Oboro 2003.

Methods	RCT (individual randomisation) 2‐arm trial.
Participants	Setting: 4 district government hospitals in Nigeria. Data collection 2000 to 2001. 1077 women requiring perineal repair after episiotomy or second‐degree tears (women with first‐ or third‐degree tears were excluded). Operators: over 75% repairs by midwives. Parity: both primi‐ and multiparous women included. Mean age: group 1 (2‐layer technique) = 26.3 years; group 2 (3‐layer technique) = 26.2 years.
Interventions	Group 1: 2‐stage approach (not clear) but with the skin left unsutured using number 00 chromic catgut or polyglycolic sutures. Group 2: 3‐stage approach (not clear) with skin closure with interrupted or subcuticular continuous sutures (the subcuticular technique was encouraged) using number 00 chromic catgut or polyglycolic sutures.
Outcomes	Included in analysis: perineal pain (at 48 hours, 2, 6 and 12 weeks' postpartum); analgesia use (at 48 hours, 2, 6 and 12 weeks' postpartum); wound gaping (< 0.5 cm) (at 48 hours, 2, 6 and 12 weeks' postpartum); wound breakdown (at 2 weeks' postpartum); suture removal (2, 6 and 12 weeks' postpartum); re‐suturing (6 and 12 weeks' postpartum); dyspareunia (deep and superficial) (6 and 12 weeks' postpartum); resumption of pain‐free intercourse (6 weeks' postpartum); time taken to carry out the repair (minutes).
Notes	Suture techniques not clearly described. Not clear what materials were used and whether there were any differences in materials in different arms of the trial
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation when women completed the third stage of labour. Envelopes were prepared by "a statistician using computer generated block randomisation with varying block sizes".
Allocation concealment (selection bias)	Low risk	Sequentially numbered opaque sealed envelopes.
Blinding (performance bias and detection bias) Clinical staff	High risk	Different techniques.
Blinding (performance bias and detection bias) Women	High risk	Noy clear, although women would be aware from the appearance of the wound whether or not the skin had been sutured.
Blinding (performance bias and detection bias) Outcome assessors	High risk	Technique used would be apparent to assessors who carried out an examination of the perineum to assess gaping and bruising.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	1077 randomised, 823 completed both the 2 and 6 weeks questionnaires (approximately 20% attrition for longer‐term outcomes), loss to follow‐up balanced across groups. The level of missing data was not clear in the results tables.
Other bias	Unclear risk	No baseline imbalance apparent.