Effect of oral castor oil on labor pain in post term pregnancy

Back ground and Post term pregnancy may lead to mortality in peri natal period and yet its mechanism is not clarified. Stress of absence of labor pain post partum infection physical damage due to macrosomia of the baby and bleeding due to atony of uterus are potential hazards which can be encountered in post term pregnancy. Many methods are available for induction of delivery. For example drugs, surgical and mechanical methods and alternative methods can be used to prevent post term pregnancy. Despite wide use of castor oil to initiate labor, the obstetric literature contains few studies about this botanical laxative. This study deals with the effect of oral castor oil, on the initiation of labor in post term pregnancy. This clinical trial included 30 pregnant women at≥41 weeks, experiencing their 2nd to 5th singleton pregnancy, without uterine contraction and a Bishop Score of 4 or less before intervention, and with no medical or obstetric problem. Patients were randomly assigned to experimental and control groups. Patients of experimental group received a single dose of castor oil (60 mL, PO), with fruit juice. Two groups were followed for 24 hours and were advised to avoid using enema, intercourse, laxatives, herbal, chemical or traditional drugs for induction of labor. Data were collected by means of interview, observation and delivery characteristics forms. Chi square, Fisher, exact and T-test were used for data analysis. The results of this study showed that labor pain was started earlier in experimental group than in control group (p=0.003). Mean Bishop Scores in experimental and control groups were 4.4±0.63 and 2.66±0.72 respectively. The length of the first stage of labor in experimental group was less than that of control group (p=0.002). The rate of normal delivery in experimental group was higher than that of control group (p=0.003). Labor pain begins earlier within 24 hours after taking caster oil.