Association between interpregnancy interval and adverse perinatal outcomes among subsequent twin pregnancies: a nationwide population-based study

The existing evidence on the association between interpregnancy interval (IPI) and pregnancy outcomes primarily focuses on singleton pregnancies, with limited research on twin pregnancies. This study aimed to investigate the association between IPI and adverse perinatal outcomes in twin pregnancies. This population-based, retrospective cohort study analyzed data from the National Center for Health Statistics in the United States between 2016 and 2020. We included multiparous women aged 18 to 45 years with live-born twins without congenital anomalies, born between 26 and 42 weeks of gestation. Poisson regression models, adjusted for potential confounders, were used to evaluate the associations between IPI and adverse outcomes, including preterm birth (PTB)