Feto-Endoscopic Tracheal Occlusion (FETO) for Severe Congenital Diaphragmatic Hernia

Inclusion Criteria: * Isolated CDH with liver up * Severe pulmonary hypoplasia with ultrasound O/E LHR \<25% at the time of surgery * Gestational age at FETO procedure 27 weeks 0 days to 29 weeks 6 days * Moderate pulmonary hypoplasia with ultrasound O/E LHR \<30% and liver-up at the time of surgery * Gestational age at FETO procedure 30 weeks 0 days to 31 weeks 6 days in this moderate category * Maternal age greater than or equal to 18 years * Gestational age at enrollment prior to 29 weeks 6 days, or 31 weeks 6 days in moderate category * Normal karyotype or FISH * Normal fetal echocardiogram * Singleton pregnancy * Willing to remain in the greater Cincinnati area for remainder of pregnancy * Family considered and decline option of termination of the pregnancy at less than 24 weeks 0 days * Family meets psychosocial criteria Exclusion Criteria: * Patient \< 18 years old * Multi-fetal pregnancy * Rubber latex allergy * Preterm labor, cervix shortened (\<15 mm) or uterine anomaly strongly predisposing to preterm labor, placenta previa * Bilateral CDH, isolated left sided CDH with an O/E \> 30% * Additional fetal anomaly by ultrasound, MRI, or echocardiogram * Chromosomal abnormalities * Maternal contraindications to fetoscopic surgery or severe maternal condition in pregnancy * Incompetent cervix with or without a cerclage * Placental abnormalities known at time of enrollment * Maternal HIV, Hepatits B, Hepatitis C * Maternal uterine anomaly * No safe or technically feasible fetoscopic approach to balloon placement * Participation in another intervention study that influences maternal and fetal morbidity and mortality or participation in this trial in a previous pregnancy