Fetal Endoscopic Tracheal Occlusion for Congenital Diaphragmatic Hernia

Inclusion Criteria: * Singleton pregnancy * Normal fetal karyotype or microarray. Results by fluorescence in situ hybridization (FISH) will be acceptable if the patient is \> 26 weeks * Isolated severe left CDH with O/E LHR \< 25% ) * Gestation age at enrollment prior to 29 wks plus 6 days. * Pulmonary hypoplasia with ultrasound O/E LHR \< 25% (measured at 18 0/7 to 29 5/7 weeks) at the time of surgery. * Gestational age at FETO procedure 27 weeks 0 days to 29 weeks 6 days as determined by clinical information (LMP) and evaluation of first ultrasound * Patient meets psychosocial criteria: able to reside within 30 minutes of Mayo Clinic, Rochester and able to comply with the travel for the follow-up requirements of the trial; patient has a support person (e.g. spouse, partner, mother) available to stay with the patient for the duration of the pregnancy at Mayo Clinic * Patient is willing and able to give informed consent * Appropriate multi-disciplinary counseling performed with maternal-fetal medicine, neonatology, pediatric surgery, genetics, pediatric otolaryngology (ENT) Exclusion Criteria: * Multi-fetal pregnancy * History of natural rubber latex allergy * Preterm labor, cervix shortened (\<20 mm) at enrollment or within 24 hours of FETO balloon insertion procedure) or uterine anomaly strongly predisposing to preterm labor * Psychosocial ineligibility, precluding consent: inability to reside within 30 minutes of Mayo Clinic, Rochester and inability to comply with the t…