The impact of obstetrical anal sphincter injuries on the interpregnancy interval and pregnancy complications of subsequent delivery: A retrospective study.

Objective: Our primary objective was to evaluate the interpregnancy interval (IPI) of women who have experienced obstetric anal sphincter injuries during delivery. Additionally, we compared adverse perinatal outcomes in subsequent deliveries following obstetric anal sphincter injuries (OASIS) in women with longer and shorter IPIs.

Methods: This retrospective cohort study included women who had a subsequent pregnancy following OASIS and women without a history of such injuries, who delivered in a tertiary medical center between 2015 and 2019. Data were retrieved from patient computerized medical records. Kaplan-Meier curves and Cox regression analysis were used to evaluate the IPI defined as the time from delivery to the last menstruation prior to the subsequent delivery. Data analysis for our secondary objective was performed using mean and standard deviation for quantitative variables.

Results: During the study period, 233 women experienced OASIS (0.27%), of whom 142 met the study criteria. There was no significant difference in the mean IPI between women in the two groups. However, women were significantly more likely to have a repeat perineal tear (49 [34.5%], P < 0.001), an episiotomy (16 [11.3%], P < 0.001), and an elective or an emergency cesarean section (60 [42.3%], P < 0.001) in their subsequent delivery. There was no difference in pregnancy outcomes among women who had a long compared with a short IPI.

Conclusions: Women do not delay or avoid childbirth after experiencing OASIS. However, women are more likely to experience perineal tears, episiotomies, or a cesarean delivery in the subsequent pregnancy.