Effectiveness of Castor Oil in Preventing Post-term Pregnancy in Low Resource Setting: A Randomized Controlled Trial

Castor oil has long been used as a way of inducing labor and preventing post-term pregnancy. However, its safety and effectiveness has not been conclusive thereby necessitating the need for further studies. This article evaluated the effectiveness of single oral dose of castor oil at 40-41 weeks of gestation for prevention of post-term pregnancy, in a low resource setting. This was a randomized controlled trial of pregnant women attending antenatal care clinic at the University of Nigeria Teaching Hospital Enugu, Nigeria. The eligible participants were randomized into two groups; group A (intervention group) received oral castor oil (60mls) and group B (control group) did not receive castor oil. The intervention group had a lower incidence of post term pregnancy compared to the control group (18/105(17.1%) vs 44/106(41.5%), RR= 0.41, NNT= 4). The proportion of women requiring formal induction of labor with misoprostol or with oxytocin was significantly lower in the intervention group than in the control group (18/105 (17.1%) vs 44/106(41.5%), RR= 0.41, NNT= 4). The intervention group were less likely to have their labor augmented with oxytocin compare to the control 41/87(47.1%) vs 44/62(71.0%), RR 0.66, NNT 4). The route of delivery and the need for new born special care unit admission were similar in the two groups. There was no significant difference in the maternal complications due to castor oil in the two groups. Single oral dose of Castor oil administration significantly lowers the incidence of post- term pregnancy, without higher risk of maternal and/ or neonatal complications.