Open in-utero fetal surgery is not without risk and the NICHD study (MOMS Trial) showed an elevation in maternal-fetal morbidity/risk when compared to the postnatally treated group, including higher risk for chorioamniotic separation (26% vs. 0%, respectively), maternal pulmonary edema (6% vs. 0%), oligohydramnios (21% vs. 0%), placental abruption (6% vs. 0%), spontaneous membrane rupture (46%; RR: 6.15; 95% CI: 2.75-13.78), spontaneous labor (38%; RR: 2.80, 95%CI: 1.51-5.18), maternal blood transfusion (9%; RR: 7.18; 95%CI: 0.90-57.01), and preterm delivery before 34 weeks (46%; RR: 9.2; 95%CI: 3.81-22.19). The reason for the increased incidence of these complications is related to the nature of the open fetal procedure, which involves a multi-faceted invasive approach including maternal laparotomy, large hysterotomy with uterine edge stapling, and open fetal repair of the spina bifida defect that may involve manipulation and exposure of the fetus for a significant amount of time.