A 40-year-old woman, G7P2042, with a history of two prior cesareans, was found to have a placenta previa on an ultrasound at 17 weeks. She was managed expectantly until 32 weeks when she reported hematuria lasting for one week. An MRI was performed (please see illustration below) which showed placenta percreta with bladder wall involvement.
While multiparity and advanced maternal age are definite risk factors for placenta percreta, women at greatest risk of placenta percreta (as well as accreta and increta) are those with a history of previous cesarean delivery who now have a placenta previa in the current pregnancy that overlies the previous uterine scar. One study found that the risk of placenta accreta was 3%, 11%, 40%, 61%, and 67% for the first, second, third, fourth, and fifth or greater repeat cesarean deliveries, respectively, in the presence of placenta previa. Placenta previa without previous uterine surgery is associated with a 1-5% risk of placenta accreta. Given involvement of the bladder wall in this patient, the most appropriate plan for delivery is a planned preterm cesarean hysterectomy at 34-36 weeks. Consultation with a multidisciplinary team composed of a Maternal-Fetal Medicine specialist, urologist, gynecologic oncologist, anesthesiologist, and interventional radiologist is critically important. The average blood loss at delivery in women with placenta accreta is 3,000-5,000mL and as many as 90% of women with a placenta accreta require blood transfusion. Forty percent require more than 10 units of packed red blood cells.
Placenta accreta. Committee Opinion No. 529. American College of Obstetricians and Gynecologists. Obstet Gynecol 2012; 12:207-11