Mahomed 1989.

Methods	RCT. Modified factorial ‐ 2 x 3 x 2 design.
Participants	Setting: Southmead Hospital, Bristol. 1057 women needing perineal repair following delivery (all tears and episiotomies included). This was a subgroup of the main trial. Method of delivery: spontaneous or instrumental vaginal deliveries. Parity: primigravidae and multiparae. Mean age: group 1 = 26.0 years; group 2 = 25.9 years. Operators: midwives, senior house officers, registrars, consultants, medical students.
Interventions	Method of repair: described as below. Women divided into 2 groups. Group 1 (N = 524) vaginal trauma repaired with a continuous stitch, perineal muscle and skin sutured using the interrupted technique. 50% were repaired with Dexon (plus) 2/0 on a multipurpose needle and 50% were repaired with chromic catgut on a 35‐mm tapercut needle. Group 2 (N = 533) vaginal trauma repaired with a continuous stitch, perineal muscle apposed with interrupted stitches and skin sutured using the continuous subcuticular technique. 50% were repaired with Dexon (plus) 2/0 on a multipurpose needle and 50% were repaired with chromic catgut on a 35‐mm tapercut needle.
Outcomes	Included in analysis: short‐term pain at day 2 and 10; long‐term pain at 3 months; analgesia at day 2 and 10; re‐suturing at up to 3 months; dyspareunia at 3 months; removal of suture material at 3 months; resumption of intercourse at 3 months;
Notes	Method of repair: method described. Subcuticular technique was unpopular with some operators. Training period: not described. No interim analysis. Ethics Committee Approval. Pre‐set trial size had 80% chance of detecting significant clinical differences.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not clear.
Allocation concealment (selection bias)	Low risk	Serially numbered, sealed opaque envelopes (envelopes contained suture material and instructions for method of repair). 22 envelopes were unaccounted for.
Blinding (performance bias and detection bias) Clinical staff	High risk	Differences in suture materials and techniques.
Blinding (performance bias and detection bias) Women	High risk	Women may have been aware of suturing technique.
Blinding (performance bias and detection bias) Outcome assessors	High risk	Fully blind assessment was not possible owing to obvious differences in suture materials and techniques.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	1574 women randomised. 97% response rate at day 2, 86% at day 10 and 87% at 3 months (1366 women).
Other bias	Unclear risk	There were some protocol deviations; of those allocated to continuous sutures 18% had interrupted, only 2% of those allocated to interrupted had continuous sutures. "some midwives preferred the interrupted technique... sometimes a midwife called a senior house officer if the allocation was to subcuticular suturing".