INTRODUCTION

Background: Abruptio placentae is defined as premature separation of the placenta from the uterus. Clinically it most often presents with bleeding, uterine contractions, and fetal distress. It is a significant cause of third trimester bleeding and is associated with both fetal and maternal morbidity and mortality. It must be entertained as a diagnosis anytime third trimester bleeding is encountered.

Pathophysiology: As the placenta separates from the uterus, hemorrhage ensues into the decidua basalis. Vaginal bleeding usually follows, although it is possible to have a concealed hemorrhage where the blood pools behind the placenta.

If the bleeding continues, fetal and maternal distress may develop with fetal and then maternal death if appropriate interventions do not occur. The primary cause of placental abruption is unknown, but there are multiple risk factors that have been identified.

Frequency:
　

• In the US: Frequency of abruptio placentae in the US is approximately 1%.

Mortality/Morbidity: Maternal or fetal

The overall fetal mortality rate for placental abruption is between 20-40%, depending on the extent of the abruption. It is higher in patients with a significant smoking history. Fetal morbidity is caused by the insult of the abruption itself, as well as issues of prematurity.

Placental abruption is currently responsible for approximately 6% of maternal deaths. Maternal complications include:

• Cesarean delivery: Cesarean delivery is often necessary if the patient is remote from delivery or if there is significant fetal compromise. Typically, if there is significant placental separation, the fetal heart tracing will show evidence of fetal decelerations and even persistent fetal bradycardia.

• Hemorrhage/coagulopathy: Disseminated intravascular coagulation may occur as a sequela to placental abruption. Placental abruption is more at risk for developing a coagulopathic state than placental previa. The coagulopathy must be corrected to ensure adequate hemostasis in the case of a cesarean delivery.

• Prematurity: Delivery is the most important step in cases of severe abruption, even in the setting of profound prematurity. In some cases, immediate delivery is the only option even before administration of corticosteroid therapy in these premature infants. All other problems and complications associated with a premature infant are possible as well.

Race: Placental abruption is more common in African American women than in either Caucasian or Latin American women. However, it is unclear as to whether this is the result of socioeconomic, genetic, or a combination of such factors.

Sex: This is a disease observed only in pregnancy.

CLINICAL

History: Symptoms may include vaginal bleeding, contractions, abdominal tenderness, and decreased fetal movement. It is important to elicit any history of trauma, such as assault, abuse, or a motor vehicle accident. A quick review of the patient's prenatal course, such as a known history of a placenta previa, may help lead you to the correct diagnosis. Questioning the patient about symptoms of cocaine use, a history of hypertension or tobacco abuse is also important.

• Vaginal bleeding

• Vaginal bleeding is present in 80% of patients diagnosed with placental abruptions.

• Bleeding may be significant enough to cause both fetal and maternal jeopardy in a relatively short period of time.

• It is important to remember that 20% of abruptions can have a concealed hemorrhage and that the absence of vaginal bleeding does not rule out abruptio placentae as the diagnosis.

• Contractions/uterine tenderness

• Contractions or uterine hypertonus are part of the classic triad seen with placental abruption.

• Uterine activity is a sensitive marker of abruption, and in the absence of vaginal bleeding, should raise the suspicion of an abruption, especially following some form of trauma, or in a patient with multiple risk factors.

• Decreased fetal movement

• This may be the presenting complaint.

• Decreased fetal movement may be due to fetal jeopardy or death.

Physical: The physical examination for a patient who is bleeding is targeted at determining the origin of the hemorrhage. At the same time, it is imperative that the patient be stabilized quickly. With placental abruption the relatively stable patient may progress quickly to a state of hypovolemic shock.

• Vaginal bleeding

• Bleeding may be profuse.

• A fluid the color of port wine may be observed when the membranes are ruptured.

• Contractions/uterine tenderness

• Uterine contractions are a common finding with placental abruption.

• Contractions progress as the abruption progresses, and uterine hypertonus may be noted.

• Contractions are painful and palpable.

• Shock

• Patients may present with hypovolemic shock, with or without vaginal bleeding, as a concealed hemorrhage may be present.

• As with any hypovolemic condition, blood pressure drops as the pulse increases, urine output falls, and the patient progresses from an alert to an obtunded state as the condition worsens.

• Absence of fetal heart sounds: This finding occurs when the abruption has progressed to the point that the fetus has expired.

• Fetal jeopardy signs may include the following:

• Prolonged fetal bradycardia

• Repetitive late decelerations

• Decreased short-term variability

• Fundal height may increase rapidly, due to an expanding intrauterine hematoma.

• NOTE: Do not perform a digital examination on a pregnant patient with bleeding without first ascertaining the location of the placenta. A placenta previa first needs to be ruled out by ultrasound before a pelvic examination can be safely performed. If there is a placenta previa present, a pelvic examination either with a speculum or with a bimanual examination may initiate profuse bleeding.

Causes: While there are multiple risk factors for abruptio placentae, there are only a few events that have been closely linked to this condition, including:

• Cigarette smoking
• Cocaine (powder or crack) abuse
  　
• Trauma

Other notable risk factors include:

• Chorioamnionitis
• Prolonged rupture of membranes (24 hours or more)
• Preeclampsia
  　
• Hypertension
  　
• Maternal age of 35 and over
  　
• Male fetal gender
  　
• Low socioeconomic status
  　
• Previous abruption

• Cigarette smoking/tobacco abuse

• Cigarette smoking increases a patient's overall risk of placental abruption.

• A prospective cohort study showed the risk of abruption to be increased by 40% for each year of smoking prior to pregnancy.

• In addition to the increased risk of abruption caused by tobacco abuse, the perinatal mortality rate in infants born to women who smoke and have an abruption is increased as well.

• Cocaine

• The hypertension and increased levels of catecholamines caused by cocaine abuse is thought be responsible for a vasospasm in the uterine blood vessels that causes placental separation and abruption. However, this hypothesis has not been definitively proven.

• The incidence of abruption in patients abusing cocaine has been reported to be about 13 to 35%, and may be dose-dependent.

• Trauma

• Abdominal trauma is a major risk factor for placental abruption.

• Trauma may take the form of a motor vehicle accident. The lower seat belt should lie across the pelvis, not across the mid abdomen where the pregnancy is located.

• Trauma also may be due to domestic abuse or assault, both of which are underreported.

DIFFERENTIALS

Other Problems to be Considered:

Placenta previa
Preterm labor
Labor with bloody show
Vasa previa
Vaginal trauma
Malignancy (rare)

WORKUP

Lab Studies:
　

• No laboratory studies have been shown to definitively help with the differential diagnosis of abruptio placentae, but there are multiple labs that may be helpful in the management of this problem.

• Complete blood count (CBC)

• A CBC can help to determine the patient's current hemodynamic status but is not that reliable in estimating acute blood loss.

• In an acute hemorrhage the fall in hematocrit lags several hours behind, and may also be falsely decreased by the administration of crystalloid fluids during the resuscitation.

• Fibrinogen

• Pregnancy, by itself, is associated with hyperfibrinogenemia. Hence, modestly depressed fibrinogen levels may suggest significant coagulopathy.

• The goal should be to keep the level above 100 mg/dL with transfusion of fresh frozen plasma or cryoprecipitate, as necessary, to accomplish this.

• PT/aPTT

• Some form of DIC (disseminated intravascular coagulation) is present in as many as 20% of severe abruptions.

• As many of these patients may require a cesarean section for delivery, it is imperative to know the patient's coagulation status.

• BUN/creatinine

• The hypovolemic condition brought on by a significant abruption also impacts on renal function.

• The condition usually corrects itself without significant residual dysfunction, provided fluid resuscitation is timely and adequate.

• Kleihauer-Betke test

• This detects fetal red blood cells in the maternal circulation.

• If the abruption is significant, there may be inadvertent transfusion of fetal blood into the maternal circulation. In women who are Rh-negative, this fetal-to-maternal transfusion may lead to isoimmunization of the mother to Rh factor. A Kleihauer-Betke is helpful in determining the volume of fetal blood transfused into the maternal circulation.

• All patients who are D-negative should receive anti-D immunoglobulin (RhoGam) after significant trauma. The Kleihauer-Betke test may help determine the appropriate dosage of RhoGam in cases of large feto-maternal hemorrhage.

Imaging Studies:
　

• Ultrasound

• Ultrasound is a readily available and important imaging modality for bleeding in pregnancy.

• The quality and sensitivity of ultrasound to detect placental abruptions has improved significantly.

• Initially, fewer than 2% were diagnosed by ultrasound, but now more than 50% of patients with confirmed placental abruptions are identified.

• Ultrasound quickly helps to diagnose placenta previa as the etiology of bleeding if it is present.

• Placental abruption presents with retroplacental clot on the ultrasound. As a caveat, not all abruptions are sonographically detectable.

• In the acute phase, the hemorrhage is generally hyperechoic or even isoechoic when compared with the placenta and does not become hypoechoic for nearly a week.

Other Tests:
　

• Nonstress test

• Monitoring the fetus with external monitors often demonstrates fetal jeopardy, as evidenced by late decelerations or fetal bradycardia.

• An increase in the uterine resting tone also may be noticed, along with frequent contractions.

• Biophysical profile

• A biophysical profile (BPP) can be used to evaluate patients with chronic abruptions who are being conservatively managed.

• A BPP score less than 6 (maximum of 10) may be an early sign of fetal compromise.

  A modified BPP (NST with amniotic fluid index) also sometimes is used for monitoring in this situation.

Procedures:
　

• Ultrasound will help in ruling out other causes of third trimester bleeding. Possible findings consistent with an abruption include the following:

• Retroplacental clot (hyperechoic to isoechoic in the acute phase, changing to hypoechoic within a week)

• Concealed hemorrhage

• Expanding hemorrhage

Histologic Findings: After delivery of the placenta, a retroplacental clot may be seen. Another possible finding involves extravasation of blood into the myometrium, which produces a purple discoloration of the uterine serosa that is known as a Couvelaire uterus.

TREATMENT

Medical Care: Inpatient admission is required if abruptio placentae is suspected.

• Procedures are as follows:

• Obtain IV access with 2 large bore IVs.

  　

• Crystalloid fluid resuscitation of the patient.

• Type and crossmatch for blood.

  　

• Transfuse patient if hemodynamically unstable after fluid resuscitation.

  　

• Correct coagulopathy if present.

• Vaginal delivery

• This is the preferred method of delivery for a fetus that has died secondary to placental abruption.

  　

• It is dependent on the mother remaining hemodynamically stable.

• Delivery is usually rapid in these patients, secondary to the increased uterine tone and contractions that occur.

Surgical Care:

• Cesarean delivery

• Delivery by cesarean section is often necessary for both fetal and maternal stabilization.

• While this allows for rapid delivery and direct access to the uterus and its vasculature, it can be complicated by the patient's coagulation status.

• The type of uterine incision is dictated by the gestational age of the fetus, with a vertical or classical uterine incision often being necessary in the preterm patient.

• If hemorrhage cannot be controlled after delivery, a cesarean hysterectomy may be required to save the life of the patient.

• Before proceeding to hysterectomy other procedures, which include correction of coagulopathy, uterine artery ligation, administration of uterotonics if atony is present, and uterine packing, may be attempted.

Consultations:

• Maternal fetal medicine (MFM)

• If a mild abruption is diagnosed or there is a question about the diagnosis, a maternal fetal medicine (MFM) specialist should be consulted.

• In the case of a preterm fetus in whom tocolysis is considered, it is also prudent to consult a MFM specialist.

• Intensive care unit (ICU): If the patient is hemodynamically unstable, either before or after delivery, invasive monitoring may be required in the ICU.

Diet: The patient should be made NPO if emergent delivery is a possibility.

MEDICATION

Tocolysis is considered controversial in the management of placental abruption and is only considered in patients (1) who are hemodynamically stable, (2) in whom no evidence of fetal jeopardy exists, and (3) in whom a preterm fetus may benefit from corticosteroids or delay of delivery.

Even in patients with these criteria, consultation with a maternal fetal medicine (MFM) specialist is important. Tocolysis must be undertaken with caution as maternal or fetal distress can develop rapidly. In general, magnesium sulfate is used for tocolysis rather than beta-sympathomimetic agents. The latter has significant undesirable cardiovascular side effects in these patients.
　

Drug Category: Tocolytics -- Tocolytics may allow for effective administration of glucocorticoids to the preterm fetus to accelerate fetal lung maturation. In a chronic abruption, it may also allow for delay of delivery to a gestational age when complications of prematurity are less severe.

FOLLOW-UP

Further Inpatient Care:
　

• Admit for testing and possible delivery.

In/Out Patient Meds:
　

• Prenatal vitamins

• Iron supplements

• Stool softeners if the patient is hemodynamically stable and is kept as an inpatient for monitoring

Transfer:
　

• ICU transfer may be necessary before or after delivery if shock develops that requires invasive central monitoring or operative complications are encountered.

• Transfer to a facility with a neonatal intensive care unit (NICU) is needed if the fetus is preterm and appropriate facilities are not available. This should be accomplished after delivery if delivery is required to stabilize the mother.

Deterrence/Prevention:
　

• Elimination of correctable risk factors can decrease the risk of recurrence in subsequent pregnancies.

• Two of the most notable factors that can be corrected are smoking and cocaine abuse. Education about the risks of these behaviors as well as cessation or rehabilitation programs may help prevent future abruptions.

• If the patient was the victim of abuse, then preventing further abuse from occurring is an important consideration.

Complications:
　

• Fetal

• Death

• Issues of prematurity

• Maternal

• Death

• Transfusion-related morbidity

• Classical cesarean delivery with need for repeat cesarean deliveries.

• Hysterectomy

Prognosis:
　

• The risk of recurrence of abruptio placentae is between 4-12%.

Patient Education:
　

• It is important to educate patients about reversible risk factors, especially smoking, for any further pregnancies.

• Questions regarding possible trauma from abuse should also be asked.

MISCELLANEOUS

Medical/Legal Pitfalls:
　

• Failure to recognize signs and symptoms of abruptio placentae

• Failure to intervene in a timely manner

• As with any case in obstetrics there is always the possibility for litigation. Controversial decisions made regarding placental abruption, especially when tocolysis is considered, should be made in consultation with a maternal fetal medicine (MFM) specialist.