(789) Does premature rupture of membranes affect adverse health outcomes in second trimester medical abortion

Previable and peri-viable preterm rupture of membranes are frequently managed with medication abortion (MAB). Little is known about how ruptured membranes affect labor duration or maternal or health outcomes in MAB when compared to intact membranes.

Study Design:

This retrospective cohort study examined patients undergoing second-trimester (2T) MAB of a singleton pregnancy at 4 academic health centers from 2009-2019. Patients who received a diagnosis of preterm labor or advanced cervical exam prior to MAB were excluded. The primary exposure was rupture of membranes (ROM) or intact membranes (IM) prior to MAB. Patients with infection diagnosed at the start of induction were included. The primary outcome was duration of labor in hours. Secondary outcomes were composite morbidity (uterine rupture, blood transfusion, intensive care unit admission, or readmission) and its components, estimated blood loss (EBL) ³500 mL and clinical chorioamnionitis (CC) Bivariate analyses were performed for composite morbidity and its components due to low frequency of outcome occurrence. Multivariate analyses were performed for EBL >500ml and CC. For the primary outcome, a survival analysis, censoring at the time of delivery, was performed.

Results:

1,341 patients were included, 344 (25.7%) with ROM and 997 (74.3%) with IM. On bivariate analyses, there were significant differences in baseline characteristics between groups (Table1). ROM was associated with decreased labor duration compared to IM (HR 2.5, 95% CI 2.1-2.9); this was significant after adjusting for age, race, body mass index, parity and site of delivery (aHR 2.4, 95% CI 2.1-2.8), (Figure1). There were no significant differences in secondary outcomes, with the exception of a higher likelihood of EBL ³500 (aRR 1.54, 95% CI 1.1-2.2) and CC (aRR 1.9, 95% CI 1.3-2.7).

Conclusion:

ROM prior to 2T MAB is associated with shorter labor duration labor than IM. There was an increased likelihood of CC and higher blood loss without need for blood transfusion among people with ROM. These findings can be used in counseling patients undergoing 2T MAB.