Nowadays, more and more women embark on pregnancy with previous Caesarean scar. One in five pregnancies requires induction of labour. The use of non-pharmacological methods (methods without using medication) has been gaining popularity for women who are not good candidates, such as women with previous Caesarean scar, for induction with medications such as prostaglandin. Labour induction with prostaglandin carries a higher risk of uterine rupture and thus it is not routinely offered to women with previous Caesarean delivery in Cairo University Hospital. Non-pharmacological methods of induction of labour appear to be safe in women with previous Caesarean delivery. However, various methods are available and the efficacy among them remain in doubt.

In Cairo University Hospital, castor oil, which is a type of induction methods, is routinely offered to women with previous Caesarean delivery who require induction of labor. However, castor oil may not exert its labor induction effect immediately and the delivery may be delayed by up to 8 days. This may render a proportion of women resort to repeated Caesarean section for failed induction. Castor oil is traditionally given by midwives in order to induce labor.

The investigators are intent to recruit 70 healthy pregnant women with a history of previous one cesarean section and with no contraindication to trial of labor after cesarean . Women will be randomly and blindly divided into equal-sized intervention group and control group. Intervention group will be given a single dose 60 mL of castor oil in 140 mL of orange juice, while control group will be given a placebo with similar texture. Primary outcomes to be tested are the percentage of women entering active labor within 24 hours of castor oil or placebo administration and the number of successful vaginal deliveries after cesarean.

Inclusion Criteria:

• Pregnant women with one previous lower segment Caesarean section who are admitted to Cairo University Hospital for induction of labor (IOL) will be recruited. The inclusion criteria are age at least 20 years old, gestational age at recruitment from 36 weeks to 38 weeks ±6 days, gestational age at induction= 39 weeks, singleton pregnancy, reassuring fetal status, and Bishop score ≤ 6.

Exclusion Criteria:

• Prior high-risk uterine scar; uterine rupture, classical CS, hysterotomy, or myomectomy
• Short inter-delivery interval (<12 months)
• Complications in the previous CS (e.g. puerperal sepsis)

Obstetric indication for CS (either elective or emergency):

• Placenta praevia
• Placental abruption
• Documented evidence of cephalopelvic disproportion
• Fetal macrosomia (estimated fetal weight >4 kg)
• Fetal anomalies interfering with vaginal delivery e.g. hydrocephalus
• Fetal distress or non-reassuring Cardiotocography pattern