Fetal Endoscopic Tracheal Occlusion for Congenital Diaphragmatic Hernia (FETO)

Inclusion Criteria: * Singleton pregnancy * Normal fetal karyotype with confirmation by culture results. Results by fluorescence in situ hybridization (FISH) will be acceptable if the patient is \> 26 weeks. * Isolated Left CDH with liver up * Gestation age at enrollment prior to 29 wks plus 6 days severe pulmonary hypoplasia with ultrasound (US) O/E lung area to head circumference ratio (LHR) \< 25% (measured at 180 to 296 weeks) at the time of surgery; O/E LHR 25% to \<30% (measured at 300 to 316 weeks) at time of surgery. * Gestational age at FETO procedure with O/E LHR \<25% at 27 weeks 0 days to 29 weeks 6 days; with O/E LHR 25% to \<30% at 30 weeks 0 days to 31 weeks 6 days as determined by clinical information (LMP) and evaluation of first ultrasound * Patient meets psychosocial criteria Exclusion Criteria: * Multi-fetal pregnancy * History of natural rubber latex allergy * Preterm labor, cervix shortened (\<15 mm at enrollment or within 24 hours of FETO balloon insertion procedure) or uterine anomaly strongly predisposing to preterm labor, placenta previa * Psychosocial ineligibility, precluding consent: * Inability to reside within 30 minute drive of our hospital, and inability to comply with the travel for the follow-up requirements of the trial * Patient does not have a support person (e.g. spouse, partner, mother) available to stay with the patient for the duration of the pregnancy at our institution. * Right sided CDH or bilateral CDH, isolated left sided with…