Long interpregnancy interval and adverse perinatal outcomes: A retrospective cohort study.

We conducted a retrospective cohort study of 9,552 women experiencing their second delivery between 2014 and 2016 at the International Peace Maternity and Child Health Hospital to investigate the association between the interpregnancy interval (IPI) and adverse perinatal outcomes. With the 12-23-mon IPI as the reference category, logistic regression analyzes were used to examine associations between different IPIs (<12, 12-23, 24-59, 60-119, and ≥120 mon) and perinatal outcomes (gestational diabetes mellitus, premature membrane rupture, gestational hypertension, preterm birth, low birth weight, and macrosomia). Compared with the 12-23-mon IPI category, women with longer IPIs had a higher risk of adverse perinatal outcomes, and those with an IPI ≥120 mon had the highest risk of gestational diabetes mellitus and premature membrane rupture (adjusted odds ratio (OR) 1.76, 95% confidence interval (CI) 1.32-2.35 and adjusted OR 2.03, 95% CI 1.53-2.67, respectively). These results indicate that a longer IPI is associated with a higher risk of adverse perinatal outcomes and an IPI of ≥120 mon appears to be independently associated with a higher risk of gestational diabetes mellitus and premature membrane rupture.