Anencephaly: changes in prenatal detection and birth status, 1972 through 1990.

OBJECTIVE: We assessed at a large university hospital the effect of prenatal diagnosis on the birth of infants with anencephaly between 1972 and 1990. STUDY
DESIGN: All 175 affected infants were identified by a postnatal Malformations Surveillance Program, which included stillborn infants and elective terminations in the second trimester. The affected infants were subdivided into those whose mothers had always planned delivery at this hospital (nontransfers) and those whose mothers had planned delivery elsewhere but were transferred after the prenatal detection of the fetal abnormality (transfers).
RESULTS: In the 1970s half the infants were anencephaly were born alive; the average gestational age was 35.6 weeks, and only a few were diagnosed prenatally. By 1988 to 1990 all affected infants were diagnosed either by prenatal ultrasonography or as the result of maternal serum alpha-fetoprotein screening; the parents elected to terminate the pregnancies, and the average gestational age was 19.6 weeks.
CONCLUSION: Prenatal detection and the selection by parents of the option of elective termination of pregnancy has altered significantly the birth status of infants with anencephaly since 1972.