Comparison of the effect of vaginal misoprostol and evening primrose oil capsule with misoprostol alone on the consequences of abortion in women with intrauterine fetal death: a randomized clinical trial

BACKGROUND: Misoprostol is the choice drug for inducing an abortion with intrauterine fetal death, but it has several side effects that increase with accumulating the dose received. Induction abortion with cheap and non-invasive methods with minimal complications is essential. This study aimed to compare the effect vaginal misoprostol plus vaginal evening primrose oil capsule with vaginal misoprostol alone on the consequences of abortion in pregnant women with intrauterine fetal death at 12–20 weeks of pregnancy. METHODS: This study is a randomized, triple-blind clinical trial with two parallel groups at a ratio of 1:1. We randomized 82 women with indications of termination of pregnancy due to intrauterine fetal death into two groups. The experimental group (n = 42) received 200 mcg of misoprostol tablet with 1000 mg evening primrose oil capsule intravaginal. The control group (n = 40) received 200 mcg of misoprostol tablet with 1000 mg evening primrose oil placebo capsule intravaginal. Both groups received the drugs every 4 h for up to five doses. The primary outcome was the mean induction-to-fetal expulsion interval. Secondary outcomes were the mean dose of misoprostol, the highest pain intensity in the induction-to-fetal expulsion interval, the frequency of participants requiring blood transfusion, curettage, and the frequency of side effects of misoprostol or evening primrose oil. Pain intensity was measured through the Visual Analog Scale. RESULTS: The mean age of the experimental group was 32.30 ± 6.19 years, and the control group was 30.27 ± 7.68 years. The mean gestational age of the experimental group was 15.29 ± 2.26 weeks, and the control group was 15.10 ± 1.89 weeks. The mean induction-to-fetal expulsion interval in the experimental group (3.12 ± 2.17 h) was significantly lower than that in the control group (8.40 ± 4.1 h) (p < 0.001). The mean dose of misoprostol received in the experimental group (271.42 ± 115.39 mcg) was significantly lower than that in the control group (520 ± 201.53 mcg) (p < 0.001). Also, the mean pain intensity in the experimental group (5.02 ± 0.60) was significantly lower than that in the control group (8.65 ± 1.001) (p < 0.001). The two groups were not significantly different in the frequency of blood transfusion requirements, analgesia and drug side effects. The need for curettage in the experimental group (4.8%) was significantly lower than that in the control group (47.5%) (p < 0.001). CONCLUSIONS: Vaginal administration of evening primrose oil with misoprostol reduced duration of time of fetal expulsion, pain intensity, mean dose of misoprostol received, and the need for curettage in participants. Therefore, we suggest this method for induced abortion in women with intrauterine fetal death. TRIAL REGISTRATION: IRCT20181207041873N3. Dated 16/2/2021 prospectively registered https://en.irct.ir/user/trial/53681/view.