'TOTAL' (Tracheal Occlusion To Accelerate Lung Growth) Trial

This is a multi-center, non-blinded randomized controlled trial in fetuses with isolated
moderate CDH, i.e. moderate lung hypoplasia (as determined by prenatal assessment of lung
development). It essentially compares fetal therapy added to conventional postnatal care,
versus expectant prenatal management during pregnancy followed by conventional postnatal
care.

Enrollment:

Following completion of an inclusion/exclusion criteria checklist and obtaining informed
consent, the subject will be randomized into two groups ("FETO" and "expectant").

Procedures:

Group I: Standardized postnatal care (expectant group): mothers will be expectantly managed
during pregnancies and babies receive standardized postnatal care at a tertiary center used
to manage babies with CDH. The recommendation is that they adhere to consensus guidelines
published on the study website.

Group II: Prenatal intervention (FETO group): patients will undergo fetoscopic tracheal
occlusion and ideally prenatal reversal of the occlusion followed by standardized postnatal
care as in I. In this study FETO is to be done between 30 weeks plus 0 day and 31 weeks plus
6 days and removal of the balloon at 34 weeks plus 0 day to 34 weeks plus 6 days.

This study trial is a pragmatical or efficacy trial: ideally mothers will deliver after
removal of the balloon at those tertiary centers, typically offering postnatal care for the
patient involved. In group II (FETO-group), mothers will, in between placement and removal of
the balloon, thus carrying a fetus with obstructed airways, ideally remain under the care of
our local fetal treatment center (further referred to as FETO center). As many as possible
precautions are taken to avoid problems with balloon removal in case of earlier than expected
delivery.

- Balloons are to be electively removed prior to 35 weeks. FETO centers will provide 24/24
hours and 7/7 days services for management of fetuses with obstructed airways, either in
utero or during labor and delivery.

- Patients in the study and randomized to FETO, will be encouraged to stay near the FETO
center. After reversal of the occlusion the patient will be referred to the tertiary
care center where delivery and postnatal care will be undertaken. If the patient is not
remaining at or close to the FETO center, the postnatal treatment center should organize
likewise EXIT services.

Inclusion Criteria:

1. Patients aged 18 years or more, who are able to consent,

2. Singleton pregnancy,

3. Chromosomally normal fetus,

4. Gestation at randomization prior to 31 weeks plus 5 days or so that occlusion is done
at the latest on 31 weeks plus 6 days,

5. Fetus is estimated to have moderate pulmonary hypoplasia, defined prenatally as:

• O/E LHR 25-34.9% (included; irrespective of the position of the liver) • O/E LHR
35-44.9% (included) with intrathoracic liver herniation as determined by ultrasound or
MRI.

The O/E LHR will be determined by the FETO centers as follows:

- Measurement of the contralateral lung area preferentially by the tracing method
at the 4-chamber view of the heart; if by other method adjusted normative ranges
must be used.

- Measurement of the head circumference at the standard biparietal view of the head

- The observed lung area: calculation of the LHR as the ratio of the measurements
of the lung area to head circumference

- The expected lung area is the lung area of a normal gestational age match, as
determined by the head circumference of the index case in a normogram established
for the same measurement method (tracing method in this case). A calculator for
this will be available on the website of the study.

- Calculation of the observed over expected lung area,

6. Acceptance of randomization and the consequences for the further management during
pregnancy and thereafter, this includes the required observation following FETO
surgery, which lasts up to 4 weeks after balloon is in place,

7. The patients must undertake the responsibility for either remaining close to, or at
the FETO center, or being able to travel swiftly and within acceptable time interval
to the FETO center until the balloon is removed. Intended postnatal treatment center
must subscribe to suggested guidelines for "standardized postnatal treatment," and

8. Provide written consent to participate.

9. Fetus with no major anomalies that would impact the clinical course or outcomes.

Exclusion Criteria:

1. Maternal contraindication to fetoscopic surgery or severe medical condition in
pregnancy that make fetal intervention risky,

2. Technical limitations precluding fetoscopic surgery, such as severe maternal obesity,
uterine fibroids or potentially others, not anticipated at the time of writing this
protocol,

3. Preterm labor, cervix shortened (<15 mm at randomization) or uterine anomaly strongly
predisposing to preterm labor, placenta previa,

4. Patient age less than 18 years,

5. Psychosocial ineligibility, precluding consent,

6. Diaphragmatic hernia: right-sided or bilateral, major anomalies, isolated left-sided
outside the O/E LHR limits for the inclusion criteria, and

7. Patient refusing randomization, to comply with required 4-week observation after
balloon placement, or to comply with return to FETO center during the time period the
airways are occluded or for elective removal of the balloon.

8. Patient allergic to latex.