Mahony 1985.

Study characteristics
Methods	Single‐centre double‐blind randomized controlled trial
Participants	Inclusion criteria Birth weight between 700 g and 1300 g, admitted before 12 hours of age to the NICU Exclusion criteria Small for gestational age Presence of major congenital anomalies Evidence of congenital infection Platelet count < 75,000/µL Serum creatinine concentration >1.6 mg/dL (140 µmol/L) Echocardiographic evidence of structural heart disease Haematocrit <35% Permission refused or not requested due to mitigating social factors, and in the judgement of the attending neonatologist Moribund clinical condition
Interventions	Active intervention (n = 51) Blinded IV Indomethacin, first dose (given at 12 to 18 hours) was 0.2 mg/kg body weight and second dose (given 12 hours later) was 0.1 mg/kg and third dose (given 36 hours after the first) was 0.1 mg/kg. Control (n = 53) Blinded IV placebo
Outcomes	Relevant outcomes for this study included Mortality IVH NEC Treatment for symptomatic PDA Surgical PDA ligation
Notes	Primary study location: James Whitcomb Riley Hospital, Indiana, USA Study period: March 1982 to October 1983 Trial registration: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Infants were randomly allocated by a statistician otherwise uninvolved with the study, however the method of sequence generation was not specified.
Allocation concealment (selection bias)	Low risk	Allocation was concealed by placing identical vials of either indomethacin or placebo into envelopes
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Persons evaluating and caring for infants were unaware of study drug assignment.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Allocation of infants was not revealed until after discharge and outcome data collection was complete.
Incomplete outcome data (attrition bias) All outcomes	Low risk	6 infants were excluded from the analysis due to death before receiving all 3 doses of study drug. Outcomes were reported for all other randomized infants.
Selective reporting (reporting bias)	Unclear risk	We could not judge if there were any deviations from the protocol.
Other bias	Unclear risk	Study was stopped early due to lack of power to prove desired results; unclear if this was pre‐specified