Safety and Efficacy of Fetoscopic Endoluminal Tracheal Occlusion in Congenital Diaphragmatic Hernia

Inclusion Criteria: * Pregnant person age 18 years or older * Singleton pregnancy * Normal fetal karyotype with confirmation by culture results, Chromosomal Microarray (CMA) with non-pathological variants, Whole Exome Sequencing (WES) or Whole Genome Sequencing (WGS). Results by florescence in situ hybridization (FISH) will be acceptable if the patient is \>26 weeks gestation * Gestational age at enrollment less than 29 weeks 6 days * Intrathoracic liver herniation * Isolated left Congenital Diaphragmatic Hernia (CDH) with Lung to Head Circumference Ratio (LHR) \<30% at enrollment OR isolated right CDH with LHR \<= 45% at enrollment * Cervical length by transvaginal ultrasound \>= 20 mm within 24 hours of FETO procedure * Psychosocial criteria * Able to provide informed consent Exclusion Criteria: * Patient \< 18 years of age * 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 or placenta previa * Psychosocial ineligibility precluding consent * Inability to reside within 30 minutes of OHSU * Inability to comply with the travel for the follow-up requirements of the trial * Lack of a support person (e.g., spouse, partner, mother) available to stay with the patient for the duration of the pregnancy at OHSU. * Bilateral CDH, isolated left sided CDL with LHR \>= 30% or isolated right side CDH wit…