Castor oil, bath and/or enema for cervical priming and induction of labour

Background

Castor oil, a potent cathartic, is derived from the bean of the castor plant. Anecdotal reports, which date back to ancient Egypt have suggested the use of castor oil to stimulate labour. Castor oil has been widely used as a traditional method of initiating labour in midwifery practice. Its role in the initiation of labour is poorly understood and data examining its efficacy within a clinical trial are limited. This is one of a series of reviews of methods of cervical ripening and labour induction using standardised methodology.

Objectives

To determine the effects of castor oil or enemas for third trimester cervical ripening or induction of labour in comparison with other methods of cervical ripening or induction of labour.

Search strategy

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (May 2003) and bibliographies of relevant papers. We updated this search on 13 August 2009 and added the results to the awaiting classification section.

Selection criteria

Clinical trials comparing castor oil, bath or enemas used for third trimester cervical ripening or labour induction with placebo/no treatment or other methods listed above it on a predefined list of labour induction methods.

Data collection and analysis

A strategy was developed to deal with the large volume and complexity of trial data relating to labour induction. This involved a two-stage method of data extraction.

Main results

In the one included study of 100 women, which compared a single dose of castor oil versus no treatment, no evidence of a difference was found between caesarean section rates (relative risk (RR) 2.31, 95% confidence interval (CI) 0.77, 6.87). No data were presented on neonatal or maternal mortality or morbidity. There was no evidence of a difference between either the rate of meconium stained liquor (RR 0.77, 95% CI 0.25 to 2.36) or Apgar score less than seven at five minutes (RR 0.92, 95% CI 0.02 to 45.71) between the two groups. The number of participants was small hence only large differences in outcomes could have been detected. All women who ingested castor oil felt nauseous (RR 97.08, 95% CI 6.16 to 1530.41).

Authors' conclusions

The only trial included in this review attempts to address the role of castor oil as an induction agent. The trial was small and of poor methodological quality. Further research is needed to attempt to quantify the efficacy of castor oil as an induction agent.

[Note: The three citations in the awaiting classification section of the review may alter the conclusions of the review once assessed.]