460: Prior spontaneous preterm birth is not associated with maternal morbidity in subsequent pregnancies

Abstract

Emerging data suggests that placental malperfusion and subsequent placental dysfunction may play a significant role in the pathophysiology of spontaneous preterm birth (PTB). The placental response to malperfusion is thought to lead to a pro-inflammatory state. We hypothesized that PTB patients with a history of prior spontaneous preterm birth (pSPB) may prone to recurrent placental dysfunction and in subsequent pregnancies and not only at increased risk of recurrent PTB but to maternal morbidity as well. This study aimed to determine if history of pSPB is associated with maternal morbidity in subsequent pregnancies. This was a retrospective cohort study of all women with two pregnancies at an academic tertiary care institution from 2004 to 2014. Pregnancy outcomes, and maternal morbidity rates were compared between women with a history of pSPB and with a history of prior spontaneous term birth. The primary outcome was composite morbidity, comprised of postpartum hemorrhage (PPH), transfusion, wound infection, fever, & endomyometritis. T-tests & Mann- Whitney U tests were used for continuous variables and chi-square/Fisher’s exact tests for categorical variables. 3,202 patients had at least two pregnancies in the study period, and 695 (21.7%) patients had a history of a prior spontaneous preterm birth. Patients with pSPB were more likely to be African-American, and develop a hypertensive disorder. The current pregnancies of patients with pSPB were more likely to result in vaginal delivery at earlier gestation, and have lower birth weights. The composite maternal morbidity rate, PPH, transfusion and infection rates were similar. In this study, patients with a pSPB do not appear to be at an increased risk of maternal morbidity in subsequent pregnancies. Further pursuit with a larger population evaluating not only maternal morbidity but neonatal outcomes as well may be helpful to determine the overall risk of morbidity in subsequent pregnancies of women with history of prior SPB.