Congenital defect rates among spontaneous abortuses: twenty years of monitoring.

A 20-year study of 1,124 spontaneously aborted embryos and fetuses found 214 (19.0%) to have a localized defect or identifiable syndrome. No clear trend of change over time was noted. The rate is compared with other studies of spontaneously aborted specimens and is approximately ten times higher than in newborns. Forty (3.6%) had neural tube defects and 30 (2.7%) had a clinically recognized chromosomal phenotype. Fifteen had Turner's phenotype, four trisomy 18, and 11 triploidy. Amniotic bands occurred in eight. Two had bilateral renal agenesis. Thirty had some form of facial cleft.