Preterm delivery is a risk factor for intrapartum complications in a subsequent term delivery

Preterm delivery before 37 weeks is a serious obstetrical complication and the leading cause of neonatal morbidity and mortality. We aimed to evaluate the association between preterm vaginal delivery and intrapartum complications in a subsequent term delivery.

The database of a tertiary hospital was retrospectively reviewed for all women with two consecutive deliveries between 2012 and 2020: a first vaginal delivery and a second term delivery. The cohort was divided by gestational age at first delivery: (1) before 34 weeks; (2) between 34 + 0 and 36 + 6 weeks; and (3) term (≥ 37 weeks).

Among 7264 women, 41 (0.6%) delivered before 34 weeks, 262 (3.6%) between 34 + 0-36 + 6 weeks, and 6961 (95.8%) at term. First preterm delivery was associated with higher rates of cesarean section at second delivery (17.0%, 7.3%, 5.4% in groups 1, 2, 3, respectively, p < 0.005), with higher urgent cesarean rates (85.0%, 78.9%, 48.4%, respectively, p = 0.0058), and higher assisted vaginal delivery rates (12.2%, 5.8%, 3.0%, respectively, p < 0.005). Multivariate analysis controlling for maternal age, gestational age at second delivery, assisted vaginal delivery at first delivery, and gestational diabetes showed first delivery before 34 weeks was an independent risk factor for subsequent cesarean or assisted delivery (aOR = 3.1, 95% CI 1.3-7.3 and aOR = 11.4, 95% CI 4.2-30.9, respectively).

A first preterm delivery poses a risk of intrapartum complications in a subsequent term delivery, including cesarean section, urgent cesarean section, and assisted vaginal delivery.