Previous history of surgically induced abortion and complications of the third stage of labour in subsequent normal vaginal deliveries

Objective. To estimate the risk of complications of the third stage of labour needing manual revision of uterine cavity or curettage in deliveries following one or multiple induced abortions in nulliparous women who had singleton live births in Estonia in 1994-2002. Methods. Registry study using the data from the Estonian medical birth registry: 32,652 women had not had any abortions, 7333 women had had one and 2383 women had had two or more surgically induced abortions before their first delivery. Multiple logistic regression analysis was performed to estimate crude odds ratios (OR), adjusted ORs and their 95% confidence intervals, with women having had no abortions as the reference group. Adjustment was made for maternal age, sex and weight of infant, labour induction/augmentation. Results. In the single abortion group, the crude OR was 1.25 (95% confidence intervals (CI) 1.12-1.40), the adjusted OR was 1.23 (95% CI 1.10-1.38); in the multiple abortion group the crude OR was 1.28 (95% CI 1.06-1.53), the adjusted OR was 1.24 (95% CI 1.03-1.49). Conclusions. Our findings suggest a positive association between one or more first trimester abortion(s) and the risk of complications in the third stage of labour in subsequent singleton delivery.