Factors involved in resolution of placenta previa diagnosed on second trimester ultrasound

Abstract

ON SECOND TRIMESTER ULTRASOUND BRIAN WAGNER, RODNEY WRIGHT, JOHN ILAGAN, PETER S. BERNSTEIN, Albert Einstein College of Medicine/ Montefiore Medical Center, Obstetrics & Gynecology and Women’s Health, Bronx, New York OBJECTIVE: Placenta previa is commonly diagnosed on second trimester ultrasounds causing patient and provider anxiety. Our objective was to determine factors associated with the persistence of placenta previa diagnosed on prenatal ultrasound in order to guide patient counseling. STUDY DESIGN: A retrospective cohort review was performed on all patients diagnosed with placenta previa and marginal placenta previa on ultrasound from 2003 to 2005. Using the AS-OBGYN computerized patient record, those patients with the terms ‘‘placenta previa’’ or ‘‘marginal placenta previa,’’ within the ultrasound reports were identified. A medical records review was then undertaken to identify those factors that are related to the resolution or continuance of the previa. Information including type of previa, gestational age at diagnosis, maternal age, parity, previous uterine surgery including cesarean delivery, curettage and myomectomy, race and smoking history were recorded. RESULTS: 532 patients were identified and after exclusion for incomplete data collection, 511 records were available for this analysis. In univariate analysis, later mean gestational age at diagnosis (22.5G5.52 v. 19.1G3.79 weeks, p!0.04), smoking (OR 8.14; 95% CI 4.18,15.92), complete previa (OR 16.98; 95% CI 9.36, 30.95), multiparty (OR 3.81; 95% CI 2.02-7.28), previous uterine curettage (OR 1.62; 95% CI 1.01, 2.62) and previous cesarean delivery (OR 16.98; 95% CI 7.93, 24.15) were all independent risk factors for persistence of placenta previa to delivery. In a multivariate analysis, only later gestational age at diagnosis, complete previa and previous cesarean delivery remained risk factors for persistence until delivery. CONCLUSION: Type of placentation, history of prior cesarean delivery, and gestational age at diagnosis are all important factors that modify the risk that a previa will persist to delivery. Using these risk factors providers may be able to individualize patient counseling on the risk of persistence of placenta previa diagnosed during second trimester ultrasounds.