Placenta accreta spectrum is considered a high-risk condition with serious associated morbidities therefore, ACOG and the Society for Maternal–Fetal Medicine recommend these patients receive level III (subspecialty) or higher care. This designation is referred to as “levels of maternal care,” and exists for conditions such as placenta accreta spectrum. In 2015, the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal–Fetal Medicine developed a standardized risk-appropriate maternal idealized care system for facilities, based on region and expertise of the medical staff, to reduce overall maternal morbidity and mortality in the United States 3. Additionally, patients with placenta accreta spectrum are more likely to require hysterectomy at the time of delivery or during the postpartum period and have longer hospital stays 2. Rates of maternal death are increased for women with placenta accreta spectrum 1 2. Maternal morbidity and mortality can occur because of severe and sometimes life-threatening hemorrhage, which often requires blood transfusion. Placenta accreta spectrum, formerly known as morbidly adherent placenta, refers to the range of pathologic adherence of the placenta, including placenta increta, placenta percreta, and placenta accreta. Is defined as abnormal trophoblast invasion of part or all of the placenta into the myometrium of the uterine wall 1. In addition, established infrastructure and strong nursing leadership accustomed to managing high-level postpartum hemorrhage should be in place, and access to a blood bank capable of employing massive transfusion protocols should help guide decisions about delivery location. Optimal management involves a standardized approach with a comprehensive multidisciplinary care team accustomed to management of placenta accreta spectrum. The most generally accepted approach to placenta accreta spectrum is cesarean hysterectomy with the placenta left in situ after delivery of the fetus (attempts at placental removal are associated with significant risk of hemorrhage). Antenatal diagnosis of placenta accreta spectrum is highly desirable because outcomes are optimized when delivery occurs at a level III or IV maternal care facility before the onset of labor or bleeding and with avoidance of placental disruption. The most common is a previous cesarean delivery, with the incidence of placenta accreta spectrum increasing with the number of prior cesarean deliveries.
There are several risk factors for placenta accreta spectrum. Although ultrasound evaluation is important, the absence of ultrasound findings does not preclude a diagnosis of placenta accreta spectrum thus, clinical risk factors remain equally important as predictors of placenta accreta spectrum by ultrasound findings. The most favored hypothesis regarding the etiology of placenta accreta spectrum is that a defect of the endometrial–myometrial interface leads to a failure of normal decidualization in the area of a uterine scar, which allows abnormally deep placental anchoring villi and trophoblast infiltration. ABSTRACT: Placenta accreta spectrum, formerly known as morbidly adherent placenta, refers to the range of pathologic adherence of the placenta, including placenta increta, placenta percreta, and placenta accreta.