Abnormal implantation can prevent normal placental separation in patients with placenta accreta (PA), resulting in massive hemorrhage. Antepartum diagnosis of PA during routine ultrasound permits planned cesarean hysterectomy and can lessen hemorrhagic morbidity associated with this condition. There are no clear guidelines for the timing of planned delivery. To reduce the risk of unscheduled emergent deliveries at term, planned late preterm delivery has been recommended for cases without antepartum bleeding or other complications of pregnancy. Identifying women at highest risk for emergent preterm delivery is desirable because of the ongoing risk of hemorrhage with delayed delivery.
This retrospective cohort study was designed to identify risk factors for emergent preterm delivery in women with placenta previa who have ultrasound findings suspicious for accreta. Demographic data, including risk factors for preterm birth, as well as obstetric and neonatal outcomes, were extracted from electronic medical records. Statistical analysis was performed using Fisher exact test, Mann-Whitney U test, logistic regression, and Kaplan-Meier log rank analysis; continuous data was presented as median (interquartile range).
Twenty-one patients with placenta previa and suspected accreta were delivered at a median gestational age of 34 weeks (32–37). Fourteen of the patients (67%) had at least one bleeding episode before delivery; 10 bled at <32 weeks. Among the 21 patients, 12 had planned deliveries (57%) at a gestational age of 36.5 weeks (34–37) and 9 had emergent deliveries (43%) at a gestational age of 32 weeks (29.5–32.5; P < 0.001). A median of 9 units of packed red blood cells (range: 4–16) was transfused with emergent delivery compared with 4.5 units (range: 1–7) with planned delivery (P = 0.05).
These findings suggest that planned late preterm delivery is reasonable for women with placenta previa and suspected PA who do not experience antepartum bleeding. Multiple episodes of antepartum bleeding or bleeding before 32 weeks of gestation among women with suspected accreta are associated with increased risk of emergent preterm delivery.