My last post looked at acupuncture as a method of inducing labour ‘naturally’, let’s now look at oils – most commonly evening primrose oil and castor oil.
** DISCLAIMER: this is an examination of the current literature only. Please do not try any of these methods (or anything else that would be considered stupid!) without first discussing with your own healthcare provider **
A study carried out at The West Virginia University School of Medicine in the States documented the use of herbal preparations for cervical ripening, induction, and augmentation of labor by certified nurse-midwives (CNMs) and nurse-midwifery education programs. A whole lot of data was collected but of interest evening primrose oil was the most common herbal preparation discussed in nurse-midwifery education programs, and castor oil was the most commonly used herbal preparation used by nurse-midwives in clinical practice.
Castor oil is in fact one of the oldest drugs – orally, it has a laxative effect and allegedly induces labour in pregnant females. It does this via EP(3) prostanoid receptors which are specifically activated by ricinoleic acid.
I know you’re thinking ‘blah blah blah, just tell me if it works!”
One study carried out in Thailand looked at the safety and effectiveness of castor oil for induction of labour in pregnancies with an ultrasound estimated gestational at birth of more than 40 weeks. It found that castor oil for induction of labour had no effect on time to birth nor were there any harmful effects observed in this large series.
A Cochrane review looked at 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. It found a lack of trials addressing the role of castor oil as an induction agent and as such, could not comment on the efficacy of castor oil as an induction agent.
Another study carried out at Monash University in Melbourne, Australia looked at the scientific evidence for the use of complementary and alternative medicine to stimulate labour. THey found that castor oil and evening primrose oil might not be effective and possibly increase the incidence of complications.
Bottom line: there is very limited literature either for or against the use of oils in the induction of labour. Considering these studies together, it seems that oils are commonly used, however their use may be associated with complications (certainly there are anecdotal reports of women who have taken castor oil, resulting in strong uterine contracts and the bub opening his/her bowels (meconium) in utero. Not so good.
McFarlin BL, Gibson MH, O’Rear J, Harman P. A national survey of herbal preparation use by nurse-midwives for labor stimulation. Review of the literature and recommendations for practice. J Nurse Midwifery. 1999 May-Jun;44(3):205-16.
Hall HG, McKenna LG, Griffiths DL. Complementary and alternative medicine for induction of labour. Women Birth. 2012 Sep;25(3):142-8. doi: 10.1016/j.wombi.2011.03.006. Epub 2011 Apr 27.
Tunaru S, Althoff TF, Nüsing RM, Diener M, Offermanns S. Castor oil induces laxation and uterus contraction via ricinoleic acid activating prostaglandin EP3 receptors. 2012 Jun 5;109(23):9179-84. doi: 10.1073/pnas.1201627109. Epub 2012 May 21.
Boel ME, Lee SJ, Rijken MJ, Paw MK, Pimanpanarak M, Tan SO, Singhasivanon P, Nosten F, McGready R. Castor oil for induction of labour: not harmful, not helpful. Aust N Z J Obstet Gynaecol. 2009 Oct;49(5):499-503. doi: 10.1111/j.1479-828X.2009.01055.x.
Kelly AJ, Kavanagh J, Thomas J. Castor oil, bath and/or enema for cervical priming and induction of labour. Cochrane Database Syst Rev. 2001;(2):CD003099.