Couser 1996.

Study characteristics
Methods	Single‐centre randomized controlled trial
Participants	Inclusion criteria Preterm infants 23 to 29 weeks GA; 600 g to 1250 g BW; received prophylactic surfactant in delivery room Exclusion criteria Congenital anomalies Parental refusal Inability to obtain parental consent within first 24 hours of life Infants with small muscular ventricular septal defects and congenital heart disease were later excluded following diagnosis in echo
Interventions	Active intervention (n = 43) Prophylactic IV indomethacin sodium trihydrate (Indocin) 0.1mg/kg every 24 hours for 6 doses slow IV infusion over 20 minutes; initiated within 24 hours of birth Control (n = 47) IV placebo (0.9% saline solution given at same times as indomethacin treatment group)
Outcomes	Relevant outcomes for this study included Neurodevelopmental impairment including cerebral palsy at 36 months corrected age Clinically significant PDA IVH grade 3 or 4 Mortality Chronic lung disease (supplementary oxygen at 28 days plus chest Xray changes) NEC Urine output reduced to < 1.0 mL/kg/hour at any time during first 7 days
Notes	Primary study location: Abbott‐Northwestern Hospital and Children's Health Care,,Minneapolis, USA Study period: 3 June 1994 to 18 Oct 1995 Trial registration: Not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of sequence generation not described.
Allocation concealment (selection bias)	Unclear risk	Unclear if allocation was concealed.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Individuals administering the treatment were blinded, staff examining and caring for infants were blinded. Hospital pharmacists prepared blinded indomethacin and blinded placebo.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Cardiologists blinded to patient assignment and not involved in patient management. Examiners blinded to patient assignment.
Incomplete outcome data (attrition bias) All outcomes	Low risk	All 93 enrolled infants accounted for (3 excluded due to ventricular septal defect before analysis).
Selective reporting (reporting bias)	Unclear risk	Study protocol unavailable for comparison
Other bias	Low risk	Appeared free of other bias.