The placenta accreta spectrum is a group of placental abnormalities based on adherence of the placenta, including placenta accreta, increta, and percreta.2 Placenta accreta is defined as abnormal trophoblast invasion of part or all of the placenta into the myometrium of the uterine wall.3 Placenta accreta is when the placental villi attach to the myometrium. In placenta increta, the villi penetrate into the myometrium and in placenta percreta, the villi penetrate through the myometrium to the uterine serosa or other organs.4 The chief risk factors for placenta accreta spectrum are previous c-sections, previous placenta previa, or previous uterine surgery.3
Placenta accreta spectrum is often diagnosed with ultrasound. An MRI may be used to evaluate the placenta further, but MRI has not been proven to improve the accuracy of diagnosis.
Women with placenta accreta spectrum should deliver in an experienced, high-level of maternity care center with a multi-disciplinary team.5 This team should minimally include experienced obstetricians, maternal-fetal medicine specialists, pelvic surgeons, urologists, interventional radiologists, anesthesiologists, critical care experts, general surgeons, and neonatologists.3 These women should usually deliver between 34 0/7 – 35 6/7 weeks gestation. Earlier delivery may be recommended. Before the woman delivers, she should have pre-op consultations with appropriate providers and have her hemoglobin maximized. All team members should be aware of the time of scheduled c-section. During surgery, cell saver should be used, and blood products should be available. Postoperative care may require intensive care.3
Women with placenta accreta spectrum are at high risk for hemorrhage. A hysterectomy may be necessary to stop hemorrhage during delivery. These women may also have an injury to other organs and require extensive surgery. The fetus is at risk for preterm delivery.