Castor Oil Ingestion and Balloon Catheter for Labor Induction in Multiparous

The rate of labor induction has increased up to 25.7% in 2018 for several demographic and obstetric reasons. Various methods are used to induce labor worldwide, including natural, mechanical and pharmacological agents. of all methods balloon catheters were proven to cause fewer adverse perinatal events. Though induction is considered a safe and effective procedure, it may lead to a prolonged labor which is associated with complications such postpartum hemorrhage, infection, and operative delivery. Based on these data several studies have examined the combinations of balloon catheters with other pharmacological agents on labor durations. The results were inconsistent, and several reports showed that the combination reduced significantly the length of labor. Nevertheless, pharmacological agents may be associated with adverse events including uterine hyperstimulation, placental abruption, and postpartum hemorrhage, though the overall risk is small. Castor oil, extracted from the seeds of Ricinus communis plant, is a natural effective substance for induction of labor. it's considered a safe and inexpensive though the exact mechanism by which it induces labor is still unclear. Our hypothesis suggests that ingestion of castor oil combined with the balloon catheter will shorten the time to delivery. In order to show a reduction by 2 hours, a sample size of 98 in each group will be needed assuming 80% power and a two-tailed alpha of 5%. Since the success rate of vaginal delivery was nearly 95% according to the same report, the sample size was calculated to 103 women in each group. Additional 5% are planned to be recruited to account for trial drop out for any reason, yielding a total final sample size of 108 women in each group (216 in both groups).