Harrison 2003.

Methods	RCT.
Participants	Women with left‐sided CDH at 22‐28 weeks' gestation, with LHR < 1.4, with normal fetal echo and karyotype.
Interventions	Laparotomy and fetoscopic insertion of tracheal balloon, delivery by EXIT procedure at > 36 weeks in tertiary centre. Vaginal delivery planned unless CS required for obstetric indications. Standard care group was treated expectantly, with a planned return to the treating centre at 36 weeks of gestation, Antenatal steroids were administered if there was preterm labour or if the lung profile indicated immaturity. If spontaneous labour did not occur, labour was induced. Delivery was vaginal unless CS was indicated.
Outcomes	Primary = survival to 90 days, need for ECMO, duration of ventilatory support, oxygen therapy, GI morbidity, neurological morbidity, survival to discharge, duration of hospital stay, maternal physical and psychological morbidity.
Notes	Most outcomes for the primary report are reported as treatment actually received, although the Keller report of infant pulmonary function reported intention‐to‐treat analyses. Conducted in the United States. This research was funded by a grant (R01 HL62433) from the National Institute of Child Health and Human Development, National Institutes of Health (to Dr. Albanese), by the Nicholson Fund, and by Glaser Pediatric Research Network.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described.
Allocation concealment (selection bias)	High risk	2 women randomly assigned to fetal tracheal occlusion opted to have standard care.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not described.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not described.
Incomplete outcome data (attrition bias) All outcomes	High risk	Some analysis performed/reported by actual treatment received, not intention‐to‐treat.
Selective reporting (reporting bias)	Unclear risk	Unable to make judgement.
Other bias	Unclear risk	Trial was terminated early based on data monitoring board recommendation that unlikely to detect difference with planned enrolment.