556 Resolved but not forgotten: does a diagnosis of resolved placenta previa affect labor and delivery?

Abstract

Placenta previa (PP) is diagnosed in up to 15% of pregnancies at the anatomy ultrasound (US) and 0.5% persist to term. There is limited data regarding pregnancy outcomes with resolved previa (RPP). We aim to examine patients with RPP to determine if abnormal placentation at any time during pregnancy is associated with adverse events during labor. Anatomy US done at the Mount Sinai West Fetal Evaluation Unit between Mar 2018 - June 2020 were reviewed. Patients with PP were identified, included if PP resolved with placental edge >2cm from os, excluded if PP persisted to term, resolution occurred prior to 20 weeks, prior cesarean delivery or missing outcomes. Time matched controls identified among patients with normal placentation. Demographic data and outcomes collected. Student t-test, Wilcoxon rank-sum test, Chi-square, Fisher exact test, Univariable and multivariable logistic regression were used as appropriate A total of 8,881 US were performed, 560 with PP, 275 identified as RPP, 285 excluded. RPP patients were significantly older with lower pre pregnancy BMI. Patients with RPP were significantly more likely to be a current smoker, have used assisted reproductive technology, have had previous uterine surgeries (Table 1). Patients with RPP were 5.2 times more likely to have a post partum hemorrhage (PPH) (OR 5.2, 95% CI 2.1-12.7; p<0.01) and 3.4 times more likely to require extra uterotonic medications (OR 3.4, 95% CI 1.9-6.2; p<0.01). As the placental edge gets farther away from the os at resolution, the risk of PPH decreases (OR 0.9, 95% CI 0.9-1.0; p=0.03). There is no difference with regards to rates of operative delivery or cesarean delivery for fetal distress (OR 1.2, 95% CI 0.7-1.9; p=0.48), or Cat II/III fetal heart tracing at delivery. Patients with RPP had a higher rate of PPH and use of uterotonic agents. They were also more likely to have similar underlying risk factors of patients with persistent PP. This information might have important clinical implications and could be incorporated into the hemorrhage risk assessment during labor.View Large Image Figure ViewerDownload Hi-res image Download (PPT)