the effectiveness of using misoprostol with and without letrozole for successful medical abortion, a randomized placebo-controlled clinical trial

background: in developing countries it is important to the exploration of available and safe regimens for medical abortion. the present study was designed to assess the effect of letrozole compared to placebo pretreatment followed by sublingual misoprostol for therapeutic abortion in eligible women with gestational age less than 17 weeks. materials and methods: in this randomized control trail, 130 women eligible for legal abortions were randomly divided into two groups of case and controls. cases received daily oral dose of 10 mg letrozole 10 mg letrozole for three days followed by sublingual misoprostol. controls received daily oral dose of placebo followed by sublingual misoprostol. the dose of misoprostol was administrated according to acog guidelines based on patients’ gestational age. the rate of complete abortion, induction-of-abortion time, and side-eff ects were assessed as main outcomes. results: complete abortion was observed in 46 (76.7%) letrozole group and 26 (42.6%) controls ( p < 0.0001). also, in 14 subjects of letrozole group and 35 subjects in placebo group, the placenta was not delivered during follow-up and curettage was performed. the mean interval induction-to-abortion was 5.1 h in letrozole group and 8.9 h in control ( p < 0.0001). the cumulative rates of the induction-of-abortion time were a significant difference between the two groups ( p < 0.0001). the incidence and severity of side effects was comparable for the two groups ( p = 0.9). conclusion: letrozole could be a quite beneficial adjuvant to misoprostol for induction of complete abortion in those who are candidates for legal medical abortion.