309 Resolved low-lying placenta and placenta previa is associated with increased risk of postpartum hemorrhage

Abstract

Second trimester diagnosis of low placentation, defined as low-lying placenta and placenta previa, is a risk factor for postpartum hemorrhage (PPH), but it is unknown if resolved low placentation leads to higher rates of PPH. Initial implantation of the placenta in the lower uterine segment increases vascularity and may cause unsuccessful contraction of the vascular beds at delivery. We hypothesize despite resolution of low placentation, women are at increased risk of PPH at delivery. This retrospective cohort includes women who delivered at Mount Sinai Hospital from 2015-2019, diagnosed with low placentation at mid-trimester anatomy survey with resolution on subsequent ultrasound. Women with normal placentation at mid-trimester anatomy survey were randomly selected for comparison. Demographic and neonatal characteristics were compared. Primary outcome was PPH. Secondary outcomes included blood transfusion, use of additional uterotonic medication or procedures to control bleeding. Outcomes were assessed using a logistic regression model adjusting for age, BMI and race/ethnicity. Resolved low placentation was associated with older age, lower BMI, White race, IVF and a posterior placenta (p<0.01). Patients with resolved low vs. normal placentation had greater odds of PPH (aOR 3.3, 95% CI 1.9-5.7; p<0.01), additional uterotonic use (aOR 2.1, 95% CI 1.5-3.1; p<0.01) and a trend toward increased rates of additional procedures (aOR 3.6, 95% CI 1.2-11.0; p=0.02) and blood transfusion (aOR 2.0, 95% CI 0.9-4.2; p=0.07). Composite neonatal morbidity was increased in the resolved low placentation cohort (9.1% vs. 4.0%, p<0.01), likely driven by higher rates of hypoglycemia (p<0.01). Women with resolved low placentation are at increased risk of PPH compared to those with normal placentation throughout pregnancy. The trend toward higher rates of additional procedures and blood transfusion suggest women with resolved low placentation may be at increased risk of morbidity. This may alter counseling and delivery management and increase preparation for PPH in these patients.View Large Image Figure ViewerDownload Hi-res image Download (PPT)