Researchers, from the University of Calgary, have reviewed and provided a meta-analysis of clinical trials on induction of labour to evaluate whether induction affects the risk of caesarean section in women with intact membranes (where the amniotic sac has not yet ruptured).
The rising caesarean section rates across North America and Europe continue to be a major concern for medical professionals and one factor that provides conflicting evidence and advice is induction of labour. This paper aims to address this by comparing clinical trials on induction with expectant management in pregnant women.
There were 37 Randomised Controlled Trials (RCTs) identified through online databases for analysis. There were 27 trials that included uncomplicated pregnancies (37-42 weeks gestation) and 10 covering pregnancies that were complicated with diabetes, suspected macrosomia, twins or at a high risk score for caesarean section.
Only three trials documented statistically significant differences in caesarean section rates between a policy of induction and expectant management, two reported reductions with one reporting an increase in risk.
While the remaining trials reported non-significant differences in caesarean section rates, based on further analysis of the combined results the researchers suggest the overall caesarean section risk was lower by approximately 17% with induction of labour. This further meta-analysis of 31 trials determined that a policy of induction was associated with a moderate but statistically significant reduction in the risk of caesarean section compared to expectant management.
The authors conclude that further clinical trials are needed to look at elective induction for women at a high risk of caesarean section.
Stephen Wood, Department of Obstetrics and Gynaecology, University of Calgary and co-author of the paper, said:
“Induction of labour is one of the most common interventions in obstetrics and it is widely held that limiting induction will reduce caesarean section rates. Our analysis suggests that this may not be the case.
“However, it should be noted that the differences in caesarean section risk may have occurred due to factors other than induction and that more trials are needed to address whether labour induction would benefit women at high risk for caesarean section such as older or obese mothers.”
Mike Marsh, BJOG Deputy-Editor-in-Chief added:
“Recent literature on induction of labour and its effects on the risk of caesarean section is conflicting.
“Induction of labour is performed for a number of reasons, some because of a condition that puts the mother and fetus at immediate risk, but in some women the condition is less severe and the immediate risk is less.
“Clinicians’ concerns about fetal and maternal wellbeing may increase the risk of caesarean section during an induction. In some women not inducing labour and waiting until a condition becomes worse may increase this concern and the risk of caesarean section in labour.
“This is a high quality review that managed to analyse studies of induction of labour for a broad range of conditions. It suggests that induction does not always lead to an increase in caesarean section rates, and should prompt further studies of the effects of induction on caesarean section rates in the management of each specific condition.”
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Please include a link to the paper in online coverage: http://dx.doi.org/10.1111/1471-0528.12328
Stephen Wood, Stephanie Cooper, Sue Ross. Does induction of labour increase the risk of caesarean section? A systematic review and meta-analysis of trials in women with intact membranes. BJOG 2013 http://dx.doi.org/10.1111/1471-0528.12328