Placenta Accreta

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INTRODUCTION: Placenta accreta is an unyielding pregnancy complication with increased morbidity and mortality. Optimal management requires prenatal diagnosis. Currently, ultrasonography and magnetic resonance imaging (MRI) are used for screening. We pursued if a risk assessment tool incorporating both clinical risk factors and screening radiography would give a more accurate prediction. We secondarily calculated ultrasound and MRI sensitivity, specificity, and positive and negative predictive values. METHODS: We performed an institutional review board-approved retrospective cohort analysis from January 2008 to April 2013. Using electronic and ultrasound information systems, women diagnosed with placenta accrete or cesarean hysterectomy were identified. Maternal demographics and operative characteristics and complications obtained. Ultrasonography, MRI, and pathology findings compared. Using our unique screening tool incorporating clinic and radiographic study findings, each woman was given a priori risk number (0–44). Statistical analyses performed using NCSS software. RESULTS: Forty-six underwent cesarean hysterectomy for abnormal placentation. Pathology confirmed 32 of these cases. Ultrasound sensitivity was 89%, specificity was 52%, positive predictive value was 74%, and negative predictive value was 28%. Magnetic resonance imaging sensitivity was 85%, specificity was 100%, positive predictive value was 100%, and negative predictive value was 40%. Using our risk assessment tool, our patients mean scores was 18 with a standard deviation of 4.3. A score of 20+ correlated with proven abnormal placentation by pathology. CONCLUSIONS: Prenatal diagnosis of abnormal placental invasion decreases maternal and fetal morbidities and mortalities. Radiographic screening tools of ultrasonography and MRI are useful but frequently unsatisfying when used in isolation. Combining clinical risk factors with radiographic evidence using our risk assessment instrument may prove useful in designing a more predictable approach for prenatal diagnosis of abnormal placentation.