PRENATAL-DIAGNOSIS BY CHORIONIC VILLUS SAMPLING IN MULTIPLE PREGNANCIES PRIOR TO FETAL REDUCTION

Ovulation induction and assisted-reproduction techniques have dramatic ally increased the incidence of high-risk multiple pregnancies over th e past 10 years. Perinatal outcome may be improved by the use of multi fetal reduction. The fetus to be reduced used to be selected only on t echnical grounds, We report on the results of prenatal diagnosis by ch orionic villus sampling (CVS) during the first trimester in 32 multife tal pregnancies in which fetal reduction was requested. The mean gesta tional age at CVS was 10.5 weeks. Chromosomal analyses were available for all sampled fetuses, three of which were chromosomally abnormal. I n 24 couples, fetal reduction to twin pregnancies was successfully car ried out within 1 week after the CVS, In seven cases, the couples elec ted not to proceed with fetal reduction after receiving information th at the chromosomal analysis was normal in all fetuses. Mean gestationa l ages at delivery were, respectively, 34.6 and 31.8 weeks in the redu ced and the nonreduced groups (p = 0.04). No fetal losses occurred in either group; one neonatal death was observed after a preterm delivery because of preeclampsia in a twin pregnancy. Prenatal cytogenetic dia gnosis during the first trimester in multiple pregnancies prior to fet al reduction appears to be feasible, accurate, and safe, Abnormal chro mosomal results indicate the fetus(es) to be reduced. The parents' dec isions not to proceed with the fetal reduction procedure, where chromo somal results in all the fetuses were normal, were unexpected.