Pregnancy outcomes for women with placenta previa in relation to the number of prior cesarean deliveries

OBJECTIVE: To estimate the association between the number of prior cesarean deliveries and pregnancy outcomes among women with placenta previa. METHODS: Women with a placenta previa and a singleton gestation were identified in a concurrently collected database of cesarean deliveries performed at 19 academic centers during a 4-year period. Maternal and perinatal outcomes were analyzed after stratifying by the number of cesarean deliveries before the index pregnancy. RESULTS: Of the 868 women in the analysis, 488 had no prior cesarean delivery, 252 had one prior cesarean delivery, 76 had two prior cesarean deliveries, and 52 had at least three prior cesarean deliveries. Multiple measures of maternal morbidity (eg, coagulopathy, hysterectomy, pulmonary edema) increased in frequency as the number of prior cesarean deliveries rose. Even one prior cesarean delivery was sufficient to increase the risk of an adverse maternal outcome (a composite of transfusion, hysterectomy, operative injury, coagulopathy, venous thromboembolism, pulmonary edema, or death) from 15% to 23%, which corresponded, in multivariable analysis, to an adjusted odds ratio of 1.9 (95% confidence interval 1.2-2.9). Conversely, gestational age at delivery and adverse perinatal outcome (a composite measure of respiratory distress syndrome, necrotizing enterocolitis, intraventricular hemorrhage grade 3 or 4, seizures, or death) were unrelated to the number of prior cesarean deliveries. CONCLUSION: Among women with a placenta previa, an increasing number of prior cesarean deliveries is associated with increasing maternal, but not perinatal, morbidity. LEVEL OF EVIDENCE: II.