110 on 2
occasions at least 6
hours apart with patient on bed rest or a systolic BP rise of greater
than 60 mm Hg over
baseline value or a diastolic BP rise of greater than 30
mm Hg over baseline value.
- The presence of an elevated blood pressure
and any of the systemic symptoms noted below categorizes the patient as
having severe preeclampsia regardless of the blood pressure.
- Proteinuria >5 g/24 hours or 31 or 41 on urine
dipstick.
- Massive edema.
- Oliguria <400 ml/24 hours.
- Systemic symptoms including pulmonary edema, headaches, visual
changes, right upper quadrant pain, elevated liver enzymes, or
thrombocytopenia.
- Presence of IUGR.
- Eclampsia: Occurrence of a seizure that is not attributable to other
causes in a preeclamptic patient.
- Evaluation of PIH and Preeclampsia.
- History. Document risk factors
and any symptoms outlined above.
- Physical. Look for evidence of
edema (particularly of the hands and face), BP changes, retinal changes, hyperreflexia, clonus, and RUQ tenderness.
- Initial laboratory studies.
- Blood: CBC
(elevated or normal Hb/HCT, low platelet count), electrolytes, BUN
and creatinine (creatinine >1.0
ng/ml, BUN >10 mg/dl, uric
acid (>5.5 ng/dl), liver
function tests (elevated AST, ALT, LDH), and coagulation studies
(elevated PT, PTT, and elevated fibrinogen degradation products).
Patients may also have hypo-albuminemia, as well as schistocytes
or helmet cells on peripheral smear from microangiopathic
hemolysis. If patient is in labor, send a blood type and screen.
- Uric acid (>5.5 ng/dl) may be elevated before there are other signs or symptoms of
preeclampsia.
- 24
hour urine for creatinine
clearance, total protein.
- Complications of Preeclampsia.
Eclamptic seizures; Hemolysis; Elevated Liver
function tests, Low Platelet count (HELLP) syndrome, hepatic
rupture, DIC, pulmonary edema, acute renal failure, placental abruption,
intrauterine fetal demise (IUFD), cerebral hemorrhage, cortical blindness,
retinal detachment.
- Management of PIH/Preeclampsia.
- Outpatient management. For
pregnancy-induced hypertension without significant proteinuria, home bed
rest is recommended. Home blood pressure monitoring, weight, and urine
protein checks are helpful. Antepartum surveillance (NST) should begin
early. Ultrasound exams should be performed periodically to ensure
adequate amniotic fluid and to monitor for intrauterine growth
retardation (IUGR).
- Hospital management.
- Indications. No improvement of mild pregnancy-induced-hypertension with home bedrest or
pre-eclampsia with 2+
proteinuria, evidence of organ system involvement.
- Orders.
Bed rest with bathroom privileges is allowed. The goal of IV fluids in
severe cases is to replace urine output and insensible losses.
- Laboratory evaluation and weights. Performed daily to every other day. Antepartum surveillance
including daily fetal movement count, daily NSTs, and weekly amniotic
fluid determinations by ultrasound is essential. Monitor symptoms such
as headache, visual disturbances, and epigastric pain.
- Delivery is treatment of choice. Delivery should be accomplished when the fetus is mature but may
be required early if maternal health is in danger or if there is
evidence of fetal distress. Delivery is indicated when the patient meets
criteria for severe preeclampsia. Betamethasone 12.5 mg IM should be given twice 24
hours apart to stimulate fetal lung maturation and can be repeated
weekly if pregnancy is prolonged. Electronic FHR monitoring during labor
is indicated.
- Antihypertensive therapy. Indicated only if BP persistently >160/110.
Aim for a diastolic BP 90
to 100 mm Hg. Avoid
overcorrection because normal blood pressures can result in placental
hypoperfusion.
- Diuretics and ACE inhibitor are
contraindicated during pregnancy.
- Acute management: Hydralazine IV 5 mg bolus and infusion
- Long-term medications (if the fetus is
immature) include methyldopa (Aldomet), atenolol, and labetalol.
- Anticonvulsant therapy. Seizure prophylaxis is indicated in all preeclamptic patients during labor and
delivery and for a minimum of 24
hours postpartum. Seizures may occur in the absence of hyperreflexia,
and increased DTRs may be present in the normal population; therefore,
hyperreflexia is not a useful predictor of who will have a seizure.
- Drug of choice for seizure prophylaxis:
Magnesium sulfate
- The loading dose is 4 to 6 g of magnesium sulfate IV over 20 minutes and continued at 2 g/hour.
- To treat active seizures. Magnesium sulfate 1 g/min IV until seizure controlled up to 4 to 6 g maximum. If this fails, see Chapter 2
for management of status epilepticus.
- Continue magnesium sulfate therapy at least 24 hours postpartum. In 25% of the patients postpartum eclampsia can occur. Monitor urine
output postpartum and stop therapy if urine output is >200 ml/hour for 4 consecutive hours. Watch for postpartum hemorrhage because
magnesium sulfate can relax the uterus.
- Managing magnesium therapy.
- Monitor urine output (100 ml in 4 hours), deep tendon
reflexes and serum levels. Therapeutic level is 4 mEq/L but since it takes 12 to 18 hours to
equilibrate, serum levels of magnesium sulfate are of dubious value.
- Magnesium toxicity. Loss of reflexes and drowsiness will herald
magnesium toxicity. At levels of 10 to 12 mEq/L and above, muscle weakness, respiratory
paralysis, and cardiac depression can occur.
- To treat magnesium toxicity. 10 ml of 10% calcium
gluconate (or calcium chloride) may be administered IV push in the
event of magnesium toxicity, or the magnesium infusion can be turned
off for 1 to 2 hours.
- Prevention of Preeclampsia.
Aspirin 81 mg a day and calcium supplementation have been used to prevent
preeclampsia. However, they have not been shown to be of any benefit in
controlled trials and do not change fetal or maternal outcomes.
- Chronic Hypertension Superimposed on Pregnancy.
- Risks.
- Maternal.
The risk to the mother is the same as in the non-pregnant state.
However, in the presence of superimposed preeclampsia (20%),
there is increased maternal mortality, frequently from intracranial
hemorrhage.
- Fetal.
There is an increased incidence of perinatal death, IUGR, and fetal
distress.
- Management.
- Treatment of chronic hypertension can decrease maternal and, to some extent, fetal morbidity.
Appropriate medications include methyldopa, hydralazine, and
beta-blockers.
- During pregnancy, it is not appropriate to
use:
- Sympathetic ganglion blockers (orthostatic
hypotension)
- Diuretics (aggravation of volume depletion)
- ACE inhibitors (associated with fetal
defects and neonatal renal failure)
- Laboratory evaluation is performed early in pregnancy.
- Obstetric visits
are scheduled every other week at 24
weeks and weekly after 30
weeks.
- Early ultrasound
is obtained for dating, and repeated periodically to look for evidence
of IUGR.
- Antenatal surveillance (NSTs) should begin at 34
weeks.
- Timing the delivery. The pregnancy should not be allowed to go beyond 40
weeks. Delivery may be required earlier if there is evidence of IUGR or
fetal distress or if hypertension cannot be controlled by bed rest and
medication.
- Intrapartum monitoring is required during labor.
- If there is evidence of IUGR, cesarean section is preferable to a prolonged induction.
- Complicated cases
or women with superimposed preeclampsia should be handled at an
appropriate referral center.
Obstetrics: Early Antepartum Hemorrhage
- Definition. Vaginal bleeding at <20
weeks of gestation.
- Differential Diagnosis of early vaginal bleeding.
- Spontaneous Abortion
- Incidence 15% to 25% of clinically recognized pregnancies end in a spontaneous abortion.
- Causes.
Fetal abnormalities incompatible with life (chromosomal and other),
defective implantation, maternal infection, uterine and cervical
anomalies.
- Evaluation
- History. Suggestive of pregnancy (missed period or periods, nausea,
vomiting, breast tenderness) followed by cramping and spotting or
bleeding often with passage of tissue. All patients should be evaluated
to rule out an ectopic pregnancy. Remember patients must be seen within
48 hours for RhoGAM
if indicated (i.e., mother is Rh negative)
- Exam. Including stability of vital signs, orthostatic vital signs,
pelvic exam looking for open or closed cervical os, tissue, other
causes of vaginal bleeding (such as cervical eversion, polyp,
infection, vaginal lesion, ectopic fetus). Size uterus. Check for fetal
heart tones with Doppler scanning if 10 to 12 weeks.
- Lab tests
- Urine pregnancy test is positive in 75% of cases so a negative pregnancy test does not
rule out spontaneous abortion.
- CBC, blood type, and antibody screen in all patients for Rh status. RhoGAM indicated
for all Rh-negative, antibody- negative
women.
- Uterine ultrasound or pathologic exam of tissue if indicated.
- Serial quantitative HCG should increase by at least 60% in 48 hours. If it does not rise or drops, it is likely that the
pregnancy is nonviable.
- Threatened abortion. Vaginal bleeding ± cramps but with a cervix that is long and
closed with a uterus appropriate for gestational age. Roughly 50%
progress to inevitable abortion.
- Inevitable abortion. Persistent cramps and moderate bleeding and a cervical os is open. Do not confuse with an incompetent cervix,
which is a painless cervical dilatation not associated with cramping and
is potentially treatable.
- Incomplete abortion. The same symptoms as an inevitable abortion but with some retained
products of conception in the uterus or cervical canal. There is ongoing
cramping and excessive vaginal bleeding. Speculum examination reveals a
dilated internal os and tissue present within the endocervical canal or
vagina. Bleeding may be heavy and clots may be mistaken for products of
conception.
- Complete abortion.
The entire conceptus is expelled and cramping and bleeding abate or
resolve completely. On examination, the uterus is firm, and smaller than
one would expect for gestational age.
- Missed abortion.
Products of conception retained 3 or more weeks after
fetal death. Signs and symptoms of pregnancy abate; pregnancy test
becomes negative. Brownish vaginal discharge (rarely frank bleeding)
occurs. Cramping is rare. The uterus is soft and irregular. Ultrasound
exam rules out live pregnancy.
- Septic abortion.
Any of the above scenarios and a temperature of greater than 38° C without other source of fever. Septic abortion is
associated with (but does not require) IUD use or instrumentation during
abortion. Abdominal and uterine tenderness are present as well as
purulent discharge and possibly shock.
- Ectopic Pregnancy.
See Chapter
13.
- Molar pregnancy
(hydatidiform mole). Placenta undergoes trophoblastic proliferation and
typically resembles a cluster of grapes. Occurs more often in women less
than 20 or greater than 40 years of age and almost
always causes some degree of vaginal bleeding. Hydatidiform moles are
associated with hyperemesis gravidarum and the onset of preeclampsia
before the third trimester. The uterus is larger than expected for
gestational age in 50% of the cases. Ovarian
enlargement may occur secondary to thecal lutein
cysts. Ultrasound findings typically show a "snowstorm"
pattern. Nearly 20% of hydatidiform moles progress to gestational trophoblastic tumor.
Treatment: Immediate evacuation of mole, subsequent follow-up for
detection of persistent trophoblastic proliferation or malignant change
- Treatment.
- Assure adequate circulating volume. Treat with IV normal saline or lactated Ringer’s. Consider
transfusion if Hb <8 g or patient is
unstable.
- Threatened abortion. Bed rest if possible; use acetaminophen for discomfort, nothing in
the vagina (no tampons, douches, intercourse), consider ultrasound for
gestational sac, cardiac activity, or to rule out ectopic pregnancy.
Positive cardiac activity predictive of continued pregnancy >90%.
Consider monitoring quantitative beta-hCG with a rise of less than 66%
in 48 hours predictive of abortion or ectopic.
- Incomplete or inevitable abortion. Hospitalize if hypovolemic, anemic, or advanced gestation >12
weeks. Tissue visible in os should be gently removed with ring forceps to
allow contraction of uterus; but minimize manipulation to decrease risk
of infection. Patients with incomplete abortion (tissue passed with
continued bleeding) often require suction curettage or D&C. Consider
oxytocin drip as an alternative (20 IU in 1000
ml of crystalloid solution at 50 to 100
ml/hour). If unsuccessful, proceed with D&C.
- Complete abortion.
Discharge home if vital signs stable, Hb documented to be stable, and
bleeding decreased. Consider methylergo-novine (Methergine) 0.2
mg PO TID for 3 days if diagnosis certain or after uterine evacuation.
- Missed abortion.
Obtain CBC with differential, platelet count, PT and PTT, and DIC (see Chapter 5)
panel if indicated. Outpatient management may be considered if retained
for less than 4 weeks, if weekly fibrinogen levels are obtained, and if
the patient is monitored closely for DIC. Hospitalize if there are signs
of infection, DIC, or if the fetus has been retained longer than 4 weeks.
Fibrinogen levels of less than 150 mg/dl call for immediate evacuation of
the uterus.
- Septic abortion.
Obtain CBC, UA, culture of discharge from uterus, blood cultures, chest
radiograph for diagnosis of septic emboli and to rule out free air from
perforation and abdominal radiograph to evaluate for uterine foreign
body. Electrolytes and ABG. Organisms include both anaerobes and aerobes
(Bacteroides, Streptococcus, Enterobacter, Chlamydia, Clostridium). Hospitalize, treat sepsis, D&C,
IV antibiotics:
- Doxycycline
plus cefoxitin or imipenem or ticarcillin, or
- Clindamycin
plus third-generation cephalosporin or gentamicin
- Discharge
to home with taking oral doxycycline or clindamycin.
- Long-Term Management Give RhoGAM to Rh-negative women. Provide emotional support.
Traditional but not well-founded recommendation is to wait 3
months before attempting conception. Having a single spontaneous abortion
does not increase the risk of aborting the next pregnancy. Evaluate
couple for habitual abortion if the woman has had two or more successive
spontaneous abortions. If the patient is a habitual aborter, obtain
antiphospholipid antibody titers. Obtain fetal tissue for karyotyping if
possible.
Obstetrics: Late Antepartum Hemorrhage
- Definition. Vaginal bleeding that
occurs after 20 weeks of gestation.
- Differential Diagnosis.
- Placenta previa.
- Incidence.
Occurs in 1 of 200
deliveries. The diagnosis of placenta previa is very common in the
second trimester, but more than 95%
of these do not have placenta previa at delivery.
- Classification.
Placenta previa may be marginal, partial, or total depending on how much
of the placenta is over the cervical os.
- Diagnosis.
Vaginal bleeding is typically bright red and painless. The blood loss is
not massive but tends to recur and become heavier as the pregnancy
progresses. Diagnosis may be made by ultrasound. The advisability of a
speculum exam is debatable. Digital examination is contraindicated other
than in a double setup situation when delivery is desirable and can be
rapidly accomplished by C-section. Maternal risk factors include
increasing age, multiparity, and prior uterine scar. Associated with
breech and transverse presentations.
- Placental abruption.
- Incidence.
Placental abruption occurs in 10%
of all deliveries. Severe abruption is rare.
- Classification.
- Mild. Slight vaginal bleeding (<100 ml), no FHR abnormalities are present; there is
no evidence of shock or coagulopathy.
- Moderate. Moderate vaginal bleeding (100 to 500 ml) and uterine hypersensitivity with or without elevated tone.
Mild shock and fetal distress may be present.
- Severe. Extensive vaginal bleeding (>500 ml), tetanic uterus, and moderate to profound
maternal shock are present. Fetal demise and maternal coagulopathy are
characteristic.
- Diagnosis.
The diagnosis of placental abruption is clinical. Although vaginal
bleeding is present in 80%
of cases, bleeding may be concealed in the remainder (that is,
retroplacental bleeding). Thus, the maternal hemodynamic situation may
not be explained by observed blood loss. Pain and increased uterine tone
are typically present. Risk factors include prior history of abruption,
maternal hypertension, cigarette or cocaine use, increasing maternal age
or multipar-ity. Abruption may be associated with premature rupture of
membranes, blunt abdominal trauma, and twin gestation after delivery of
first infant.
- Uterine rupture.
Very rare. May mimic severe abruption. An abdominal film may show free
intraperitoneal air or an abnormal fetal position. Accompanied by
persistent fetal bradycardia. Emergent C-section and hysterectomy are
required.
- Other.
Vasa previa (velamentous insertion of the cord). Delivery should be by
scheduled C-section. If pregnancy is allowed to progress to term,
spontaneous rupture of membrane or amniotomy should be averted because it
could lead to fatal bleeding for fetus and possibly mother. Cervical
dilation with loss of mucus plug may be confused with other causes of
vaginal bleeding or cervical or vaginal lesions (polyps, condylomas).
- Laboratory Evaluation should include a
CBC, type and cross, coagulation studies,
urinalysis, and ultrasound.
- Management of Placenta Previa and Placental Abruption.
- Placenta previa.
- If pregnancy 37
weeks or greater, or if fetal maturity has been documented, a cesarean
section is indicated unless only a minimal degree of placenta previa is
present.
- If bleeding is sufficient to jeopardize the
mother or fetus despite transfusion, cesarean section may be indicated
regardless of gestation.
- In the preterm gestation, expectant
management is indicated in patients with no observed bleeding, reactive
nonstress test and stable hematocrit, who are compliant with
instructions. Most patients require inpatient observation. Physical
activity is restricted. Nothing is allowed in the vagina, including
examining fingers. The hematocrit is maintained at 30%
or greater. Preterm labor can be managed with magnesium sulfate. Use of
beta-adrenergic agents can cause tachycardia and mask the signs of
bleeding. Once 36 to 37
weeks of gestation is reached with fetal maturity demonstrated by
amniocentesis, the patient is readied for elective double-setup
examination.
- Check for fetal bleeding: To 5
ml of tap water add 6
drops of 10% KOH in two test
tubes. Add 3 drops of maternal blood
to one tube and 3 drops of vaginal blood
to the other. The maternal blood will turn green yellowish brown after 2
minutes. If fetal red blood cells are present, the solution will turn
pink. Immediate delivery is indicated.
- Remember that placenta accreta may complicate
placenta previa in women with history of previous C-section. Hemorrhage
can necessitate hysterectomy.
- Placental abruption.
- Occasionally a small separation occurs
without further problem. These patients have no uterine symptoms.
Observation is required with fetal heart rate monitoring, serial labs
and ultrasound, but if no fetal distress occurs within the next 48
hours, the patient may be sent home.
- If placental abruption is mild and the fetus
is immature, expectant management may be indicated, with fetal heart
rate monitoring and serial laboratory and ultrasound examination.
- In all other cases, delivery is indicated. A
vaginal delivery is preferred when fetal distress is not present or when
the fetus is no longer viable. A C-section is indicated if fetal
distress is present. A C-section is also performed when there is a
threat to the mother’s life or a failed trial of labor.
- Shock must be treated with adequate
replacement of fluids and packed red blood cells; NS or LR should be
used. Urine output must be maintained at 25
to 30 ml/hour. A central
venous pressure line or Swan-Ganz catheter will assist in monitoring
hemodynamic status. See section on shock in Chapter 2.
- Coagulopathy should be treated with fresh
frozen plasma. One unit of FFP increases the fibrinogen concentration by
25 mg/dl. Platelet
transfusion is required if the count is less than 50,000. Heparin is not used in DIC secondary to placental abruption. See
section on DIC in Chapter 6.
Obstetrics: Intrauterine Growth Retardation (IUGR)
- Definition. IUGR is defined as a
fetus that weighs less than the tenth percentile for its gestational age.
- Symmetric IUGR (intrinsic): normal head circumference-to-abdominal circumference ratio, caused by genetic disease or fetal infection and
has a poor prognosis.
- Asymmetric IUGR (extrinsic): increased head circumference/abdominal circumference ratio, caused
by placental insufficiency; good prognosis with appropriate treatment.
- Risk Factors.
- Chronic maternal disease including chronic maternal hypertension, PIH, diabetes, cyanotic
heart disease, collagen vascular disease, severe maternal anemia, renal
disease, multifetal pregnancy, etc.
- Fetal genetic disorders or fetal malformations.
- Intrauterine
infections. Rubella, herpes, toxoplasmosis, syphilis, CMV.
- Previous history of small-for-gestational-age
baby, smoking, drug, or alcohol abuse.
- Abnormalities of the placenta or placental blood flow.
- Diagnosis. One should be suspicious
when the fundal height does not exhibit the predicted 1
cm/week growth between 20 and 36
weeks of gestation. A lag in fundal height by 4
cm mandates ultrasonographic evaluation; otherwise, consider ultrasound on
a clinical basis. Serial ultrasonic scanning may confirm the diagnosis.
- Management. The development of IUGR
makes the pregnancy high risk. Stillbirth, oligohydramnios, and
intrapartum fetal acidosis are common antepartum complications. Close
antepartum surveillance is required, and the decision about when to
deliver the infant is complex. Neonatal complications include persistent
fetal circulation, meconium aspiration syndrome, hypoxic ischemic
encephalopathy, hypoglycemia, hypocalcemia, hyperviscosity, and defective
temperature regulation. A perinatologist should manage these pregnancies.
Obstetrics: Labor
Introduction. This section is organized sequentially as events
happen during labor and delivery. It starts with the management of preterm
labor and postdate pregnancies. It then discusses the
stages and management of labor, as well as the induction of labor. Finally, it
discusses the delivery itself.
Preterm Labor
- Definition. Onset of regular
contractions between 20 and 37
weeks of gestation occurring at least every 10
minutes and lasting 30 seconds with cervical
change. Discrimination from "false labor" is difficult.
Postponement of treatment until cervical change occurs may lower the
chances of success.
- Causes. Frequently unknown. Several factors have been
associated with preterm labor.
- Maternal factors.
Infections (systemic, vaginal, urinary tract, amnionitis), uterine
anomalies, fibroids, retained IUD, cervical incompetence, overdistended
uterus (polyhydramnios, multiple gestation), rupture of membranes.
- Fetal factors.
Congenital anomalies, intrauterine death.
- Management.
- Initial examination.
- Estimate fetal weight and age by ultrasound if necessary.
- Document FHR and uterine activity with external monitoring.
- Pelvic examination. Attempt to limit to one examiner and use sterile technique. Rule
out ruptured membranes by looking for vaginal pooling of amniotic fluid
and by nitrazine paper testing (turns blue if amniotic fluid present)
and evaluate sample of fluid for ferning via microscope. Obtain cervical
cultures for group B streptococci and do rapid group B streptococci
antigen testing if available. If membranes are ruptured, one can used
pooled amniotic fluid to determine fetal maturity by looking at the L/S
ratio and PG levels; otherwise amniocentesis may be necessary.
- Obtain cath UA
and culture.
- Consider fibronectin test-swab of posterior vagina.
- Tocolysis.
- Contraindications.
Evidence of fetal distress, fetal anomalies, abruptio placentae,
placenta previa with heavy bleeding, severe maternal disease.
- Risks of treatment. If membranes are ruptured, there is increased risk of cord
prolapse and amnionitis. Fetal mortality is increased if labor is
suppressed when there is IUGR. Mother may experience tachycardia,
nervousness, or pulmonary edema secondary to medication.
- Tocolysis most likely will be ineffective if labor is well established or if the cervix is dilated to 4
cm or more. Preparation should be made to deliver in the optimal
setting. Up to now there have been no large-scale controlled clinical
trials demonstrating that tocolytics delay delivery.
- Beta-adrenergic receptor agonists may inhibit uterine contractility but only prolong gestation for
about 48 hours. To a large
extent, the goal of tocolysis is to arrest labor long enough for
exogenous steroids to stimulate fetal surfactant production so as to
prevent the pulmonary complications of preterm birth.
- Protocol.
- Bed rest in left lateral decubitus position. Effective alone in 50% of patients.
- Sedation (100 mg of secobarbital
or 50 mg of
hydroxyzine).
- Hydration, but avoid large boluses (should not exceed 500 ml).
- Antibiotics controversial. Do not use for >2 days, to limit incidence of resistance.
- FHR and uterine activity monitoring.
- Steroids accelerate fetal lung maturation (betamethasone or dexamethasone
12.5 mg IM Q24h for 48 hours).
- Drug therapy (tocolytics)
- Terbutaline. Infusion should be titrated on an individual basis so as
to maximize inhibition of uterine activity and minimize maternal side
effects. Alternative to infusion: 0.25 mg SQ Q20-60 min until
contractions have subsided. Continue 2.5 mg PO every 2 to 4 hours. Doses up
to 5.0 mg can be used.
- Magnesium sulfate. MgSO4 also decreases uterine contractility but is not useful
long-term. It can be an adjunct to terbutaline.
- Other. Prostaglandin synthetase inhibitors (such as indo-methacin),
calcium-channel blockers, aminophylline, and progesterone are under
investigation.
Premature Rupture of Membranes
(PROM)
- Definitions.
- "Premature" rupture of membranes occurs if there is a delay of greater than 1
hour until onset of labor.
- "Preterm premature" rupture of membranes occurs before 37
weeks of gestation.
- Diagnosis.
- History of fluid
gush per vagina. Urine can
sometimes be confused with the rupture of membranes.
- Sterile speculum exam.
- Exam will show
pooling of fluid in vaginal vault.
- pH determination. Amniotic fluid
typically turns nitrazine paper blue. Contamination with
vaginal-cervical mucus, blood, or urine may lead to false positives.
- Fern test.
Allow a sample of fluid to air dry on a glass or slide. Examination of
amniotic fluid under the microscope reveals a classical "fern"
pattern.
- Cervical digital examination increases risk
of chorioamnionitis! Evaluate cervix
visually with sterile speculum. Avoid digital exams if possible unless
patient is in labor and delivery is inevitable. Check for cord prolapse.
- Management.
- PROM at term.
Most sources recommend induction and delivery within a range of 24
to 36 hours after admission.
- Preterm PROM.
Fetal maturity must be considered. Manage expectantly until the fetus is
mature unless chorioamnionitis (see below), fetal distress develops, or
labor cannot be inhibited with tocolysis (see above). Positive cervical
cultures should be treated but do not necessitate induction without other
signs of chorioamnionitis or fetal distress. Follow maternal and fetal
vital signs, including temperature every 8
hours and WBC counts as indicated. Antibiotics have been shown to prolong
pregnancy. Randomized double blind placebo controlled study showed
decreased infant morbidity with antibiotic therapy (ampicillin and erythromycin).
- Deliver if amnionitis. Signs include maternal or fetal tachycardia, maternal fever,
uterine tenderness, foul cervical discharge, uterine contractions,
leukocytosis, and the presence of leukocytes or bacteria in amniotic
fluid.
Postdate Pregnancy
- Definitions.
- Prolonged pregnancy. Longer than 40 weeks of gestation.
- Postdate pregnancy.
Longer than 42 weeks.
- Postmature pregnancy. Longer than 42 weeks with evidence of
placental dysfunction.
- Etiology.
- Most common.
Error in estimating EDC.
- Risk factors.
History of prior prolonged gestation (50%
risk), older age, anencephaly, or fetal endocrinopathy.
- Potential Morbidity.
- Maternal.
- Birth trauma
secondary to macrosomic infant because of shoulder dystocia.
- Operative delivery, secondary infection and
hemorrhage are more common with
postdate pregnancies.
- Neonatal.
Meconium aspiration syndrome, polycythemia, hyperbilirubinemia,
hypoglycemia, and anoxic organ damage.
- Management: Delivery Should Be Accomplished by 42 Weeks.
- Antepartum fetal surveillance with NST and amniotic fluid index assessment should be done at 40
and 41 weeks and twice weekly thereafter.
- Indications for immediate delivery. Cervix is ripe, decreased amniotic fluid, large fetal size (abdominal
circumference), nonreactive NST, and presence of meconium in fluid.
Pregnancies complicated by hypertension and diabetes should be induced at
or near term.
- Induction of labor
can be preceded by cervical ripening using PGE2
gel or insert. PGE2 gel (1
mg placed intracervically) has been shown to decrease the amount of
oxytocin needed to establish labor and rate of cesarean section in
patients induced for medical indications before 41
weeks of gestation. Decreased amniotic fluid leading to variable decelerations
and meconium staining may be managed with amnioinfusion (see below).
Nasopharyngeal aspiration at the perineum and endotracheal aspiration
should be performed once the baby is born to prevent meconium aspiration.
Anticipate shoulder dystocia.
Vaginal Birth After Cesarean Section (VBAC)
- Definition. Attempted vaginal
delivery in a woman who has undergone previous cesarean section.
- Decision to Attempt VBAC.
- Advantages include
overall reduced morbidity, mortality and cost compared with elective
C-section. Additionally, many women prefer a vaginal delivery.
- Disadvantages include the requirement for closer intrapartum monitoring and a higher risk
of infection compared to an elective C-section if a C-section is
required.
- Contraindications include a history of previous classical, T-shaped, or unknown uterine
incision, multiple gestation, an estimated birth weight >4000
g, a non-vertex presentation or inadequate facilities or personnel for
emergency C-section.
- Probability of success. Depends primarily on the indication of the previous C-section. If
the primary C-section was for breech position, abruption, placenta
previa, cord accident, antepartum hemorrhage, hypertensive disorder, or
fetal distress, there is a 74% to 94%
rate of success. If the primary C-section was for cephalopelvic
disproportion (CPD) or failed induction, there is a 35%
to 77% rate of success.
- Risks. In addition to the usual risk of delivery,
other risks include:
- Uterine rupture.
Very rare. Incidence increased if prior C-section was classical.
- Cesarean section.
Increased risk of C-section morbidity relative to elective C-section.
- Management.
- Preparation.
- Type and screen for 2
units of packed cells; intravenous line should be inserted.
- The anesthesiologist, surgeon, and physician caring
for the newborn infant must be notified in advance and be available.
- Labor.
- Electronic fetal monitoring is recommended.
- Oxytocin
may be cautiously used to augment labor, and close monitoring of uterine
contractions (using intrauterine pressure catheter) is necessary. Oxytocin
must be titrated with great care in a VBAC.
- The same expectations of normal progression
during labor should be applied to patients with a prior C-section.
- An experienced physician should be in
attendance throughout labor and delivery.
- Postpartum.
Manual exploration of the uterus after delivery of the placenta is
indicated to assess scar integrity.
Evaluation of Labor (Box
14-1)
- Collect the information in Box
14-1 on admission to labor and delivery.
- Pelvic Exam.
- Inspection.
- Look for herpetic lesions, condylomas, and
lacerations.
- Speculum examination may reveal pooling of
vaginal fluid, consistent with rupture of membranes. A nitrazine paper
test or swab of vaginal fluid on a glass slide may be necessary to prove
the presence of amniotic fluid in the vagina. The basic pH of this fluid
will turn the nitrazine paper blue. Care must be taken to avoid the
cervical mucus, which is also basic and may give a false-positive test.
If an air-dried sample of fluid reveals a fern-like pattern, the
presence of amniotic fluid is confirmed.
- Palpation of the cervix.
- Dilatation of the cervical os. Dilatation may range from 0
to 10 cm.
- Effacement.
The degree of thinning of the cervix. The cervix may range from 3
cm long (thick or with no effacement) to paper thin (100%
effaced). In nulliparas effacement often precedes dilatation.
Simultaneous effacement and dilatation is seen in multiparas.
- Palpation of the presenting part.
- Identification. Head, foot, buttock, other.
- Station. Station is described as the relationship of the fetal presenting
part to the level of the ischial spines in the maternal pelvis. Station
may range from -3 to +3. Zero station
(engagement) occurs when the lower most presenting part is palpable at
the level of the ischial spines. Always assess station by both
abdominal method and pelvic method to avoid errors caused by caput.
- Position. Position is described as the orientation of the presenting part
in regard to the maternal pelvis. Vertex presentation with the occiput
positioned either to the right or left anteriorly is the most common.
Normal Labor and Labor
Dysfunction
- Normal Phases of Labor.
- Latent phase.
Slow rate of dilatation, <0.6 cm/hour.
- Active labor.
- Acceleration.
Dilatation rate >0.6
cm/hour.
- Maximum slope of dilatation. Cervix >5
cm or rate >1.2
cm/hour for nullipara and >1.5
cm/hour for multipara.
- Deceleration.
Cervix >9 cm, not completely
effaced.
- Problems with the Progression of Labor.
- Prolonged Latent Phase. Defined as >20 hours in nullipara; >14 hours in multipara.
Cause: unripe cervix, false labor, sedation, and uterine inertia. Management:
observation, need for oxytocin stimulation. Avoid amniotomy. Good
prognosis for vaginal delivery.
- Protracted Active Phase. Rate of dilatation: <1.2 cm/hour in nulli-para; <1.5 cm/hour in
multipara. Cause: fetal malpositions (occi- put posterior), CPD,
hypotonic uterine contractions, and anesthesia. Management:
oxytocin stimulation. 70% require C-section.
- Secondary Arrest of Cervical Dilatation. Cessation of dilatation for >2
hours. High incidence of CPD: frequently require a cesarean section.
- Failure of Descent.
Arrest of descent during second stage. High incidence of CPD: frequently
required cesarean section.
- Protracted Descent.
Nullipara <1 cm/hour; multipara <2 cm/hour. Causes include
CPD, full bladder, and macrosomia. Inadequate pushing because of
anesthesia can also cause this disorder.
- Precipitous Labor
>5 cm/hour dilatation in nullipara; >10
cm/hour in multipara. Complications: trauma to birth canal, fetal
distress, and postpartum hemorrhage.
Intrapartum Monitoring and
Management
- Fetal Heart Rate. Electronic fetal heart
rate monitoring may be performed by means of external Doppler, or direct
scalp lead when membranes are ruptured.
- Indications.
Meconium staining, use of oxytocin; delivery of an anticipated premature,
postmature, Rh-sensitized, or growth-retarded infant; medical
complications associated with uteroplacental insufficiency (hypertension,
diabetes, severe anemia, heart disease, renal disease), presence of
abnormal FHR by Doppler scanning, VBAC, other intrapartum obstetrical
complications (failure to progress, excessive vaginal bleeding).
- Fetal heart rate tracing interpretation.
- Baseline fetal heart rate.
- Normal 120 to 160 bpm.
- Tachycardia >160 bpm. Cause:
fetal hypoxia, maternal fever, maternal hyperthyroidism,
parasympatholytic or sympathomimetic drugs.
- Bradycardia <120 bpm. Cause:
fetal asphyxia, anesthetics, fetal cardiac conduction defect. Usually
benign if good variability is present.
- Variability.
- Short-term variability. Beat-to-beat variation is normally 5 to 10 bpm (reliably
assessed with only a scalp lead).
- Long-term variability. Waviness of the FHR tracing, which normally has
a frequency of 3 to 10 cycles/min and an amplitude of 10 to 25 bpm.
- Decreased variability. Variability may be decreased by fetal sleep
cycles, CNS depression secondary to hypoxia or drugs, parasympatholytic
agents, extreme prematurity, or congenital anomalies. Loss of
variability is associated with a high incidence of fetal acidosis and
low Apgar scores.
- Common periodic patterns.
- Accelerations. Reassuring if associated with fetal movement. May be
compensatory before or after deceleration.
- Early decelerations. Occur coincidentally with uterine contractions
and are associated with fetal head compression. These are vagally
mediated and not ominous when they occur late in labor. These start
early in the contraction phase, reach their lowest point at the peak of
the contraction, and return to baseline levels as the contraction
finishes. The FHR does not fall below 100 bpm.
- Late decelerations. Transient but repetitive deceleration of the
FHR observed to occur late in the contraction phase. Reaches its lowest
point after the acme of the contraction and returns to baseline rate
once the contraction is over. Late decelerations result from fetal
hypoxia, indicate uteroplacental insufficiency, and are always
considered ominous.
- Variable decelerations. Characterized by variable duration, timing in
relation to contraction and intensity. This is a reflex pattern,
typically secondary to umbilical cord compression. May benefit from
amnioinfusion. Poor prognostic signs are the following:
- Association with poor
FHR baseline variability.
- Lack of
pre-deceleration and post-deceleration accelerations.
- Slow return to
baseline or failure to return to baseline.
- Biphasic shape (W =
knot in cord).
- Prolonged decelerations. Isolated decelerations >120 seconds can be seen with maternal hypotension,
maternal hypoxia, tetanic contractions, prolapsed umbilical cord, fetal
scalp procedures (vagal), and paracervical or epidural anesthesia. A
prolonged deceleration after severe variable deceleration may signal
impending fetal demise.
- Management of abnormal FHR pattern or fetal
distress.
- Turn patient onto left side to alleviate vena cava compression.
- Discontinue intravenous oxytocin.
- Apply 100% oxygen to mother by face-mask.
- Correct maternal hypotension or hypertension.
- Vaginal examination to rule out prolapsed cord.
- Consider fetal scalp blood sampling for pH determination (Table
14-2).
- With decreased variability, consider fetal scalp stimulation. The return of
variability is reassuring. If tracing maintains poor variability,
consider points a to f above.
- With prolonged bradycardia unresponsive to other maneuvers or late
decelerations with worsening fetal acidosis (pH <7.20), consider delivery by C-section.
- Uterine Activity. May be determined by an
indirect (external) pressure monitor, or by an
intrauterine pressure transducer when more accurate estimations are
required.
- Contractility.
Effective contractions should have an amplitude
of 50 to 75 mm Hg, duration of 45 to 90
seconds, and frequency of every 3 to 5
minutes.
- Resting tone.
Spontaneous labor 5 to 10
mm Hg. Induced labor 15 to 20
mm Hg.
- Rhythmicity.
Presence of coupling or tripling may represent hyperstimulation.
- Configuration.
Typically bell shaped. May become rectangular during pushing. The area
under the curve when an internal transducer is used may be calculated to
determine the adequacy of uterine contractions.
- Fetal Stimulation. When the scalp is
stimulated and there is an acceleration of 15
bpm lasting 15 seconds, it denotes fetal pH value of 7.22
or greater. Reverse is not true. Obtain baseline fetal scalp pH in
meconium staining. Draw maternal venous blood simultaneously for
comparison. In the case of maternal fever do not rely on fetal scalp pH
because fetal compromise can occur with normal values.
Obstetrics: Amnioinfusion
- Definition. Amnioinfusion is a
procedure in which a physiologic solution (such as normal saline) is
infused into the uterine cavity to replace the amniotic fluid.
- Indications.
- Correcting variable decelerations because of
cord compression.
- Reduce fetal distress caused by meconium
staining of fluid (rule out concurrent signs of fetal
stress).
- Correction of oligohydramnios.
- Technique.
- Catheter.
Double-lumen catheter: expensive but helps monitor uterine contractions.
- Infusate.
Normal saline, lactated Ringer’s (like amniotic fluid).
- Temperature.
Room temperature fluid can cause fetal bradycardia if infused rapidly.
Body temperature is more physiologic.
- Methods.
Continuous infusion by gravity drainage or by infusion
pump 10 to 15 ml/min or intermittent infusion by gravity drainage (1
L over 20 to 30 minutes, repeat Q6h). Small risk of uterine
rupture if efflux of infusate blocked.
- Efficacy.
- Oligohydramnios.
Lower rate of C-section for fetal distress and higher umbilical artery pHs at birth compared to those in patients not
receiving amnioinfusion.
- Moderate to thick meconium. Decreased rate of operative delivery, increased average 1-minute
Apgar scores, less meconium aspirated from below neonate’s vocal cords,
and a lower incidence of meconium aspiration syndrome compared to that in
patients not treated with amnioinfusion.
Induction of Labor
- Indications and Contraindications.
- Indications.
Pregnancy-induced hypertension, premature rupture of membranes,
chorioamnionitis, postdate pregnancy, IUGR, isoimmunization, other
evidence of hostile intrauterine environment, diabetes mellitus, other
selected maternal diseases, fetal demise.
- Contraindications.
Placenta previa, cord presentation, floating presenting part, abnormal
fetal lie, active genital herpes, invasive cervical carcinoma, pelvic
structural deformities, prior classical uterine incision. Oxytocin
stimulation would be relatively contraindicated in conditions that
predispose to uterine rupture (high parity, advanced maternal age,
fetopelvic disproportion, uterine overdistension, prior uterine scar).
- Induction Methods. Assess the inducibility
of the cervix using Bishop score (Table
14-3). Determine route of induction.
- Amniotomy.
- Cervix should be dilated enough to allow
reaching the membranes with the amniotomy hook. The fetus should be
vertex (unless breech delivery is planned) with the presenting part well
engaged and well applied to the cervix. The umbilical cord should not be
palpable.
- Membranes are hooked, and a gentle tug should
cause release of amnionic fluid. Assess fluid for presence of meconium.
- Monitor fetal heart tones before and after the procedure.
- Risks:
cord prolapse, injury to fetal part (unlikely with amnio hook)
- Dinoprostone (PGE2)
- Indicated
for cervical ripening if Bishop score <5
(see Table
14-3)
- Cervidil
(10 mg dinoprostone).
Administer as vaginal insert. 1
dose. Monitor for 120
minutes postinsertion.
- Prepidil
(0.5 mg dinoprostone)
Administered intracervically. Mon- itor for 60-120
minutes. May repeat after 6
hours. No more than 3
doses in 24 hours.
- Risks.
Hyperstimulation and uterine rupture.
- Endpoint.
Bishops score of 8
or higher, strong uterine contractions or change in maternal/fetal
status.
- Misoprostol (PGE1)
- Currently not FDA-labelled for cervical
ripening but meta-analysis compared use of intravaginal misoprostol with
dinoprostone, oxytocin, and placebo. Lower rate of cesarean section,
higher incidence vaginal delivery within 24
hours, and reduced need for oxytocin augmentation.
- Most common dose 25-50
mg inserted every 4-6
hours up to 6-8
doses. Continuous fetal monitoring recommended for 3
hours after dose.
- Risks.
Hyperstimulation, possible increased meconium staining, uterine rupture
- Oxytocin administration.
- Can use to ripen cervix but often used after
one of the above methods of cervical ripening.
- Close monitoring
of the parturient and fetus is essential. Most hospitals have written
protocols available.
- Place 10 units of oxytocin in 1000 ml of D5NS
or D5LR. Begin with a
low dose of oxytocin: 0.5
to 2 mU
per minute. (Each milliliter of the above solution contains 10
mU.).
- Advancing dose.
Various protocols exist regarding the rate for increasing the dose and
the maximum dose. If little uterine response is observed, the dose can
be increased by 1 to 2 mU/min
every 30 minutes. Most
patients respond to rates of 20 mU/min
or less. The faster the increase, the more likely the risk of
hyperstimulation. The rate of administration is held steady when a good
labor pattern (contractions every 2
to 3 minutes lasting 60
to 90 seconds with an
intrauterine pressure of 50
to 60 mm Hg and a
resting tone of 10
to 15 mm Hg) is
achieved. Ideally you want 150
to 250 Montevideo units. Montevideo
units = Number of contractions/10
min x (Average peak of contraction - Average baseline of contraction).
- If at any point the fetal heart rate
indicates distress, the patient should be placed on her left side,
oxygen administered, and oxytocin discontinued. Reinstatement of
oxytocin drip requires reassessment of the situation
Obstetrics: Obstetric Anesthesia and Analgesia
- Overview. Pain during first stage
of labor is attributable to uterine contractions and cervical dilatation.
During the second stage, pain occurs from distension and stretching of
pelvic structures and the perineum. Pain is conducted along the
paracervical or inferior hypogastric plexus.
- Systemic Narcotics. Meperidine 25
mg IV or nalbuphine (Nubain) 10 mg IV are given early
during labor and usually avoided at or near delivery. Maternal
complications: nausea, vomiting, decreased gastric motility,
respiratory depression. Fetal complications: respiratory
depression, CNS depression, and impaired temperature regulation. Naloxone
(0.01 mg/kg) can be administered to depressed newborn as IV bolus for
counteracting the effect of narcotics. Naloxone may also be given IM.
- Local Anesthesia.
- Pudendal block.
Provides analgesia to vaginal introitus and perineum. Usually used in
second stage of labor. Technique is beyond the scope of this manual.
- Paracervical block.
Provides analgesia during active phase of labor. Blocks pain caused by
uterine contractions. Technique is beyond the scope of this manual.
- Lumbar epidural anesthesia.
- Associated with prolonged labor and an
increased risk of chorioamnionitis.
- Contraindications include maternal fever, preexisting CNS disease, severe hypertension,
hypotension, hypovolemia, and coagulopathy.
- Psychologic Methods of Pain Relief.
Lamaze classes aid in preparation; hypnosis, acupuncture, and biofeedback
are also used.
Obstetrics: Vaginal Delivery
- Normal Spontaneous Vaginal Delivery.
- Cardinal movements (for vertex presentation).
- Engagement.
Occurs late in pregnancy for primigravida, at the onset of labor for
multigravida.
- Flexion.
Of the neck so that the smallest diameter possible presents. If the neck
does not flex, it may actually extend during labor, producing a brow or
face presentation.
- Descent.
Progressive with thinning of the cervix and lower uterine segment.
Depends on the force of contractions and on pelvic and presenting part
configuration.
- Internal rotation. Occurs during descent. Vertex rotates from transverse to either
posterior or anterior position to pass the ischial spines.
- Extension.
Occurs as the head distends the perineum and the occiput passes beneath
the symphysis.
- External rotation.
Occurs after delivery of the head with the head rotating back to a
transverse position as the shoulders internally rotate to an
anteroposterior position.
- Management of vertex delivery.
- Preparations for delivery. Should be made when the presenting part begins to distend the
perineum, sooner for multigravida. (Local or pudendal anesthesia can be
administered at this time.) Episiotomy (if needed) is not performed
until delivery is imminent. Episiotomy likely increases the risk of
third- and fourth-degree tears.
- Delivery of the head.
- Controlled so that there is no forceful,
sudden expulsion that may produce injury. As the vertex appears beneath
the symphysis, the perineum is supported by direct pressure from a
draped hand over the coccygeal region (Ritgen’s maneuver). This will
protect the perineum and assist in extension of the head as the vertex
passes the symphysis.
- As the head is delivered, it will rotate to
a transverse position, at which time the baby should be checked for the
presence of umbilical cord about the neck. If present, it should be
gently slipped over the infant’s head (or double clamped and cut if
this cannot be done easily).
- The mouth and nose should be cleared of
secretions with a bulb syringe or DeLee suction trap.
- Delivery of the shoulders. Shoulders should be rotated to an AP position in the pelvic
outlet as the head externally rotates. Gentle traction downward on the
head will assist in bringing the anterior shoulder beneath the
symphysis. Gentle elevation of the infant head toward the symphysis will
release the posterior shoulder.
- Delivery of the body. The rest of the body will generally deliver spontaneously and
quickly after delivery of the shoulders. Care must be taken to control
the delivery of the body to prevent unnecessary injury.
- Immediate care of the infant. Includes double clamping and cutting of the umbilical cord. Do
not milk the cord. The clamp closest to the umbilicus should be just
distal to the skin or longer if anticipate a need for an umbilical line.
A clear airway must be assured and body temperature maintained by drying
and wrapping, placing under a radiant heater, or in skin-to-skin contact
with mother’s chest.
- Forceps delivery:
Forceps are generally used to shorten the second stage of labor when in
the best interest of the mother or the fetus. A fully dilated cervix and
experienced physician are required. Advantages must be weighed against
the increased risk of maternal lacerations.
- Indications.
- Prolonged second stage.
- Primigravida with
regional anesthesia >3 hours.
- Primigravida without
regional anesthesia >2 hours.
- Multigravida with
regional anesthesia >2 hours.
- Multigravida without
regional anesthesia >1 hour.
- Fetal distress.
- Maternal exhaustion.
- Requirements.
- Fetal head engaged and in vertex-face
presentation.
- Position of head known exactly.
- Membranes ruptured.
- Cervix fully dilated.
- No clinical evidence of cephalopelvic
disproportion.
- Definitions.
- Outlet forceps. The fetal scalp is visible at the introitus. The head is at or
on the perineum, and the sagittal suture is in the AP plane or rotated
up to 45 degrees.
- Low forceps. The leading point of the skull is at least at +2 station.
- Midforceps. The leading point of the skull is engaged but is above +2 station. (Midforceps delivery should be
attempted only in extreme situations while simultaneously preparing for
C-section.)
- Selection of forceps.
- Simpson. Good for primigravida with prolonged second stage (molded fetal
head).
- Elliot. Better if multigravida and if less molded fetal head.
- Tucker-McLane. Has sliding lock, good for asynclitic fetal head.
- Kielland. Has minimal pelvic curve, often used for rotation.
- Piper. Used in breech extractions.
- Vacuum Extraction
A safe, effective alternative to forceps delivery. A term, vertex fetus
is required. Delivery should not be one that will require rotation or
excessive traction. Prior scalp sampling is a contraindication.
- Advantages.
- Simpler to apply with fewer mistakes in
application.
- Less force applied to fetal head.
- Less anesthesia necessary (local anesthetic
may suffice).
- No increase in diameter of presenting head.
- Less maternal soft-tissue injury.
- Less fetal injury.
- Less parental concern.
- Disadvantages.
- Traction applied only during contractions.
- Proper traction necessary to avoid losing
vacuum.
- Possible longer delivery than with forceps.
- Small increase in incidence of
cephalohematomas.
- Technique.
- Ascertain that the cervix is fully dilated
and the head is in low or outlet position.
- The head is then wiped clean, the labia are
spread, and the cup is compressed and inserted. Pressure is applied
inward and downward until contact is made with the fetal scalp. The cup
should be placed over the posterior fontanelle.
- A finger is swept around the cup to make
sure no maternal tissue is within the cup. Suction pressure is raised
to 100 mm Hg, and the
location of the cup is rechecked.
- With the onset of a contraction, suction
pressure is raised to a range of 380 to 580 mm Hg. (Negative pressure should not exceed 600 mm Hg.) Traction is applied perpendicularly to
the cup, in line with the maternal axis.
- Should the cup be dislodged, the fetal scalp
is to be checked before the cup is reapplied.
- When the contraction subsides, the suction
pressure is reduced to 100 mm Hg.
- As the head crowns, an episiotomy may be cut
but likely increases the risk of third- and fourth-degree tears.
Traction is then changed to a 45-degree angle upward as the vertex clears the symphysis.
- Suction is released and the cup removed
after delivery of the fetal head.
- The procedure should be discontinued if one
fails to achieve extraction after 10 minutes at maximal pressure, extraction is not achieved within 30 minutes of initiation, the cup disengages three times, fetal
scalp trauma is sustained, or no progress is made after three pulls.
Obstetrics: Breech Delivery
- Overview.
- Incidence.
25% of all pregnancies <28 weeks of gestation, 3%
to 4% of all pregnancies at or beyond 34
weeks of gestation.
- Cause.
Low birth weight, placenta previa, uterine and fetal anomalies,
contracted pelvis, multiple fetuses all contribute to breech
presentations.
- Types of Breech.
- Frank.
Thighs and hips flexed, knees extended. 65%
of cases are frank.
- Complete.
Thighs and hips flexed, one or both knees flexed. 10%
of cases.
- Incomplete or footling. One or both thighs extended, one or both
knees below the buttocks. 25% of cases.
- Criteria for Vaginal Delivery of Breech Presentation. (Technique is beyond the scope of this manual.)
- Frank breech presentation.
- Fetal weight 2500
to 3800 g.
- Fetal head flexed.
- Gestational age at or beyond 36
weeks.
- Adequate maternal pelvis.
- No other maternal or fetal indicator for
C-section.
Obstetrics: Episiotomy
- Overview. A deliberate incision in
the perineum used to facilitate vaginal delivery. Stretching of the
vaginal tissues manually may prevent the need for episiotomy and minimize
the risk of tears.
- Midline. Good anatomic results,
easy repair, low incidence of postpartum pain or dyspareunia. However,
increases the risk of a third or fourth degree laceration compared to
patients without an episiotomy.
- Mediolateral. Less likely to extend through the sphincter but more likely to cause pain during healing, dyspareunia, or
excessive blood loss. Good anatomic results are more difficult to obtain.
Obstetrics: Shoulder Dystocia
- Incidence. Directly related to
fetal size: >2500 g 0.15%;
>4000 g 1.7%; >4500 g 10.0%.
- Diagnosis. Suspect shoulder dystocia
if there is reason to suspect macrosomia (gestational diabetes, history of
large infants, large maternal size, prolonged gestation), or if second
stage is prolonged. Consider C-section. In vaginal deliveries, suspect
dystocia if the head pulls back against the perineum after delivery, and external rotation is difficult.
- Management.
- Ensure adequate maternal anesthesia and cut a
very generous episiotomy.
- Attempt McRobert’s maneuver. The mother’s
thighs are hyperflexed, bringing her feet "to her ears." Have
an assistant apply suprapubic pressure. This causes the shoulder to move
under the symphysis pubis. Attempt delivery with gentle downward
traction.
- Attempt the Wood’s screw maneuver. Gently
rotate the posterior shoulder by pushing on the posterior scapula until
the shoulder passes under the symphysis and can be delivered as the
anterior shoulder.
- If this is unsuccessful, try delivering the
posterior arm first and then rotating the anterior shoulder into the
oblique position for delivery.
- If all else fails, one may attempt deliberate
fracture of the clavicle of the impacted shoulder. The thumb and
forefinger are used to push the clavicle outward to avoid a pneumothorax.
Although the fracture will heal, damage to cervical nerve roots may occur
and cause permanent sequelae.
Obstetrics: Cesarean Section
- Indications.
- Maternal and fetal.
Cephalopelvic disproportion, failed induction or progression of labor,
abnormal uterine contraction pattern.
- Maternal.
- Maternal diseases.
Eclampsia or preeclampsia with non-inducible cervix, diabetes mellitus
(if macrosomic infant precludes vaginal delivery), cardiac disease,
cervical cancer, active herpes genitalis. One double-blind clinical
trial showed that acyclovir suppression (400
mg PO TID) given after 36
weeks of gestation significantly reduces the need for cesarean section
by preventing a herpetic outbreak at term.
- Previous uterine surgery. Classic cesarean section, previous uterine rupture,
full-thickness myomectomy. If there is any question about the type of
incision made during a previous cesarean section, the operative report
for that delivery must be obtained so that incisional type can be known
with certainty.
- Obstruction to the birth canal. Fibroids, ovarian tumors.
- Fetal.
Fetal distress, cord prolapse, fetal malpresentations.
- Placental.
Placenta previa (unless marginal) and abruptio placentae.
- Risks.
- Maternal.
Infection, hemorrhage, injury to urinary tract, adverse reactions to
anesthesia, prolonged recovery.
- Fetal.
Depends on gestational age and indications for C-section. Less birth
trauma, though injury can be sustained during operative delivery. May
have increased incidence of respiratory distress syndrome.
- Antibiotic Prophylaxis. Reduced incidence
of endometritis, wound infection, urinary tract infection and fever
post-op with single dose of antibiotic (e.g., ceftriaxone, cefotetan)
prior to caesarean delivery.
Obstetrics: Postpartum Hemorrhage
- Definition. Postpartum hemorrhage is
most often defined as a blood loss greater than 500
ml in the first 24 hours after delivery. However, blood loss after spontaneous vaginal
delivery is frequently up to 600 ml and between 1
and 1.5 liters after instrumental or operative delivery. Therefore, clinical
experience is necessary to determine when bleeding is occurring too
rapidly, at the wrong time or is unresponsive to appropriate treatment.
Blood loss will be less well tolerated if the patient has not had the
normal expansion of blood volume during pregnancy, as in cases of preeclampsia.
- Risk Factors. Multiparity (>5
babies), previous postpartum hemorrhage, manual removal of the placenta,
placental abruption or placenta previa, polyhydramnios, prolonged labor,
precipitant labor, difficult forceps delivery, prolonged oxytocin administration,
breech extraction.
- Etiology. Uterine atony accounts
for most cases. Other causes include retained placenta, cervical or
vaginal tear, and coagulopathy.
- Physical Exam.
- Vital signs.
BP and pulse abnormalities are very late signs of bleeding due to
hemodynamics of pregnancy and usual young age of patient.
- Uterus should be palpated for evidence of atony, tenderness, or lack of involution.
- Vaginal exam
may reveal evidence of laceration (generally bright red blood) or atony
(darker blood). Bimanual exam may reveal mass (suggestive of broad
ligament or paravaginal hematoma).
- Hematocrit
is helpful only in comparison to the value before delivery. It will not
adequately reflect acute blood loss.
- Management.
- Reliable IV access
must be obtained with 2 large-bore IVs. Monitor
vital signs and maintain circulatory status with fluids. If the patient
shows evidence of symptomatic hypovolemia, blood should be sent for type
and cross. Coagulation profile should also be obtained.
- Review clinical course for probable cause (see predisposing factors listed above).
- Perform bimanual examination in recovery area or delivery room.
- Managing specific causes of postpartum
hemorrhage.
- Uterine atony:
- Uterine massage.
- Oxytocin IM (10-20 U)/IV (40 U/L at 250 ml/hr) if no contraindications.
- Methergine IM (0.2 mg ) contraindicated if hypertension, pre-eclampsia
hypersensitivity.
- Prostaglandin F2 (Hemabate) IM or intramyometrially 0.25 mg Q15 minutes up to 8 doses. Contraindicated if active cardiac, renal, pulmonary, or hepatic
disease.
- Retained placenta or invasive placenta. Manual removal of placenta, identify cleavage plain with
intrauterine hand, advance fingertips to separate. If can not identify
cleavage- probably invasive placenta and requires surgery.
- Trauma.
Identify laceration or hematoma and repair. Consider uterine inversion
and uterine rupture.
- If cause is not identified or fails to respond to the above measures, notify obstetric
physicians, anesthesia, and operating room personnel of potential need
for surgical intervention. Inform patient of the problem and what
measures are being taken to correct it. Get an appreciation of her
desires regarding further childbearing and hysterectomy.
- If uterine bleeding persists, surgery must be considered. Packing or balloon tamponade (e.g., 24
French Foley with 70-80
cc water) is a temporary measure and is rarely effective. Surgical
alternatives include uterine artery and hypogastric artery ligation.
Hysterectomy is the treatment of last resort when the patient desires
future fertility but may be preferred if sterility is desired.
Obstetrics: Postpartum Care
- Examples of Orders after Routine Vaginal Delivery.
- Immediately postpartum:
- Pitocin
10 units IM.
- Bed rest,
and vitals Q15 min for 1
hour postpartum.
- Ice pack
to perineum immediately postpartum PRN.
- Thereafter:
- Ambulate
as soon as possible.
- Diet.
General or other.
- Vital signs.
Q4h.
- Tucks
to perineum PRN.
- Sitz baths
TID and HS PRN.
- IV (if present).
Discontinue when vital signs are stable and uterine bleeding is normal.
- Bladder catheterization if unable to void in 6
to 8 hours.
- Breast binder
if not nursing.
- CBC
postpartum day 2.
- Administer Rho(D) immunoglobulin if indicated.
- Medications.
- Vitamins. Continue prenatal vitamins; additional FeSO4 if anemic.
- Pain. Acetaminophen 650 mg PO Q4-6h PRN or ibuprofen
400 to 600 mg PO Q4-6h for cramping
pain. Narcotics as needed (but be careful if breast feeding).
- Bowels. Docusate sodium 100 mg PO BID; milk of magnesia 30 ml PO QD PRN; bisacodyl 10 mg PO or PR PRN.
- Hospital Care.
- Physical examination.
- Monitor uterine changes. The fundus should be firm and at or below the umbilicus. Gradual
involution occurs over the next 6
weeks.
- Lochia
(uterine drainage) is initially red or bloody, gradually becoming
serosanguinous. By 2
to 3 weeks it should be
white. Tampons are contraindicated.
- Breasts
are examined for signs of infection and presence of milk. Colostrum is
present initially. Milk production should occur by the third to fifth
day in primiparas, sooner in multiparas. Breast feeding should not be
allowed for greater than 15
minutes on each side per feeding initially to help prevent soreness.
- Legs
should be examined for evidence of thrombophlebitis.
- Parent Education.
- Newborn care.
- Breast feeding
and prevention of lactation or engorgement if applicable.
- Discharge.
- Discharge instructions.
- Rubella vaccination, if indicated, before discharge.
- Instruct regarding signs of puerperal
infection, postpartum hemorrhage, and mastitis.
- Counsel on avoidance of intercourse and tampons for 4
weeks.
- Contraception counseling. OCPs can be started during week 4,
if desired. Low-dose or progestin-only pills and Depo-Provera have less influence
on lactation.
- Nutrition.
Especially if breast feeding.
- Medications.
Vitamins, iron, stool softener, when appropriate. Counsel on medications
to avoid during breast feeding.
- Discuss need for rest, possible stresses that can occur with new infant at home,
possibility of postpartum depression.
- Follow-up Exam.
- Postpartum check
at 4 to 6 weeks.
- Newborn checkup
typically at 1 to 2 weeks.
Obstetrics: Puerperal Fever
- Definition. Temperature >38.4° C in first 24 hours or >38.0° C for 2 consecutive days in the 9
days following delivery.
- Differential Diagnosis.
- Endometritis.
- Etiology. Polymicrobial with a mixture of
aerobic and anaerobic organisms. In particular, high fever within
the first 25 hours after
delivery may be caused by gram-negative sepsis, group B streptococcal
disease, clostridial sepsis, or toxic shock syndrome. Those 2
days to 6 weeks postpartum may be
secondary to Chlamydia.
- Risk factors.
C-section (20 times greater than
vaginal delivery), chorioamnionitis, prolonged rupture of membranes or
premature labor, multiple vaginal exams, retained products, manual
exploration of the uterus, low socioeconomic status.
- Treatment.
- Cultures of the cervix and blood may help
identify the causative organism, but treatment is often started empirically.
If Chlamydia is isolated or suspected based on late
presentation, add doxycycline or azithromycin to the regimen.
- There is no consensus on the safest and most
effective antibiotic regimens, only that it must have a broad spectrum.
Antibiotics are usually continued for 4 or 5 days and for 24 to 48 hours after
defervescence.
- "Gold standard" = Gentamicin (2 mg/kg IV loading dose, followed by 1.5 mg/kg IV Q8h) + Clindamycin (900 mg IV Q8h).
- Newer regimens (second- or third-generation
cephalosporins, semisynthetic penicillins).
- Cefoxitin 1 to 2 g IV Q6-8h.
- Ampicillin/sulbactam 1.5-3 g IV Q6h.
- If no response (maximum temperature not
dropping within 48 hours of initiation of therapy), start triple-agent therapy:
ampicillin and gentamicin and clindamycin, or ampicillin/sulbactam or
cefotoxin + ampicillin.
- Pelvic abscess.
Suspect if patient develops a pelvic mass or has persistent fever and
pain despite therapy for aerobic bacteria. Frequently develops 5
or more days after delivery. Must add therapy for anaerobic bacteria and
consider surgical or percutaneous drainage.
- Septic pelvic thrombophlebitis. Symptoms include spiking fevers with or without pain despite
antibiotic therapy. The patient may have a tender palpable mass. May have
a diagnostic response with improvement of symptoms after beginning
intravenous heparin and antibiotics. CT and MRI have been used to
diagnose this illness.
- Wound infection.
Presentation includes fever, a tender, erythematous, or fluctuant
incision, drainage of pus or blood. Usually occurs after the fifth
postoperative day. Risk factors include having an intrapartum cesarean
section; emergent abdominal delivery, use of electrocautery, placement of
open drains, obesity, and diabetes.
- Pulmonary atelectasis. See Chapter 15
for a discussion of pulmonary atelectasis and fever.
- Deep vein thrombosis. Symptoms include fever and lower extremity pain, swelling, and
pallor. Traumatic delivery, cesarean section, delay in the resumption of
ambulation, and varicose veins all increase likelihood for DVT formation.
See Chapter
4.
- Pyelonephritis.
Often accompanied by fever, malaise, flank pain, costovertebral angle
tenderness, and pyuria. Risk factors include occult bacteriuria, bladder
trauma, and Foley catheterization.
- Mastitis.
Suggested by fever and swollen, tender breast. Typically occurs 3
to 4 weeks after delivery. Breast feeding and contact with a carrier of Staphylococcus
aureus are the two prime risk factors.