What is the risk of placenta accreta in a patient with a history of one prior cesarean and previa?

In patients who have a history of one prior cesarean section and are diagnosed with placenta previa, the risk of placenta accreta is significantly increased. Studies have shown that the presence of anterior placenta previa combined with a history of cesarean delivery raises the likelihood of abnormal placentation, including placenta accreta. Specifically, with one previous cesarean and placenta previa, the risk has been identified to be around 11%.

Patients with a singular cesarean section already face a baseline elevation in risk for various complications, and the presence of placenta previa further compounds this risk. This interaction is due to scar tissue from the previous surgery which can disrupt the normal implantation site of the placenta, leading to abnormal adherence to the uterine wall.

Understanding this risk is crucial in managing such pregnancies, as it necessitates careful monitoring and planning for delivery, potentially with a scheduled cesarean to reduce the chance of severe complications during labor.