Dynamic Change of Placenta Previa From Second Trimester to Delivery: a Retrospective Longitudinal Study Cohort

Abstract Introduction: Placenta previa contributes greatly to severe antenatal and post-partum hemorrhage in obstetrics. Previous studies have mainly focused on the risk factors of placenta previa, and very limited studies have reported which factors may affect the dynamic outcome of placenta previa in the second trimester. The aim of this study was to investigate the impact of maternal and neonatal characteristics on dynamic change of placenta previa from second trimester to delivery.Methods: A retrospective longitudinal sub-cohort investigation was carried out among 510 pregnant women with placenta previa in second trimester of pregnancy from the Longitudinal Placenta Previa Study (LoPPS). Logistic regression analysis was used to discover the connections between maternal covariates and dynamic change process of placenta. Multivariable linear regression analysis was used to detect the associations between perioperative characteristics and the volume of intraoperative bleeding. Results: Among the pregnant women with major placenta previa in the second trimester, 28.8% of them were without placenta previa at delivery, and 25.5% morphed into minor placenta previa. There was significant correlation between placenta previa type and pre-pregnancy BMI (Beta: 0.141, 95% CI: 0.046,0.235. p=0.003), gestational age (Beta: -0.355, 95% CI: -0.507, -0.204. p<0.001) and times of prior cesarean section (Beta: 0.161, 95% CI: 0.050,0.271. p<0.001). Conclusion: 71.2% of the pregnant women with major placenta previa in the second trimester were still with placenta previa at delivery, and the proportion may be higher in pregnant women suffering previous cesarean section and with high pre-pregnancy BMI.