Committee opinion no. 529: placenta accreta

Placenta accreta is a potentially life-threatening obstetric condition that requires a multidisciplinary approach to management. The incidence of placenta accreta has increased and seems to parallel the increasing cesarean delivery rate. Women at greatest risk of placenta accreta are those who have myometrial damage caused by a previous cesarean delivery with either an anterior or posterior placenta previa overlying the uterine scar. Diagnosis of placenta accreta before delivery allows multidisciplinary planning in an attempt to minimizepotential maternal or neonatal morbidity and mortality. Gray scale ultrasonography is sensitive enough and specific enough for the diagnosis of placenta accreta; magnetic resonance imaging may be helpful in ambiguous cases. Although recognized obstetric risk factors allow the identification of most cases during the antepartum period, the diagnosis is occasionally discovered at the time of delivery. In general, the recommended management of suspected placenta accreta is planned preterm cesarean hysterectomy with the placenta left in situ because attempts at removal of the placenta are associated with significant hemorrhagic morbidity. However, surgical management of placenta accreta may be individualized. Although a planned delivery is the goal, a contingency plan for an emergency delivery should be developed for each patient, which may include following an institutional protocol for maternal hemorrhage management.