Greenberg 2004.

Methods	RCT (block randomisation).
Participants	Setting ‐ Brigham & Women's Hospital and the Massachusetts General Hospital, USA. 1361 women enrolled ‐ only two‐thirds (n = 908) required suturing of vulval and/or vaginal laceration; and/or episiotomy. Inclusion criteria ‐ women presenting in labour or for induction. Exclusion criteria ‐ not documented. Parity ‐ primigravida and multigravida Maternal age ‐ not documented. Operator ‐ obstetricians and midwives.
Interventions	Method of repair ‐ (not fully described) all practitioners used subcuticular skin closure except 1 operator who used interrupted technique. Intervention group (n = 459) ‐ fast‐absorbing polyglactin 910 (gauge of material and needle size not specified). Comparison group (n = 449) ‐ chromic catgut (gauge of material and needle size not specified).
Outcomes	INCLUDED IN ANALYSIS Vaginal pain ‐ 24 ‐ 48 hrs; 10‐14 days; 6‐8 weeks postpartum. Uterine pain ‐ 24 ‐ 48 hrs; 10‐14 days; 6‐8 weeks postpartum. Analgesia (used in last 8 hrs) 24 ‐ 48 hrs; 10‐14 days; 6‐8 weeks postpartum. Painless bowel movement ‐ 24 ‐ 48 hrs; 10‐14 days; 6‐8 weeks postpartum. Resuturing ‐ up to day 7. Perineal wound breakdown at 6‐8 weeks. Dyspareunia ‐ at 3 months.
Notes	87% of participants received allocated suture material.
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Low risk	Treatment allocated by block randomisation (block size 10) using validated SAS program (Cary, NC).
Allocation concealment?	Low risk	Numbered opaque sealed envelopes.
Blinding? Women	High risk	Stated that 'women were not blinded to suture material used'.
Blinding? Clinical staff	High risk	Unable to ‘blind’ operators due to obvious difference in suture material.
Blinding? Outcome assessors	Unclear risk	Stated 'nurses were blinded to suture material used when asking questions at 24‐48 hrs and 10‐14 days postpartum'.
Incomplete outcome data addressed? All outcomes	Unclear risk	1361 women randomised, however, only 908 women required perineal repair and were included in analysis. Intention‐to‐treat analysis carried out amongst women who received sutures (women were recruited prior to delivery and therefore some women did not require perineal suturing). 64% of participants were lost to follow up at 6‐8 weeks postpartum.
Free of other bias?	Unclear risk	Groups appeared similar at baseline. There were some protocol violations but analysis by randomisation group for those women requiring repair.