BACKGROUND The Management of Myelomeningocele Study (MOMS) eligibility criteria preclude in utero surgery for fetal spina bifida (fSB) when the maternal body mass index (BMI) is ≥35 kg/m2. Some centers still respect this criterion, while others, like ours, do not. This study aimed to assess whether maternal and fetal safety is compromised with higher maternal BMIs. METHODS Data of 192 patients with open fSB repair at our center were retrospectively analyzed. According to their BMI, patients were divided into three groups: group 1 (BMI <30 kg/m2), group 2 (BMI 30-35 kg/m2), and group 3 (BMI >35 kg/m2). Subgroup analysis was performed to assess differences in maternal and fetal outcomes. Additionally, complications were divided into grades 1 to 5 according to their severity and outcome consequences and compared among groups. RESULTS Out of 192 patients, 146 (76.0%) had a BMI <30 kg/m2, 28 (14.6%) had a BMI 30-35 kg/m2, and 18 (9.4%) had a BMI >35 kg/m2. Significant differences occurring more often in either group 2 or 3 compared to group 1 were maternal wound seroma (50% or 56% vs. 32%, p = 0.04), amniotic fluid leakage (14% or 6% vs. 2%, p = 0.01) as well as vaginal bleeding (11% or 35% vs. 9%, p = 0.01). On the contrary, duration of tocolysis with atosiban was shorter in patients with BMI >30 kg/m2 (4 or 5 vs. 6 days, p = 0.01). When comparing severity of maternal or fetal complications, grade 1 intervention-related complications occurred significantly more often in group 3 compared to group 1 or 2 (78% vs. 45% or 57%, p = 0.02). Gestational age at delivery was around 36 weeks in all groups without significant differences. CONCLUSIONS This investigation did not identify clinically relevant maternal and/or fetal outcome problems related to BMIs >35 kg/m2. Additional studies are however needed to confirm our results.