Fetal Endoscopic Tracheal Occlusion (FETO) Trial for Congenital Diaphragmatic Hernia (CDH)

Inclusion Criteria: * Signed and dated consent * Stated willingness to comply with all study procedures and availability for the duration of the study * Singleton pregnancy * No pathogenic variants on microarray or pathologic findings on karyotype * Fetal echocardiogram with changes expected with CDH and no major structural cardiac defects * Fetal CDH (left or right) with severe pulmonary hypoplasia, defined as observed-to-expected (o/e) lung to head ratios (LHR) \<25% with liver up * Gestational age at FETO procedure: if o/e LHR \<25% will be done at 27 weeks plus 0 days to 29 weeks plus 6 days * Meets psychosocial criteria * Willing to reside within 30 minutes of Von Voigtlander Women's Hospital and ability to maintain follow up appointments * Patient has a support person (e.g. spouse, partner, friend, parent) that is available to stay with her for the duration of the pregnancy near Von Voigtlander Women's Hospital * Willing to comply with restrictions of daily living including inability to exercise, have intercourse, or return to work. Exclusion Criteria: * Multi-fetal pregnancy * History of latex allergy * History of preterm labor or incompetent cervix (requiring cerclage), short cervix (≤20mm), or uterine anomaly predisposing to preterm labor * Bilateral CDH, unilateral CDH with o/e LHR \> 25%, or unilateral CDH with o/e LHR \<25% but liver completely down in abdomen * Additional fetal or genetic abnormalities that would impact care after delivery or be known to have an impact on outcome * Maternal contraindications to elective fetoscopic surgery * Significant placental abnormalities (abruption, chorioangioma, accreta) known at time of enrollment and/or surgery * Maternal isoimmunization or neonatal alloimmune thrombocytopenia * Maternal HIV, Hepatitis B with positive surface antigen, Hepatitis C with presence of virus in maternal blood due to risk of fetal transmission during the procedure * No safe or feasible fetoscopic approach to balloon placement * Social work will meet with each patient to evaluate the social situation and support system. Identifiable issues of social instability or compliance with the protocol will exclude her as a potential candidate.