308: Relationship between number of prior cesareans and early preterm delivery in women with abnormal placentation

Abstract

To balance perinatal and maternal risks and benefits, delivery timing at 34-36 weeks is recommended for pregnancies complicated by abnormal placentation such as morbidly adherent placenta (MAP). However, it has recently been suggested that those with ≥2 prior cesarean deliveries (CD) and MAP should be delivered earlier than 34 weeks because of a higher risk of complications. We sought to determine the relationship between number of prior CD in women with MAP and early preterm delivery (PTD <34weeks). Additionally, we evaluated the same relationship in a broader group with placenta previa (with or without MAP). This is a secondary analysis of a prospective, multicenter, observational study that included women with prior CD (MFMU Cesarean Registry). Two groups of patients from the registry were studied: patients with MAP and patients with placenta previa regardless of MAP (PP). The exposure of interest was the number of prior CD: ≥2 CD compared to ≤1 CD. The primary outcome was PTD <34 weeks. Secondary outcomes included transfusion of blood products, preterm labor requiring hospitalization/tocolysis, NICU admission, and a composite of maternal and neonatal complications. Balance of maternal demographics in the two groups was assessed using two sample t-tests and chi- square tests, and potential confounders were included in multivariable logistic regression models. Backward selection was used to identify parsimonious models. The MAP analysis included 194 women, 97 (50%) of whom had ≤ 1 prior CD and 97 (50%) of whom had ≥2 prior CD. There was no increased risk of PTD <34 weeks in women with ≥2 prior CD in the setting of MAP (23.7% vs. 29.9%, p=0.27). Only need for plasma transfusion was associated with ≥2 prior CD (29.9% vs. 17.5%, p=0.04) (Table 1). There were 776 women with PP, 667 (86%) with ≤ 1 prior CD and 109 (14%) with ≥2 prior CD. Similarly, there was no increased risk of PTD <34 weeks with ≥2 CD in the setting of PP (27.5% vs. 22.6%, p=0.08). However, it was associated with a higher odds of need for transfusion and the maternal composite outcome (Table 2). Women with MAP or PP who have had ≥2 prior CD did not appear to have a higher risk of complications or PTD<34 weeks. Those with ≥2 prior CD may have a higher risk of maternal complications including need for transfusion products that may be independent of timing of delivery.View Large Image Figure ViewerDownload Hi-res image Download (PPT)