Interpregnancy interval and abnormally invasive placentation.

Abstract

The presence of a previous uterine scar is a strong risk factor for developing abnormally invasive placentation (AIP). We sought to determine whether a short interpregnancy interval predisposes to AIP. We hypothesized that a short interpregnancy interval after a previous cesarean delivery increases the risk of AIP in comparison with a longer interpregnancy interval. We performed a retrospective cohort study of women with a histological diagnosis of AIP and a history of a previous cesarean section. Women were included in the control group if they had a previous cesarean section with a placenta underlying the previous uterine scar or an anterior previa. The time interval between pregnancy and AIP data was analyzed using the chi-square test and two-tailed Fisher's exact test. There was no statistical difference in the interpregnancy interval between women who had AIP vs the control group. Gravidity and parity were found to be significantly higher in the women with AIP vs the controls. These results suggest that a short interpregnancy interval may not increase the risk of developing AIP.