Relationship Between Extra-Long Interpregnancy Interval and Adverse Perinatal Outcomes in Chinese Women

Objective To evaluate the association between extra-long interpregnancy interval and adverse perinatal outcomes. Methods A retrospective cohort study on women experiencing their second delivery between 2017 and 2018 in a maternal and child health hospital was conducted to evaluate the association between the extra-long interpregnancy interval (IPI) and adverse perinatal outcomes. IPI ≥180 months was defined as extra-long IPI. Logistic regression analysis was performed to explore the adverse perinatal outcomes in different IPI groups, and compared with the predicted risks at 24–59, 60–119, 120–179, and 180-month IPI, with the 12–23-month interval serving as a reference. Results After adjusting for all possible confounding factors, there was an increased risk of premature rupture of membranes (aOR 1.83, 95% CI 1.13–2.97 and aOR 3.30, 95% CI 1.40–7.74) in the IPI of 60–119 and 120–179 months among women with age-appropriate maternity. However, the effects of extra-long IPI on adverse perinatal outcomes did not significantly differ among women with advanced maternal age. Conclusions These results indicate that long IPI (60–179 month) is an independent risk factor for premature rupture of membranes. Extra-long IPI (≥180 months) was not associated with an increase in major morbidity, but extra-long IPI often coexists with advanced age, so we still need to pay attention to the maternal risk factors associated with extra-long IPI.