INTRODUCTION The Management of Myelomeningocele Study, a.k.a. the MOMS trial, was published in 2011 in the New England Journal of Medicine. This prospective randomized controlled trial proved to be a milestone publication that provided definitive evidence that fetal surgery is a novel standard of care for select fetuses with spina bifida aperta (SB). The goal of our study is to assess whether our center can match these benchmark results. MATERIALS AND METHODS Our study was conducted according to the MOMS protocol using the same inclusion and exclusion criteria and looked at the same outcome parameters that were used in the MOMS trial. Zurich and MOMS results were compared. RESULTS We enrolled 20 patients between December 2010 and May 2015 all of whom underwent fetal surgery for SB. Among 51 different outcome variables, there were only 3 favorable (multiplicity-adjusted) significant differences (gestational age at birth, hindbrain herniation, and psychomotor development). There were no statistically significant differences regarding any other parameters. CONCLUSION Our findings confirm that rigorous apprenticeship, training, and comprehensive prospective data collection enable centers like the Zurich Center for Fetal Diagnosis and Therapy to achieve benchmark results for open fetal surgery for myelomeningocele and myeloschisis. These results justify the existence and continuation of our program. Outcome documentation is an essential element of quality management. It is medically and ethically fundamental for fetal medicine and surgery centers offering high-end innovative medical care.

• Hindbrain herniation is significantly more pronounced in myeloschisis than in myelomeningocele • Resolution of hindbrain herniation 4 weeks after in utero closure of ONTD • MRI is valuable for preoperative assessment and postoperative evaluation following in utero repair.

Our data suggest a positive effect of prenatal MMC closure on lower urinary tract function. The long-term significance of these results remains unclear. Therefore, continued close monitoring of renal and bladder function are mandatory.

Introduction: To compare tocolysis with magnesium sulfate versus atosiban regarding the occurrence of short-term preterm labor and maternal side effects during and after open fetal myelomeningocele (MMC) repair. Material and Methods: A prospective nonrandomized cohort study was performed including 30 fetal MMC cases. The first 15 cases (group 1) received magnesium sulfate according to the MOMS protocol. In the following 15 cases (group 2), magnesium sulfate was substituted by atosiban. Chorioamniotic membrane separation (CMS), premature prelabor rupture of the fetal membranes (PPROM), preterm delivery <3 weeks after fetal MMC repair, and maternal complications due to the tocolytic medication were the major endpoints. Results: In both groups, one CMS but no PPROM was diagnosed <3 weeks after fetal MMC repair. One patient of group 2 delivered <3 weeks after fetal MMC repair because of an intraoperative placental abruption at 25 weeks. All women of group 1 showed an electrolyte imbalance during magnesium sulfate administration. One woman of group 1 developed several episodes of a third-degree atrioventricular block within the first 3 days after fetal surgery. Lethargy was found in all women during magnesium sulfate therapy. No maternal side effects were found under atosiban. Discussion: The use of atosiban resulted in an almost identical short-term uterine outcome without any serious maternal complications as seen when magnesium sulfate was given. Thus, the authors suggest using atosiban instead of magnesium sulfate in the context of open fetal surgery.