CREOG Quiz #372

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.

  1. Which of the following was this patient’s most important risk factor for placenta percreta?

    •  Advanced maternal age
    •  Two previous cesarean deliveries
    •  Placenta previa
    •  Prior spontaneous abortions

  2. Considering this patient’s diagnosis, what is the most appropriate delivery plan?

    •  Induction of labor at 40 weeks with placenta left in situ
    •  Cesarean delivery at 40 weeks with placenta left in situ
    •  Cesarean hysterectomy at 34-36 weeks

  3. What is the average blood loss at delivery in women with a placenta accreta?

    •  500 mL
    •  1000 mL
    •  4000 mL
    •  8000 mL


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

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