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367: Routine ultrasound screening for placenta accreta, “The Accreta Scan”, in women undergoing repeat cesarean section does not predict intraoperative hemorrhage and may increase rates of cesarean hysterectomy

      Objective

      We determine whether routine ultrasound exam for placenta accreta in women with prior cesarean delivery, termed “Accreta Scan”, corresponds with intraoperative hemorrhage and morbidity.

      Study Design

      A case control study was performed using 640 women who were delivered by repeat cesarean section between 2007-2008. Women who served as cases were prospectively screened for sonographic evidence of placenta accreta at a mean gestational age of 33 weeks (N=149). The remaining 491 women were not screened and served as controls. Opertative findings, hemorrhage, blood transfusion, and pathologic specimens were compared for cases and controls. The sensitivity and positive predictive value of the Accreta Scan for placenta accreta and hemorrhage were determined.

      Results

      The incidence of Accreta was 12/1000 in the total group. Accreta with anterior placenta without previa occurred in 4/1000 women. Pathologic incidence of Accreta for cases and controls was the same (0.13 vs. 0.10, p= 0.8). Demographics were the same for cases and controls. Uterine atony, cesarean hysterectomy, and volume of blood products transfused were greater in the screened women. The sensitivity of the accreta scan was 50%, PPV of 25% for accreta and 14% for hemorrhage.

      Conclusion

      There is no correlation between an accreta scan and hemorrhage at repeat cesarean section. This is likely due to the low incidence of accreta in the absence of placenta previa, and other more common causes of intraopertive hemorrhage. Routine screening for placenta accreta may set the stage for more cesarean hysterectomies.
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