368: Hemorrhagic morbidity of invasive placentation with and without placenta previa

Abstract

To compare hemorrhagic morbidity among pregnancies affected by invasive placentation with and without co- existing placenta previa We conducted a retrospective cohort study of deliveries at a tertiary care center from 1997 to 2017 with histologically-confirmed invasive placentation. The primary outcome was transfusion of any blood product; secondary outcomes were transfusion of specific blood products, estimated blood loss, number of units transfused and intensive care unit admission. Risk ratios (RR) and 95% confidence intervals (CI) are reported. We identified 105 pregnancies complicated by invasive placentation, 47 with previa and 58 without. Women with previa were more likely to have an antenatal diagnosis of invasive placentation, a greater depth of invasion and to deliver at an earlier gestational age (all p<0.001). After adjusting for depth of invasion, women with pregnancies complicated by previa were more likely to receive a blood transfusion compared to those without (RR: 2.0; 95% CI: 1.3-3.1). Women with previa were more likely to receive packed red blood cells, platelets and cryoprecipitate, but not fresh frozen plasma or cell saver (Table 1). Compared to deliveries among women without previa, those with previa were complicated by larger median estimated blood loss and more units of packed red blood cells transfused (both p≤0.03), though the number of units of fresh frozen plasma and cryoprecipitate were similar (both p≥0.53). Women with previa were more likely to have a hysterectomy (crude RR 2.7; 95% CI: 1.8-3.8) and be admitted to the intensive care unit (RR: 3.3; 95% CI: 1.1-9.6, adjusted for depth of invasion). Among pregnancies complicated by invasive placentation, those with co-existing placenta previa experienced greater hemorrhagic morbidity as compared to those without. Given the increased morbidity, pregnancies complicated by both invasive placentation and placenta previa warrant multi-disciplinary pre- operative planning and care.