A randomised trial, conducted by midwives, of perineal repairs comparing a polyglycolic suture material and chromic catgut

Abstract

Objective: to assess the effect of suture materials (an absorbable synthetic suture material versus catgut) used in perineal repairs undertaken by midwives who had been trained and accredited in repair techniques. Design: randomised controlled trial. Setting: tertiary obstetric hospital in Australia. Participants: 391 women with a live singleton birth at ≥34 weeks gestation, resulting from a spontaneous vaginal delivery and who required perineal repair due to either an episiotomy or first or second degree tear. Intervention: eligible women were randomly allocated for repair with either polyglycolic acid or chromic catgut. Main outcome measures: perineal pain and dyspareunia up to six months postpartum. Findings:of the 194 women allocated to polyglycolic suture 106 (55%) were primipara compared with 79 (40%) of the 197 women allocated to catgut. Due to this unexplained imbalance, odds ratios were estimated with and without adjustment for parity. The parity-adjusted odds ratios were little changed (<11%) from the crude odds ratios. Although there were no statistically significant differences, parity-adjusted odds ratios (aOR) suggest that compared with women sutured with catgut, women sutured with polyglycolic were less likely to experience perineal pain at Day 3 postpartum (aOR=0.70 95% confidence interval [95% CI] 0.46–1.08) but by six months postpartum were somewhat more likely to experience perineal pain (aOR=1.77, 95% CI 0.57–5.47), dyspareunia (aOR=1.21 [0.62–2.33] and require removal of a suture (aOR=2.61 95% CI 0.59–12.41). Conclusions: the finding of reduced short-term perineal pain in women repaired with polyglycolic compared with catgut is similar to that of a Cochrane Systematic Review. The possibility that polyglycolic is associated with worse longer-term outcomes has not been previously reported but is biologically plausible (catgut causes a local inflammatory reaction but is rapidly absorbed, while polyglycolic causes little inflammation but absorption takes longer). This trial also illustrates the difficulties of undertaking clinical research in a busy delivery ward.