Fetal Endoscopic Tracheal Occlusion (FETO) for Severe Congenital Diaphragmatic Hernia

Inclusion Criteria:

   - Maternal Age: 18-50

   - Singleton gestation

   - Gestational age before 29 weeks 6 days

   - Severe left or right-sided CDH: For severe left sided CDH observed-to-expected
   lung-to- head ratio (o/e LHR) less than 25% between 22 and 29 6/7 weeks' gestation,
   liver herniation, MRI lung volumes less than 30% expected based on gestational age
   nomograms. For severe right sided CDH o/e LHR less than 30 % between 22 and 29 6/7
   weeks' gestation, liver herniation, MRI lung volumes less than 30% expected based on
   gestational age nomograms.

   - Normal genetic karyotype or microarray testing by amniocentesis or chorionic villus
   sampling (CVS)

   - Absence of associated fetal structural cardiac anomalies by a dedicated fetal
   echocardiogram

   - Absence of other structural anomalies by ultrasound or MRI

   - Appropriate multi-disciplinary counseling performed with maternal-fetal medicine,
   neonatology, pediatric surgery, genetics, pediatric otolaryngology (ENT).

   - Must be willing to remain near LPCH Stanford (within 30 minutes from the hospital) for
   the duration of the balloon placement.

   - No maternal and/or fetal contra-indications to fetal surgery such as a bleeding
   disorder, poorly controlled diabetes or hypertension, short cervix (measuring < 20mm),
   risk for preterm birth etc.

   - Planned pregnancy surveillance at LPCH Stanford

   - Planned delivery at LPCH Stanford

   - Able to provide written consent

   - Willingness to comply with all study procedures and availability (meets psychosocial
   criteria) for the duration of the study including having a support person

Exclusion Criteria:

   - Contraindications to fetal surgery including poorly controlled hypertension, diabetes
   or other maternal medical condition including hematological disorder

   - High risk for preterm labor and/or delivery based on either significant history of
   preterm birth, short cervix (measuring < 20mm), significant uterine anomaly or other
   risk factor, incompetent cervix (requiring cerclage)

   - Non-isolated CDH - CDH with additional structural anomalies

   - Significant maternal obesity defined as a body mass index (BMI) greater than 40. BMI
   is a calculation which includes a person's height and weight

   - History of natural rubber latex allergy

   - Uterine anomaly such as large or multiple fibroids or mullerian duct abnormality

   - Participation in another intervention study that influences maternal and fetal
   morbidity and mortality.

   - Bilateral CDH, left-sided CDH with O/E LHR >25%, or left-sided CDH with O/E LHR <25%
   but liver completely down in abdomen

   - Right-sided CDH O/E LHR >30% or right-sided CDH with O/E LHR <30% with liver
   completely down in abdomen

   - Significant placental abnormalities (abruption, chorioangioma, accreta) known at the
   time of enrollment and/or surgery

   - Maternal-fetal Rhesus isoimmunization, Kell sensitization or neonatal alloimmune
   thrombocytopenia, affecting the current pregnancy.

   - 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.