Comparison of the Effect of Misoprostol and Evening Primrose oil Capsules with Misoprostol on Delivery Method in Post-Term Pregnancy: Clinical Trial

 Post-term pregnancies are pregnancies that last more than 42 full weeks (294 days) from the first day of the last menstrual period. With increasing gestational age, the rate of maternal and fetal morbidity and mortality significantly increases. Among medical methods, misoprostol is widely used to prepare the cervix in post-term pregnancies. But today, due to the high side effects of misoprostol, especially the increasing need for cesarean section, some complementary medicine methods are used to prepare the cervix. The aim of this study was to compare the effect of Misoprostol and Evening primrose oil capsule with Misoprostol on delivery method in post-term pregnancies.

 This study was performed as a single-blind randomized clinical trial on 130 pregnant women with post-term pregnancy referring to the delivery ward of Besat Hospital in Sanandaj, Iran. The samples were selected by available sampling method and assigned to the intervention and control groups by random sampling method. In the intervention group, a 500 mg capsule of evening primrose oil was given vaginally and 25 micrograms of misoprostol were given sublingually, and in the control group, an ineffective capsule was given vaginally with 25 micrograms of misoprostol sublingually. Demographic data, clinical characteristics and delivery method were used for data collection. Data were analyzed by SPSS software version 21 and statistical tests such as Chi-square, t-test and ANOVA. P-value less than 0.05 was considered significant.

 Findings showed that there was no significant difference between the two groups in terms of demographic and midwifery characteristics and the two groups were homogeneous in this respect (P>0.05). But in the evening primrose oil and misoprostol group, the mean bishop score was significantly increased compared to the misoprostol group (P<0.05). Also, in the evening primrose oil and misoprostol group (12.3%), the need for cesarean section was lower than placebo and misoprostol group (41.5%) (P<0.0001).

 The results of the study showed that the use of vaginal capsules of evening primrose oil with misoprostol compared to misoprostol alone while helping to ripening the cervix is associated with a lower rate of cesarean section.