Groom 2005.

Methods	Randomised controlled trial.
Participants	98 singleton pregnancies at high risk for preterm labour. Recruitment started from GA of 16 weeks up to 26 weeks. Setting: 2 teaching hospitals in London, UK. Inclusion criteria: at least 1 of the following: at least 2 previous second trimester losses or early preterm deliveries < 30 weeks; 1 previous second trimester loss or early preterm birth < 30 weeks and cervical length ≤ 15 mm from 14 to 24 weeks; cervical changes requiring cerclage in current pregnancy determined either by ultrasound criteria or clinically (rescue cerclage). Exclusion criteria: multiple pregnancy, previous allergy to NSAIDs, maternal renal dysfunction.
Interventions	Pregnant women in the study group received rofecoxib 12.5 mg once daily and in control group received placebo. Duration of treatment was not reported. Treatment completed at 32 weeks of GA.
Outcomes	Change in amniotic fluid index and oligohydramnios. Change in hourly fetal urine production rate. Change in ductus arteriosus pulsatile index and maximum systolic velocity. Discontinuation owing to change in renal function/ductal blood flow. PPROM. GA at PPROM. Non‐compliance. Duration of treatment. Iatrogenic preterm birth. Preterm birth before GA 24 weeks. Delivery before GA 37 weeks. GA at delivery. Adverse effects. Neonatal discharged home alive and well. Birthweight. Route of delivery. Major postpartum haemorrhage. SCBU admission. Days in SCBU. Requiring ventilation. Neonatal head scan with IVH, periventricular flare and evidence of calcification. PDA. Mild tricuspid regurgitation/mild pulmonary hypertension. NEC.
Notes	‐
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Stratified randomisation to ensure equal numbers with cerclage assigned to each group was done using computer‐generated randomisation program.
Allocation concealment (selection bias)	Low risk	Treatment and placebo were prepared in identical gelatin‐covered capsules and issued by a pharmacist independent to the investigators.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Treatment and placebo were prepared in identical gelatin‐covered capsules and issued by a pharmacist independent to the investigators.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Treatment and placebo were prepared in identical gelatin‐covered capsules and issued by a pharmacist independent to the investigators.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Outcomes of all of the participants in the study were reported. There were no losses to follow‐up or drop‐outs.
Selective reporting (reporting bias)	Unclear risk	Both positive and negative outcomes were reported; however, we could not assess the protocol.
Other bias	Low risk	None known. Baseline characteristics of 2 groups were comparable.

GA: gestational age; IVH: intraventricular haemorrhage; NEC: necrotising enterocolitis; NSAID: non‐steroidal anti‐inflammatory drug; PDA: patent ductus arteriosis; PPROM: preterm premature rupture of membranes; SCBU: special care baby unit.