Fetal Endotracheal Occlusion (FETO) in the Resolution of Pulmonary Hypertension in Fetuses With Severe CDH

Inclusion Criteria: * Patient is a pregnant woman between 18 and 45 years of age * Singleton pregnancy * The fetuses will be 28+0/7 to 31+6/7 weeks of gestational age * Confirmed diagnosis of severe left- or right-sided CDH of the fetus: Observed/expected total lung volume equal to or less than 0.32 with more than 21% of liver herniated into the hemithorax. (Ideally calculated between 28+0/7 and 31+6/7 weeks' gestation.) * Normal fetal echocardiogram or echocardiogram with a minor anomaly (such a small VSD) that in the opinion of the pediatric cardiologist will not affect postnatal outcome * Normal fetal karyotype or microarray * The mother must be healthy enough to have surgery * Patient and father of the baby provide signed informed consent that details the maternal and fetal risks involved with the procedure * Patient willing to remain in Houston for the duration following balloon placement until delivery. Exclusion Criteria: * Contraindication to abdominal surgery, fetoscopic surgery, or general anesthesia * Allergy to latex * Allergy or previous adverse reaction to a study medication specified in this protocol * Preterm labor, preeclampsia, or uterine anomaly (e.g., large fibroid tumor) in the index pregnancy. * Fetal aneuploidy, known structural genomic variants, other major fetal anomalies that may impact the fetal/neonatal survival or known syndromic mutation * Suspicion of major recognized syndrome (e.g. Fryns syndrome) on ultrasound or MRI * Maternal BMI \>40 * High risk for fetal hemophilia