Miller, Jena L.

Importance Anhydramnios from fetal kidney failure causes lethal pulmonary hypoplasia. Serial amnioinfusions have shown promise in mitigating pulmonary disease from bilateral renal agenesis, but efficacy and safety for other causes of fetal kidney failure are unproven. Objective To assess the efficacy of serial amnioinfusions initiated before 26 weeks’ gestation to mitigate lethal pulmonary hypoplasia in cases of anhydramnios due to fetal kidney failure. Design, Setting, and Participants Prospective, nonrandomized clinical trial conducted at 13 US fetal therapy centers from December 2018 to February 2025. Outcomes for maternal-fetal pairs with anhydramnios before 22 weeks’ gestation due to fetal kidney failure without bilateral renal agenesis are reported; data collection for surviving infants continued until February 13, 2026. Exposure Thirty-two participants underwent serial amnioinfusions with isotonic fluid beginning before 26 weeks’ gestation. Main Outcomes and Measures The primary end point was neonatal survival for 14 days or longer with dialysis access placement. Secondary outcome measures of survival to discharge home and kidney transplant are reported. Results Twenty-nine of 32 participants (91%) had a live birth, with a median (IQR) gestational age at delivery of 34 weeks 1 day (31 weeks 5 days to 34 weeks 6 days). All participants delivered before 37 weeks’ gestation. No unexpected serious maternal adverse events occurred, and the most common maternal complications were preterm prelabor rupture of membranes in 19 participants (56%) and chorioamniotic separation in 10 (29%). The primary outcome occurred in 19 (65.5%) of 29 live-born neonates (95% CI, 45.7%-82.1%). Factors associated with survival to the primary outcome included receiving more amnioinfusions (median [IQR], 14 [9-18] in survivors vs 7 [4-11] in nonsurvivors; P = .01), longer time interval from first amnioinfusion to preterm prelabor rupture of membranes (63.5 [60.5-74.5] days in survivors vs 29.0 [22.0-56.0] days in nonsurvivors; P = .01), gestational age greater than 32 weeks (79% of survivors vs 38% of nonsurvivors; P = .03), and higher birth weight (2029 [1770-2250] g in survivors vs 1635 [1185-1915] g in nonsurvivors; P = .01). Fourteen live-born infants (48%) survived to hospital discharge at a median (IQR) age of 4.7 (3.4-5.7) months. Of the 11 infants surviving to date, 7 (64%) have undergone kidney transplant between ages 2 years to 5 years. Conclusions and Relevance Serial amnioinfusions mitigated lethal pulmonary hypoplasia in neonates with anhydramnios due to fetal kidney failure. Significant neonatal morbidity and mortality independent of early lung function was noted. Factors associated with survival were consistent with the Renal Anhydramnios Fetal Therapy trial’s bilateral renal agenesis cohort, suggesting common mechanistic pathways for mitigating pulmonary hypoplasia. Trial Registration ClinicalTrials.gov Identifier: NCT03101891

BACKGROUND AND OBJECTIVES: Myelomeningocele is defined by the presence of a fluid-filled sac that contains the neural placode and cerebrospinal fluid (CSF) at the level of the spinal defect. Alternatively, the term myeloschisis is used when the neural placode is not contained within a CSF-filled sac. While both are eligible for prenatal closure, few studies have characterized the impact of the type of lesion on postnatal outcomes. This study compares the outcomes of these 2 types of open spinal dysraphism using data from the Fetal Myelomeningocele Consortium registry sponsored by the North American Fetal Therapy Network. METHODS: The prospective observational Fetal Myelomeningocele Consortium registry was used to extract deidentified data corresponding to patients who underwent fetal closure of myelomeningocele vs myeloschisis. Demographics, operative characteristics, perioperative complications, and postnatal outcomes were collected. RESULTS: A total of 1327 patients were identified, including 991 (74.7%) with myelomeningocele and 336 (25.3%) with myeloschisis. Compared with myelomeningocele, myeloschisis was associated with lower rates of prenatal talipes (11% vs 24%, P < .001) and higher rates of favorable prenatal movement (94% vs 86%, P < .001). Postnatally, myeloschisis conferred higher rates of leg movement (97% vs 90%, P = .002) and an increased likelihood of ambulation in the household (10.4% vs 4.1%, P = .009) and outside (7.2% vs 1.9%, P = .004) at 1 year. However, myeloschisis was also linked to greater use of skin patches during closure (49% vs 27%, P < .001), higher CSF leak rates among those with wound dehiscence (26% vs 8%, P = .014), and more frequent CSF diversion and tethered cord surgeries at follow-up. CONCLUSION: Myeloschisis and myelomeningocele demonstrate distinct clinical profiles. Although patients with myeloschisis may have favorable motor outcomes, they are also characterized by higher rates of CSF leakage, CSF diversion, and tethered cord surgery. These findings highlight the need for lesion-specific prognostication and may inform surgical planning and parental counseling in the context of prenatal spina bifida closure.

BACKGROUND AND OBJECTIVES: The Management of Myelomeningocele Study established a role for maternal-fetal surgery for myelomeningocele (MMC) but was limited to patients with a maternal body mass index (BMI) less than 35 kg/m 2 . However, as the rate of obesity has increased globally, some centers have extended the Management of Myelomeningocele Study criteria to include patients with a BMI of 35 to 40 kg/m 2 . We used the Fetal MMC Consortium registry to analyze the complications associated with maternal-fetal surgery in patients with a maternal BMI < 35 kg/m 2 compared with 35 to 40 kg/m 2 . METHODS: The prospective observational Fetal MMC Consortium registry sponsored by the North American Fetal Therapy Network was used to extract deidentified “maternal complication” and “fetal/neonatal complication” data sets, corresponding to patients with complete entries related to maternal or fetal/neonatal complications, respectively. Demographics, clinical characteristics, and complications were recorded. Propensity score matching was conducted with a 2:1 algorithm, and outcomes were compared between patients with BMI < 35 kg/m 2 and those with BMI 35 to 40 kg/m 2 . RESULTS: Propensity score matching resulted in 156 patients with BMI < 35 kg/m 2 and 78 patients with BMI 35 to 40 kg/m 2 in the “maternal complication” data set, and 130 patients with BMI < 35 kg/m 2 and 65 patients with BMI 35 to 40 kg/m 2 in the “fetal/neonatal complication” data set. No significant differences in the median number of maternal (2.0 vs 2.0; P = .257) or median number of fetal/neonatal (1.0 vs 1.0; P = .409) complications were observed between the 2 cohorts. Furthermore, prematurity rates did not differ significantly between the BMI < 35 and BMI 35 to 40 cohorts. CONCLUSION: Maternal-fetal surgery for open neural tube defect closure is not associated with increased risks among patients with a maternal BMI of 35 to 40 kg/m 2 . Extending the initial inclusion criteria for prenatal MMC closure has the potential to expand access to patients with a higher risk for open neural tube defects.

Abstract Objective In utero fetal spina bifida repair decreases the risk for cerebrospinal fluid (CSF) diversion including ventriculoperitoneal (VP) shunt placement, reverses hindbrain herniation, and improves motor function with a higher likelihood of independent ambulation. Unfortunately, in utero surgery can be complicated by preterm delivery. The goal of this study was to compare pregnancy and neonatal outcomes between individuals who delivered very preterm, and those who delivered later in gestation following in utero spina bifida repair. Methods Data from the North American Fetal Therapy Network Fetal Myelomeningocele Consortium Registry collected from 2011 to 2024 were analyzed. Three cohorts of patients were categorized by gestational age at delivery and compared: <30 weeks, 30–34 weeks, and >34 weeks. Comparisons between groups for maternal and delivery outcomes were completed for the entire cohort and then analyzed for those with available CSF diversion data up to 1 year of life. Chi‐square or Fisher's exact tests were used to compare categorical variables, and Kruskal–Wallis tests were used to determine if there are significant differences between the distributions of the three groups. A p ‐value <0.05 was considered significant. Results A total of 1213 patients were analyzed (<30 weeks, n = 111 [9.2%]; 30–34 weeks, n = 323 [26.6%]; >34 weeks, n = 779 [64.2%]). Overall fetal and neonatal mortality was 2.2%, 85% of which occurred in the <30‐week cohort, where perinatal mortality was 21%. Latency from fetal surgery to delivery averaged 2.1 weeks for the <30‐week group. Rates of abruption, chorioamnionitis, and spontaneous labor were higher in the <30‐week group compared to later gestational age cohorts. Neonatal morbidity was also significantly higher in the <30‐week cohort for sepsis, apnea, respiratory distress, patent ductus arteriosus, intraventricular hemorrhage, and periventricular leukomalacia in the <30‐week cohort. CSF diversion data were available for 677 neonates (<30 weeks, n = 53; 30–34 weeks, n = 186; >34 weeks, n = 438). There was no significant difference in VP shunt placement between the different gestational age groups. Conclusion Very preterm birth following in utero spina bifida repair results in significant perinatal mortality and neonatal morbidity. Delivery prior to 30 weeks of gestation occurs in 9% of patients after in utero spina bifida repair, resulting in a 21% perinatal mortality rate. However, even among those who delivered very preterm, a reduction in VP shunt rates, a benefit of in utero repair, appears to be preserved. Further data are warranted to assess the impact of prematurity following in utero surgery on ambulation and developmental outcomes.

This survey study reports on use of renal replacement therapy, hemodynamic support, sedation, neuroimaging, and extracorporeal membrane oxygenation at Renal Anhydramnios Fetal Therapy trial sites for neonates with either bilateral renal agenesis or fetal kidney failure.

ImportanceEarly anhydramnios during pregnancy, resulting from fetal bilateral renal agenesis, causes lethal pulmonary hypoplasia in neonates. Restoring amniotic fluid via serial amnioinfusions may promote lung development, enabling survival.ObjectiveTo assess neonatal outcomes of serial amnioinfusions initiated before 26 weeks’ gestation to mitigate lethal pulmonary hypoplasia.Design, Setting, and ParticipantsProspective, nonrandomized clinical trial conducted at 9 US fetal therapy centers between December 2018 and July 2022. Outcomes are reported for 21 maternal-fetal pairs with confirmed anhydramnios due to isolated fetal bilateral renal agenesis without other identified congenital anomalies.ExposureEnrolled participants initiated ultrasound-guided percutaneous amnioinfusions of isotonic fluid before 26 weeks’ gestation, with frequency of infusions individualized to maintain normal amniotic fluid levels for gestational age.Main Outcomes and MeasuresThe primary end point was postnatal infant survival to 14 days of life or longer with dialysis access placement.ResultsThe trial was stopped early based on an interim analysis of 18 maternal-fetal pairs given concern about neonatal morbidity and mortality beyond the primary end point despite demonstration of the efficacy of the intervention. There were 17 live births (94%), with a median gestational age at delivery of 32 weeks, 4 days (IQR, 32-34 weeks). All participants delivered prior to 37 weeks’ gestation. The primary outcome was achieved in 14 (82%) of 17 live-born infants (95% CI, 44%-99%). Factors associated with survival to the primary outcome included a higher number of amnioinfusions (P = .01), gestational age greater than 32 weeks (P = .005), and higher birth weight (P = .03). Only 6 (35%) of the 17 neonates born alive survived to hospital discharge while receiving peritoneal dialysis at a median age of 24 weeks of life (range, 12-32 weeks).Conclusions and RelevanceSerial amnioinfusions mitigated lethal pulmonary hypoplasia but were associated with preterm delivery. The lower rate of survival to discharge highlights the additional mortality burden independent of lung function. Additional long-term data are needed to fully characterize the outcomes in surviving neonates and assess the morbidity and mortality burden.Trial RegistrationClinicalTrials.gov Identifier: NCT03101891