What are the novel findings of this work? This is the largest follow-up study to date evaluating the postnatal mortality and 30-month outcome of children who underwent fully percutaneous fetoscopic repair of myelomeningocele (MMC). What are the clinical implications of this work? Intrauterine repair of MMC by percutaneous fetoscopy, and via hysterotomy, result in a remarkably good outcome concerning mortality, prematurity, shunt-placement rates, motor and mental development and free ambulation, when compared to postnatal repair.