Banninger 1978.

Methods	Quasi‐randomised trial. Factorial design (3 arm trial, 2 arms compared different materials (polyglycolic acid vs catgut) using the same method of repair; the third arm included mixed materials and mixed methods of repair; we have not included this arm in the analyses).
Participants	Setting ‐ Zurich, Switzerland. 153 women ‐ these were women in 2 arms of a 3‐arm trial and included only those women who had the same suture material (either polyglycolic acid or catgut) and the same technique (as described below) used throughout the repair. Inclusion criteria ‐ women with an episiotomy and without complications. Exclusion criteria ‐ women with a past history of obstetric operations; breech deliveries and those with additional damage to the cervix, vagina and perineum. Parity ‐ primigravida (first‐time mothers). Mean age ‐ intervention group = 24.1; comparison group = 25.2. Operator ‐ doctors.
Interventions	Intervention group (n = 80) ‐ vagina, perineal muscle and skin sutured using the interrupted technique with polyglycolic acid (Dexon) No. 2‐0 on a 60 mm round bodied needle. Comparison group (n =73) ‐ vagina, perineal muscle and skin sutured using the interrupted technique with chromic catgut No. 0 on a 60 mm round bodied needle.
Outcomes	Short‐term pain ‐ day 3 and 7. Analgesia ‐ up to day 7. Suture dehiscence ‐ up to day 7. Resuturing ‐ up to day 7. Dyspareunia ‐ at 3 months.
Notes	Only one‐third of participants followed up at 3 months. Cosmetic results were reported at 3 months after delivery (data not included in the paper) ‐ the intervention group had less scarring in the form of 'rope ladder' compared to the comparison group.
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	High risk	Allocated by 'alternating sequence'.
Allocation concealment?	High risk	No information available regarding concealment of treatment allocation, but the alternating randomisation sequence means that group allocation may have been anticipated.
Blinding? Women	Unclear risk	No details given.
Blinding? Clinical staff	High risk	Difference in suture material appearance.
Blinding? Outcome assessors	High risk	Difference in suture material appearance.
Incomplete outcome data addressed? All outcomes	High risk	Low attrition for short‐term outcomes. At 3 months follow up only 30% of the original sample remained.
Free of other bias?	Unclear risk	No baseline imbalance apparent.