Misoprostol with or without letrozole pretreatment for termination of pregnancy: a randomized controlled trial.

Objective: To compare the success rate and side effects of letrozole and misoprostol versus misoprostol alone for medical termination of early pregnancy.

Methods: Patients requesting termination of pregnancy up to 63 days of gestation were randomized into two groups. The letrozole group received letrozole 10 mg daily for 3 days followed by 800 micrograms of vaginal misoprostol, while the placebo group received placebo for 3 days followed by the same dosage of misoprostol. The complete abortion rate and the side effects profiles of the two groups were compared. The primary outcome measure was the complete abortion rate.

Results: A total of 168 women were recruited. The complete abortion rate of the letrozole group was significantly higher than that of the placebo group (86.9% compared with 72.6%, relative risk [RR] 1.20, 95% confidence interval [CI] 1.03-1.40). The complete abortion rate in gestations up to 49 days was significantly higher in the letrozole group than in the placebo group (93.3% compared with 78.7%, RR 1.19, 95% CI 1.002-1.40), while the corresponding rates for gestation between 50 and 63 days were not significantly different between the two groups. There were significantly fewer women complaining of vomiting in the letrozole group than those in the placebo group (8.3% compared with 19.0%, P=.043, RR 2.29, 95% CI 1.005-5.27).

Conclusion: The use of letrozole and misoprostol is associated with a higher complete abortion rate.

Clinical Trial Registration: HKClinicalTrials.com, http://www.hkclinicaltrials.com, HKCTR-349.

Level Of Evidence: I.