The effects of previous induced abortion on pregnancy, labor and outcome of pregnancy were measured in a prospective study of 11,057 pregnancies to West Jerusalem mothers who were interviewed during pregnancy and who subsequently delivered a single live or stillborn infant. The 752 mothers who reported one or more induced abortions in the past were more likely, at the same interview, to report bleeding in each of the first 3 months of the present pregnancy. They were subsequently less likely to have a normal delivery and more of them needed a manual removal of the placenta or other intervention in the third stage of labor. In births following induced abortions, the relative risk of early neonatal death was doubled, while late neonatal deaths showed a 3- to 4-fold increase. There was a significant increase in the frequency of low birthweight, compared to births in which there was no history of previous abortion. There were increases in major and minor congenital malformations, but no significant changes in stillbirth or post-neonatal death rates, nor in mean birthweight or sex ratio. When the effects of other variables were taken into account, there were no significant changes in frequency following an induced abortion as to: ABO and rhesus isoimmunization, toxemia, hydramnios, premature rupture of membranes, induction of labor, breech or vacuum delivery, cesarean section, breech presentation, placenta previa, placental abruption, cord prolapse, cord anomalies, fetal distress or asphyxia, post-partum hemorrhage.