Risk of late first and second trimester miscarriage after induced abortion.

A cohort of 3110 women anticipating delivery were interviewed after their first prenatal visit at private obstetric practices and HMOs in Connecticut. In all 19.57% reported a prior induced abortion. The research participants were followed to determine whether the pregnancy was miscarried or delivered. In all, 2.19% miscarried in the late first or second trimester. The association of a prior induced abortion on risk for late miscarriage was analyzed by pregnancy history. Women who aborted their first pregnancy had no increased risk (RR = 0.56, 95% CI = 0.16, 1.92) of miscarriage compared with women pregnant for the first time, or compared with women experiencing their second pregnancy after delivering the first (RR = 0.69, 95% CI = 0.18, 2.60). No evidence was found for an increased risk of multiple induced abortion on subsequent miscarriage.