Induced abortion and congenital malformations in offspring of subsequent pregnancies.

A case-control (n = 1427 and 3001, respectively) study in Connecticut found no relationship between delivery of an infant with congenital malformations and overall previous experience of induced abortion (odds ratio (o) = 0.9, 95% CL = 0.7, 1.1). Delivery of a congenitally malformed infant was also unrelated to: 1)abortion of penultimate pregnancy, 2) abortion of first pregnancy when index pregnancy is second, and 3) multiple previous abortions. Non-white women aged 25-29 who delivered a malformed child were significantly more likely to have aborted ( o = 2.6,95% CL = 1.2, 5.8, p less than 0.05). This may be due to more frequent histories of illegal and septic abortion, or to other characteristics of these women. Legal abortion performed under safe clinical conditions appears to impose no increased risk for subsequent delivery of a malformed infant.