Evaluation of Fetal Death

Technically, the loss of a fetus at any stage is a fetal demise. However, in an attempt to separate early pregnancy loss (ie, spontaneous abortion) from later pregnancy loss, both the World Health Organization (WHO) and the American College of Obstetricians and Gynecologists (ACOG) recommend that statistics for fetal death include only deaths occurring in utero in which the fetus weighs 500 grams or more. The ACOG also recommends including deaths occurring at 22 weeks?gestation or after (other groups use gestation of 20 wk). Although this definition of fetal death is the one used most frequently in the medical literature, it is by no means the only definition in use, even in the US.

In 1997, the fetal death rate in the US was 5.8 deaths per 1000 births. This rate has been decreasing steadily in the US during the past 50 years. Worldwide, the fetal death rate varies considerably depending on the quality of available medical care.

In the US, the rate of fetal death is higher in Hispanic and African American populations than in other populations.

History and physical examination are of limited value in the diagnosis of fetal death. In most patients, the only history obtained is that of a recent absence of fetal movement. Inability to obtain fetal heart tones upon examination suggests fetal demise. However, this finding is not diagnostic, and death must be confirmed by ultrasound studies.

Occasionally, fetal demise occurs in a patient being followed for a high-risk condition, and fetal surveillance may reveal signs of fetal deterioration prior to death. Rarely, fetal demise occurs during labor.

Causes include conditions outlined in the categories below. Some overlap exists among the categories. Many cases of abruptio placenta result from hypertension in the mother. Advanced maternal age contributes to an increased incidence of genetic abnormalities in the newborn.

• Maternal
  • Prolonged pregnancy
  • Diabetes
  • Infection
  • Hypertension
  • Preeclampsia
  • Hemoglobinopathy
  • Advanced maternal age
  • Rh disease
  • Uterine rupture
  • Antiphospholipid syndrome
  • Hereditary thrombophilias
• Fetal
  • Multiple gestations
  • Congenital abnormality
  • Genetic abnormality
  • Infection
• Placental
  • Cord accident
  • Abruption
  • Premature rupture of membranes
• Unknown

Diabetes testing: Undiagnosed diabetes is less common today because of the use of diabetic screening in the second trimester. In the event of fetal death, the mother should be retested for diabetes. Obtaining a random or postpartum glucose level probably is adequate for hospitalized patients. Some authorities recommend a glucose tolerance test 6 weeks postpartum.

Antibody screen: Antibody screening should be repeated to rule out the presence of antibodies to fetal blood.

CBC with platelet count: A CBC may be helpful for detecting undiagnosed hemoglobinopathy. Hemoglobin electrophoresis should be performed if the mean corpuscular volume is less than 80.

Kleihauer-Betke test: This test is used to diagnose fetal-maternal hemorrhage. In the case of major fetal-maternal hemorrhage in a mother who is Rh negative, the regular 300-microgram dose of anti-D immunoglobulin may be insufficient and a higher dose may be required. Typically, 300 micrograms of anti-D immunoglobulin binds 15 mL of fetal red cells.

Lupus anticoagulant and anticardiolipin antibodies: Screening for antiphospholipid syndrome is appropriate following fetal death (especially midtrimester) if another cause is not apparent. Quantitative titers (IgG) for anticardiolipin antibodies are necessary and must be present in the medium-to-high positive range to be significant. Lupus anticoagulant is reported as positive or negative.

Thyroid-stimulating hormone levels and Venereal Disease Research Laboratory test: The patient should be tested for syphilis and thyroid disease.

Cytomegalovirus or toxoplasmosis titers (immunoglobulin M [IgM] and immunoglobulin G [IgG] titers): Tests for cytomegalovirus, toxoplasmosis, or rubella may be indicated depending on clinical findings. Obtaining acute and convalescent IgG and IgM titers is necessary.

Hereditary thrombophilia test: Testing for hereditary thrombophilias is indicated if the patient’s personal or family history suggests the presence of one of these conditions. The hereditary thrombophilias (eg, antithrombin III deficiency, protein C deficiency, protein S deficiency, activated protein C resistance, hyperhomocystinemia) now are thought to be associated with an increased incidence of fetal death. Evaluation is indicated if other causes are not present or if the patient has a personal or family history of thromboembolic events. Authorities have differing opinions about whether this expensive testing should be ordered for patients without a suggestive history. Testing is most accurate if performed after the postpartum period.

A particular medical problem identified in the mother should be addressed prior to future conception. For example, appropriate control of blood glucose prior to conception can substantially reduce the risk of congenital anomalies in the fetus. If congenital anomalies or genetic abnormalities are found, preconceptual counseling is helpful. Genetic screening and detailed ultrasound can be used to evaluate future pregnancies.

In some cases, such as cord occlusion, the patient can be assured that recurrence is very unlikely.