Effect and Safety of Castor Oil on Labor Induction and Prevalence of Vaginal Delivery: A Systematic Review and Meta Analysis

Atefeh Amerizadeh, Ziba Farajzadegan, Sedigheh Asgary


Background: Castor oil is used in some countries to induce labor, but results on its effectiveness and safety is controversial. This systematic review and meta‑analysis aimed to evaluate the effect of castor oil on labor induction and prevalence of vaginal delivery along with investigating its safety.

Materials and Methods: PubMed, Scopus, Web of Science, and Google Scholar were searched systematically up to September 2020. Observational studies and Randomized Clinical Trials (RCTs), which assessed the effect of castor oil on labor induction in English and Persian languages using different combinations of the related key terms and Medical Subject Headings (MeSH) terms were collected and analyzed independently by two authors. Random effect model was used for meta‑analysis. The studies were included in which the Relative Risk (RR) had been reported with 95% Confidence Intervals (CIs).

Results: A total of 12 studies consisting 1653 pregnant women were included. The mean age of women who used castor oil was 24.72 years and in control group was 24.67 years. Results showed that labor induction was significantly higher in castor oil group than control group (RR: 3.27; 95% CI (1.96, 5.46)). Prevalence of vaginal delivery was 81% in the castor oil group and 69% in the control group.

Conclusions: It can be concluded that use of castor oil has positive effect on labor induction and increases the prevalence of vaginal delivery. None of the studies considered in this meta‑analysis reported any serious harmful effects for the use of castor oil.


Castor, Labor, Induced, obstetric labor, oil

Full Text:



Caughey AB, Sundaram V, Kaimal AJ, Cheng YW, Gienger A, Little SE, et al. Maternal and neonatal outcomes of elective induction of labor. Evid Rep Technol Assess (Full Rep) 2009:1 257.

Marconi AM. Recent advances in the induction of labor. F1000Res 2019;8:F1000 Faculty Rev 829.

Hall HG, McKenna LG, Griffiths DL. Complementary and alternative medicine for induction of labour. Women Birth 2012;25:142 8.

Vogel JP, Osoti AO, Kelly AJ, Livio S, Norman JE, Alfirevic Z. Pharmacological and mechanical interventions for labour induction in outpatient settings. Cochrane Database Syst Rev 2017;9:CD007701.

McKeon T. Castor (Ricinus communis L.). USA AOCS Press. 2016. p. 75-112.

Kelly AJ, Kavanagh J, Thomas J. Castor oil, bath and/or enema for cervical priming and induction of labour. Cochrane Database Syst Rev 2013;2013:CD003099.

Garry D, Figueroa R, Guillaume J, Cucco V. Use of castor oil in pregnancies at term. Altern Ther Health Med 2000;6:77 9.

Boel ME, Lee SJ, Rijken MJ, Paw MK, Pimanpanarak M, Tan SO, et al. Castor oil for induction of labour: Not harmful, not helpful. Aust N Z J Obstet Gynaecol 2009;49:499 503.

Gilad R, Hochner H, Vinograd O, Saam R, Hochner Celnikier D, Porat S. 148: The CIC Trial–castor oil for induction of contractions in post term pregnancies. Am J Obstetr Gynecol 2012;206:S77 8.

Kozhimannil KB, Johnson PJ, Attanasio LB, Gjerdingen DK, McGovern PM. Use of nonmedical methods of labor induction and pain management among U.S. women. Birth 2013;40:227 36.

Hall HG, McKenna LG, Griffiths DL. Midwives’ support for

complementary and alternative medicine: A literature review. Women Birth 2012;25:4 12.

Boltman Binkowski H. A systematic review: Are herbal and homeopathic remedies used during pregnancy safe? Curationis 2016;39:1514.

Davis L. The use of castor oil to stimulate labor in patients with premature rupture of membranes. J Nurse Midwifery 1984;29:366 70.

Kahnamoyiagdam F, Aghamohammadi M, Rostamnejad M. The effect of castor oil on the induction of labor: A clinical trial. Nurs Midwifery J 2014;12:348 53.

Neri I, Dante G, Pignatti L, Salvioli C, Facchinetti F. Castor oil for induction of labour: A retrospective study. J Matern Fetal Neonatal Med 2018;31:2105 8.

Zamawe C, King C, Jennings HM, Mandiwa C, Fottrell E. Effectiveness and safety of herbal medicines for induction of labour: A systematic review and meta analysis. BMJ Open 2018;8:e022499.

Moher D, Liberati A, Tetzlaff J, Altman DG. Preferred reporting items for systematic reviews and meta analyses: The PRISMA statement. PLoS Med 2009;6:e1000097.

Stang A. Critical evaluation of the Newcastle Ottawa scale for the assessment of the quality of nonrandomized studies in meta analyses. Eur J Epidemiol 2010;25:603 5.

Higgins JP, Altman DG, Gøtzsche PC, Jüni P, Moher D, Oxman AD, et al. The Cochrane Collaboration’s tool for assessing risk of bias in randomised trials. BMJ 2011;343:d5928.

Higgins JP, Thompson SG, Deeks JJ, Altman DG. Measuring inconsistency in meta analyses. BMJ 2003;327:557 60.

Egger M, Davey Smith G, Schneider M, Minder C. Bias in meta analysis detected by a simple, graphical test. BMJ 1997;315:629 34.

DerSimonian R, Laird N. Meta analysis in clinical trials. Control Clin Trials 1986;7:177 88.

DeMaria AL, Sundstrom B, Moxley GE, Banks K, Bishop A, Rathbun L. Castor oil as a natural alternative to labor induction: A retrospective descriptive study. Women Birth 2018;31:e99 104.

Abd El Gawad S. Castor oil safety and effectiveness on labour induction and neonatal outcome. J Biol Agric Healthcare 2014;4:1 10.

Azhari S, Pirdadeh S, Lotfalizadeh M, Shakeri MT. Evaluation of the effect of castor oil on initiating labor in term pregnancy. Saudi Med J 2006;27:1011 4.

Gilad R, Hochner H, Savitsky B, Porat S, Hochner Celnikier D. Castor oil for induction of labor in post date pregnancies: A randomized controlled trial. Women Birth 2018;31:e26 31.

Montazeri S, Afshary P, Souri H, Iravani M. Efficacy of castor oil for induction and augmentation of labor. Iran J Pharm Res 2010;3(Suppl 2):38 9.

Okoro O, Ugwu E, Dim C, Ozumba B, Nkwo P, Leonard A, et al. Effectiveness of castor oil in preventing post term pregnancy in low resource setting: A randomized controlled trial. Am J Clin Med Res 2019;7:37 43.

Pirdadeh Beiranvand S, Azhari S, Lotfalizadeh M, Shakeri M. The effect of castor oil on initiating labor in 40 42 weeks pregnancy. J Babol Univ Med Sci 2007;9:33 8.

Saberi F, Abedzadeh M, Sadat Z, Eslami A. Effect of castor oil on induction of labor. KAUMS J (FEYZ) 2008;11:19 23.

Iravani M, Montazeri S, Afshari P, Souri H. A study on the safety and efficacy of castor oil for cervical ripening and labour induction. Jundishapur Sci Med J 2006;5:398 404.

Mathias JR, Martin JL, Burns TW, Carlson GM, Shields RP. Ricinoleic acid effect on the electrical activity of the small intestine in rabbits. J Clin Invest 1978;61:640 4.

Burdock GA, Carabin IG, Griffiths JC. Toxicology and pharmacology of sodium ricinoleate. Food Chem Toxicol 2006;44:1689 98.

Ammon HV, Thomas PJ, Phillips SF. Effects of oleic and ricinoleic acids on net jejunal water and electrolyte movement. Perfusion studies in man. J Clin Invest 1974;53:374 9.

Tunaru S, Althoff TF, Nüsing RM, Diener M, Offermanns S. Castor oil induces laxation and uterus contraction via ricinoleic acid activating prostaglandin EP3 receptors. Proc Natl Acad Sci U S A 2012;109:9179 84.


  • There are currently no refbacks.