Maternal laparotomy to fetoscopic myelomeningocele repair in patients with Class 2 obesity is safe and feasible.

BACKGROUND: There is minimal to no data on fetal surgery outcomes in the setting of body mass index (BMI) ≥ 35. Theoretical concerns exist for increased maternal risks from surgery and increased surgical difficulty due to maternal body habitus. OBJECTIVE: To evaluate the pregnancy and operative outcomes with maternal laparotomy to 3-port fetoscopic myelomeningocele (MMC) repair in the setting of pre-pregnancy BMI 35-40 compared with pre-pregnancy BMI < 35. METHODS: This was a cohort study at a single maternal fetal care center in which maternal laparotomy to 3-port fetoscopic surgery for MMC was performed. Criteria for offering surgery were same as the Management of Myelomeningocele Study (MOMS) Trial with the exception that, starting in 2022, our center's BMI criterion was increased to include pre-pregnancy BMI ≤ 40. The primary outcome was the gestational age of delivery after surgery. Secondary outcomes planned were operative times, birthweight, and postoperative maternal and fetal complications. Evaluation of non-inferiority was planned on the primary outcome and operative times, with a < 1 week decrease in gestational age at delivery in the setting of repair with BMI ≥ 35 being considered non-inferior. RESULTS: From January 2022 to December 2024, there were a total of 38 pregnancies that both underwent maternal laparotomy to fetoscopic MMC repair and delivered prior to December 2024. A total of 12 patients had a pre-pregnancy BMI 35-40. Patients were similar regarding pregnancy characteristics. Regarding the primary outcome, there was no difference in gestational age at delivery between groups (36 2/7 weeks, IQR 34 3/7, 37 5/7 in BMI 35-40 vs. 35 2/7 weeks, IQR 31 4/7, 37 4/7 in BMI < 35, p = 0.257). The primary outcome was determined to be non-inferior with a 95% CI (34 2/7 to 37 6/7), being not inclusive of 34 3/7 minus 1 week (pre-specified acceptable difference). While times for the fetoscopic surgery were similar between groups, there was a significant increase in operative time of the non-fetoscopic portions of the case with BMI 35-40 (80 min, IQR 63, 91 vs. 59 min, IQR 55, 71, p = 0.047) and non-inferiority could not be established for overall operative times. However, this did not translate to increased postoperative complications, as other postoperative factors were consistent between groups. CONCLUSION: Maternal laparotomy to fetoscopic MMC repair patients with BMI 35-40 is non-inferior to that of patients with BMI < 35. With the exception of a slightly longer non-fetoscopic surgery time, the characteristics and pregnancy outcomes are similar between groups. BMI 35-40 should not by itself be considered an absolute contraindication to in utero MMC repair.