Maternal inclusion criteria: - Singleton pregnancy - Gestational age at screening is 19 to 25 5/7 weeks and gestational age at surgery is 22 to 25 6/7 weeks - Maternal age: 18 years and older - Body mass index < 40 kg/m2 - No preterm birth risk factors (short cervix, history of previous preterm delivery) - No previous uterine incision in the active uterine segment - Willing to undergo an open fetal repair if the fetoscopic approach is unsuccessful Fetal inclusion criteria: - Spina bifida defect between T1 to S1 vertebral levels - Chiari II malformation - No evidence of kyphosis (curved spine) - No major life-threatening fetal anomaly unrelated to spina bifida - Normal karyotype, or normal CMA, or a CMA with variants of unknown significance

Maternal exclusion criteria: - Non-resident of the United States - Multifetal pregnancy - Poorly controlled insulin-dependent pregestational diabetes - Poorly controlled A2DM insulin-dependent diabetes - Current or planned cerclage or documented history of an incompetent cervix - Placenta previa or placental abruption - Short cervix of < 20 mm - Obesity as defined by a body mass index of > 40 kg/m2 - Previous spontaneous singleton delivery prior to 37 weeks - Maternal-fetal Rh isoimmunization, Kell sensitization, or a history of neonatal alloimmune thrombocytopenia - HIV or Hepatitis-B positive status - Known Hepatitis-C positivity - Uterine anomaly such as large or multiple fibroids or a mullerian duct abnormality that is diagnosed via imaging prior to surgery, which that are unavoidable during surgery - Other medical conditions which are contraindication to surgery or general anesthesia - Patient does not have a support person - Inability to comply with the travel and follow-up requirements of the trial - Patient does not meet psychosocial standardized assessment criteria - Participation in this or another intervention study that influences maternal and fetal morbidity and mortality - Maternal hypertension - Zika virus positivity - Allergy/history of drug reaction to Amphotericin B Fetal exclusion criteria: - Major fetal anomaly not related to spina bifida - Kyphosis in the fetus of 30 degrees or more - Ventriculomegaly greater than 15 mm and no movements noted at hip and knee joints