Castor Oil Ingestion and Balloon Catheter for Labor Induction in Multiparous

The goal of this randomized controlled trial is to examine the efficacy of combining castor oil ingestion with extra-amniotic single balloon catheter for cervical ripening on time from induction to delivery in multiparous women.

The main question it aims to answer are:

Does the addition of the use of castor oil to extra-amniotic single balloon reduce the time until birth? Does the addition of the castor oil affect other perinatal outcomes during childbirth? Are the side effects of the castor tolerated by the mothers? Participants will be randomly divided into 2 groups: the study group will drink a mixture of 60 ml of castor oil mixed with 140 ml of orange juice. Thirty minutes later, extra-amniotic single balloon catheter will be inserted above the internal cervical os and filled with 60 mL of normal saline.

In the control group, the catheter will be inserted into cervical canal without ingestion of castor oil.

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).

Eligibility Criteria:
Inclusion Criteria:

* Women above 18 years old
* Sign an informed consent
* Term pregnancy (\>37 weeks)
* Viable fetus
* Singleton
* Vertex presentation
* Intact membranes
* Cervix with Bishop score ≤6

Exclusion Criteria:

* Previous cesarean delivery
* Major fetal malformations
* Contraindication to spontaneous vaginal delivery
* Amniotic fluid index \>25cm
* Chorioamnionitis at admission
* Placental abruption
* Previous prostaglandin use for induction of labor
* A low-lying placenta (up to 2 cm from the internal os)
* Carriers of hepatitis B or C or human immunodeficiency viruses,
* Women with a history of allergy to latex.
* Women with a history of allergy to castor oil