Comparing the Effects of Misoprostol/Letrozole and Misoprostol/Placebo on Medical Abortion Success Rate: A Randomized Clinical Trial

Background: Abortion is the medical or surgical termination of pregnancy before the 20th week. However, dilation and curettage have been associated with hazards such as uterine rupture, heavy bleeding, and infection. Therefore, in recent decades, pharmacological therapies have become more widely accepted. Objectives: This research compared the medical abortion success rates of misoprostol/letrozole versus misoprostol/placebo. Methods: This randomized clinical study was conducted at Mashhad University of Medical Sciences hospitals between 2018 and 2019, involving pregnant women who were candidates for medical abortion. The study population was divided into two groups based on whether they had undergone cesarean section (CS). Each group was randomly assigned to either a control or an intervention group. In the CS group, there were 52 patients in the intervention group and 52 in the control group. The control group received a regimen of misoprostol and placebo, while the intervention group received a combination of misoprostol and letrozole. Results: There was no statistically significant difference in age (31.59 ± 5.6 vs. 31.06 ± 4.6, P value = 0.605), gestational age by ultrasound (11.20 ± 3.3 vs. 10.29 ± 2.6, P value = 0.135), or blood pressure between the control and intervention groups. However, the analysis showed a statistically significant difference in the rate of complete abortion (12 (23.5%) vs. 28 (54.9%), P value = 0.001) between the two groups. In the non-CS group, there was a significant difference in age between the control and intervention groups. The study analyses also revealed a significant difference in the rate of complete abortion between the two groups (24 (46.2%) vs. 36 (72.0%), P value = 0.008). Conclusions: Letrozole is recommended in combination with misoprostol for medical abortions because it increases the likelihood of complete abortion and reduces the duration of the abortion process.