Comparative Study of the Effect of Vaginal use of Primrose Oil with Misoprostol on Cervical Preparation of Prim Gravid Women: A Double-blind Clinical Trial

BACKGROUND: This study compares the effect of vaginal administration of evening primrose oil with misoprostol on cervical preparation in prim gravid women at ≥40 weeks gestation. MATERIALS AND METHODS: This was a double-blind randomized clinical trial conducted in Isfahan, Iran during 2019-2020 on 110 prim gravid pregnant women with a gestational age of 40 weeks and more and cephalic presentation of the fetus with the obstetrical indication for pregnancy termination. After obstetric examinations to rule out cephalo pelvic disproportion and calculation of the Bishop score by the researcher, patients were randomized to receive 25 μg misoprostol tablets (n = 55) or 1000 mg evening primrose oil Pearls (n = 55) administrated vaginally by a midwife. We compared Bishop's score before and after the intervention, time of cervical ripening, a dose of intervention for cervical ripening, need to induce labor, the interval between cervical preparation and induction of labor, duration of oxytocin use, need for cesarean section, and its cause, Apgar score at 5 and 10 minutes, neonatal birth weight. RESULTS: Mean baseline Bishop Score was not significant between the groups (P = 0.45); after the intervention, it was significantly higher in the primrose oil group (P < .001). Significantly fewer patients required cesarean sections in the primrose oil group (P = 0.03). The other outcomes were. not significant between the groups (P > 0.05). CONCLUSION: Misoprostol and primrose oil administration appear to positively affect cervical readiness. Primrose oil resulted in significantly better Bishop Scores and fewer cesarean sections compared to misoprostol in pregnancy 40 weeks and more.