Genetic evaluation. If autopsy and chromosomal studies are performed when indicated, up to 35 percent of stillborn infants are discovered to have congenital structural anomalies (Faye-Paterson and associates, 1999; Mueller and colleagues, 1983). As many as 8 percent of stillbirths have chromosomal abnormalities, and about 20 percent have dysmorphic features or skeleton abnormalities (Pauli and Reiser, 1994; Saller and colleagues, 1995). It is probably not cost effective to perform cytogenetic analyses in al stillbirths. Instead, the American College of Obstetricians and Gynecologists (1996) recommends consideration of cytogenetic studies for infant with dysmorphic features, inconsistent growth measurements, anomalies, hydrops, or growth restriction. Such studies might also be considered in cases in which absolutely no other explanation for the loss is found. Another indication is a parent who is a carrier for a balanced translocation, a mosaic chromosomal pattern, or a history of recurrent losses or stillbirths in first-degree relatives.
Appropriate consent must be obtained to take skin and other tissue samples, including fluid obtained by needle postmortem. A total of 3 mL of fetal blood, obtained from the umbilical cord (preferably) or by cardiac puncture, is placed into a sterile, heparinized with attached dermal tissue should measure 1 cm2 and be washed with sterile saline prior to placement in saline or alcohol prohibits cytogenetic analysis because the cells must remain alive for study. If the skin is macerated, 1 cm2 sample of fascia should be obtained from the thigh, inguinal region, or Achilles tendon. Because a traditional cytogenetic study requires that fetal cells be stimulates to divide, it may not be possible in cases with prolonged intrauterine retention. However, fluorescent in situ hybridization (FISH) might be used to rule out trisomies or to look for certain common deletions such as DiGeorge syndrome.