Oxytocin agonists for preventing postpartum haemorrhage.

BACKGROUND

Postpartum haemorrhage (PPH) is one of the major contributors to maternal mortality and morbidity worldwide. Active management of the third stage of labour has been proven to be effective in the prevention of PPH. Syntometrine is more effective than oxytocin but is associated with more side-effects. Carbetocin, a long-acting oxytocin agonist appears to be a promising agent for the prevention of PPH.

OBJECTIVES

To determine if the use of oxytocin agonist is as effective as conventional uterotonic agents for the prevention of PPH, and assess the best routes of administration and optimal doses of oxytocin agonist.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (September 2006), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2006, Issue 2), MEDLINE (1966 to June 2006) and EMBASE (1974 to June 2006). We checked references of articles and communicated with authors and pharmaceutical industry.

SELECTION CRITERIA

Randomised controlled trials which compared oxytocin agonist (carbetocin) with other uterotonic agents or with placebo or no treatment for the prevention of PPH.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial quality.

MAIN RESULTS

Four studies (1037 women) were included in the review (three studies on caesarean delivery and one on vaginal delivery). The risk of PPH was similar in both oxytocin and carbetocin arms for participants who underwent caesarean delivery as well as participants, with risk factor(s) for PPH, who underwent vaginal delivery. Use of carbetocin resulted in a statistically significant reduction in the need for therapeutic uterotonic agent (relative risk (RR) 0.44, 95% confidence interval (CI) 0.25 to 0.78) compared to oxytocin for those who underwent caesarean section, but not for vaginal delivery. Carbetocin is also associated with a reduced need for uterine massage in both caesarean and vaginal deliveries (RR 0.38, 95% CI 0.18 to 0.80; RR 0.70, 95% CI 0.51 to 0.94) respectively. However, this outcome measure was only documented in one study on caesarean delivery and in the only study on vaginal delivery. Pooled data from the trials did not reveal any statistically significant differences in terms of the adverse effects between carbetocin and oxytocin.

AUTHORS' CONCLUSIONS: There is insufficient evidence that 100 micrograms of intravenous carbetocin is as effective as oxytocin to prevent PPH. In comparison to oxytocin, carbetocin was associated with reduced need for additional uterotonic agents, and uterine massage. There was limited comparative evidence on adverse events.