Hanigan 1988.

Study characteristics
Methods	Single‐centre randomized controlled trial
Participants	Inclusion criteria birth weight of <1500 g, negative sonogram for PVH‐IVH and written parental consent. Exclusion criteria Gestational age >34 weeks Platelet counts of <60,000/mm3 Clinical evidence of a bleeding diathesis Significant congenital abnormalities Lack of a baseline cranial sonogram obtained before 12 hours of age Birth weight less than 500 g
Interventions	Active intervention (n = 56) Blinded IV indomethacin as reconstituted lyophilized sodium salt; 0.1mg/kg at <12 hours, and 24, 48 and 72 hours IV, over 2 minutes Control (n = 55) Blinded IV placebo (Placebo identical quantity of saline solution)
Outcomes	Relevant outcomes for this study included Mortality IVH Treatment for symptomatic PDA
Notes	Primary study location: Illinois, USA Study period: 1 May 1984 to 30 April 1986 Trial registration: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of sequence generation was not specified.
Allocation concealment (selection bias)	Low risk	Used random‐sized block allocation, and opaque sealed envelopes available only by the pharmacist
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Personnel involved in care were blinded to participants' study arm
Blinding of outcome assessment (detection bias) All outcomes	Low risk	States that only biostatistician and pharmacist had access to study arms, implying that outcome assessors were also blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	11 infants enrolled were withdrawn from study before statistical analysis, six due to oliguria or thrombocytopenia, one withdrew consent, four due to false‐negative baseline sonograms. No enrolled infants were unaccounted for.
Selective reporting (reporting bias)	Unclear risk	Study protocol unavailable, unclear if there were any deviations to the original protocol.
Other bias	Low risk	None noted