Best Management of Placenta Accreta

Advances in the management of placenta accreta (PA)-when part of the placenta invades and is inseparable from the uterine wall-have been highlighted by The American College of Obstetricians and Gynecologists (ACOG).¹

The incidence of PA has increased in conjunction with the increase in number of cesarean deliveries. The latest reported rate of PA is 1 in 533 pregnancies,² up from 1 in 4027 pregnancies in the 1970s and 1 in 2510 pregnancies in the 1980s.^3,4 Grayscale ultrasonography has a sensitivity of 77% to 87% and a specificity of 96% to 98% for diagnosing PA.¹ Occasionally, MRI is needed when the ultrasound scan is inconclusive. Using gadolinium as a contrast agent for MRI improves the scan’s specificity for PA. However, current recommendations are to avoid gadolinium-enhanced scans during pregnancy.⁵

Typical management of PA is cesarean hysterectomy. Other risks of PA are profuse hemorrhage and possible death. Before surgery, maternal hemoglobin levels should be assessed in preparation for possible massive blood loss.¹ Blood transfusion is required in most cases of PA, and 40% of cases require more than 10 units of packed red blood cells. Use of autologous blood salvage devices may prove helpful during surgery.⁶ Use of balloon catheter occlusion or embolization to reduce blood loss has had mixed results; evidence is insufficient for a firm recommendation for or against the practice.¹

Delivery at a tertiary perinatal care center-where multidisciplinary specialty care and an adequate blood supply typically are available-is ideal. The surgical team should include an experienced obstetric surgeon, aided by a urologist, general surgeon, and gynecologic oncologist. In stable patients, a planned delivery at 34 weeks of gestation with no amniocentesis performed before delivery was shown to optimize outcomes for both the mother and the neonate.⁷ Administration of antenatal corticosteroids should be made on a patient-by-patient basis. Use of methotrexate for postpartum management of PA is unsupported.¹

For women who want to attempt to preserve their fertility, there is an alternate approach involving ligation of the cord close to the fetal surface, removal of the cord, and preservation of the placenta in situ. However, the results are extremely unpredictable and subsequent successful pregnancies are rare.⁸

Pertinent Points:
- The recommended management of placenta accreta is a planned preterm cesarean hysterectomy with the placenta left in situ because attempts at removing the placenta are associated with significant hemorrhagic morbidity, according to ACOG.
- Advanced maternal age, multiparity, and any condition resulting in myometrial tissue damage after a secondary collagen repair are risk factors for placenta accreta.

References:

1. Committee opinion no. 529: placenta accreta. Obstet Gynecol. 2012;120:207-211.
2. Wu S, Kocherginsky M, Hibbard JU. Abnormal placentation: twenty-year analysis. Am J Obstet Gynecol. 2005;192:1458-1461.
3. Read JA, Cotton DB, Miller FC. Placenta accreta: changing clinical aspects and outcome. Obstet Gynecol. 1980;56:31-34.
4. Miller DA, Chollet JA, Goodwin TM. Clinical risk factors for placenta previa-placenta accreta. Am J Obstet Gynecol. 1997;177:210-214.
5. Kanal E, Barkovich AJ, Bell C, et al. ACR guidance document for safe MR practices: 2007. ACR Blue Ribbon Panel on MR Safety. AJR Am J Roentgenol. 2007;188:1447-1474.
6. American College of Obstetricians and Gynecologists. ACOG practice bulletin no. 76: postpartum hemorrhage. Obstet Gynecol. 2006;108:1039-1047.
7. Robinson BK, Grobman WA. Effectiveness of timing strategies for delivery of individuals with placenta previa and accreta. Obstet Gynecol. 2010;116:835-842.
8. Bretelle F, Courbiere B, Mazouni C, et al. Management of placenta accreta: morbidity and outcome. Eur J Obstet Gynecol Reprod Biol. 2007;133:34-39.