(875) Preterm Birth is a Risk Factor for Intrapartum Complications in a Subsequent Term Delivery

We performed a retrospective cohort study reviewing medical records of all women who delivered their first and second deliveries at a tertiary hospital between 2012 and 2020. We compared three groups of parturient that delivered at term in their second delivery, according to gestational age in their first delivery: (1) before 34 weeks; (2) between 34+0 and 36+6 weeks and (3) first delivery at term (≥37 weeks).


Results:

During the study period, 7264 women met the inclusion criteria; Forty-one women (0.56%, group 1) delivered before 34 weeks of gestation in their first delivery, 262 women (3.6%, group 2) between 34 to 36+6 weeks, and 6961 (95.8%, group 3) delivered their first delivery at term. A first preterm delivery (PTD) was significantly associated with a higher rate of cesarean delivery (CD) in the second term delivery for each group of patients (17% vs. 7.25% vs. 5.40% in groups 1,2 and 3, respectively, p< 0.005). Moreover, among those who delivered by CD in their second delivery, more urgent cesarean deliveries were noted (85% in group 1, 78.9% in group 2 and 48.4% in group 3. p=0.0058). A first PTD was also significantly associated with instrumental vaginal delivery in the second delivery (12.2% vs. 5.75% and 3.02% in groups 1,2 and 3 respectively. p< 0.005). On multivariate regression analysis controlling for maternal age, gestational age at second delivery, instrumental delivery at first delivery and gestational diabetes mellitus, first preterm delivery before 34 weeks was found to be an independent risk factor for cesarean delivery and instrumental vaginal delivery in the second term delivery (aOR=3.13, CI 95% 1.34-7.32; and aOR=11.44, CI 95% 4.21-30.9, respectively).


Conclusion:

PTD in the first delivery is an independent risk factor for intrapartum complications in a subsequent term delivery, including higher risk of CD, urgent CD and instrumental vaginal delivery.