Efficacy of Letrozole in Clomiphene -resistant Infertile Women with Polycystic Ovarian Syndrome

Objective: To evaluate the clinical efficacy of letrozole in treatment of clomiphene-resistant women with polycystic ovarian syndrome(PCOS).Methods:Eighty-eight clomiphene-resistant women with PCOS were enrolled in this prospective,randomized,open-labeled study between Jan.2010 and Jan.2011.All subjects were divided into three groups andomly:the Letrozole group received Letrozole(LE)2.5 mg/d per os for 5 days during days 3-7 of menstrual circle,the control group was administered HMG progressive increasing from 75 IU/d intramuscular.for ovulation induction on day 5 of menstrual circle;the LE+HMG group was treated with LE 2.5 mg/d for 5 days during days 3-7 of menstrual circle,from day 8,then treated with HMG 75 IU/d intramuscular.The transvaginal ultrasonography was applied to observe follicle growth and ovulation.When the follicular diameter was ≥18 mm in length,hCG(5000 IU) was injected to induce ovalution.Ovulation rate,pregnancy rate and the endometrial thickness were observed.Results:Ovulation rate and pregnacy rate were similar in three groups.The incidences of single dominant follicle in LE group and LE +HMG group were significantly higher than that in HMG group(P0.05),while the numbers of mature follicles in the LE group and LE+HMG group were lower than that in the HMG group.There was insignificant difference in endometrial thickness at the day of hCG injection among three groups.Conclusions:Letrozole can get good ovulation rate and pregnancy rate in those clomiphene-resistant women with PCOS.Compared with HMG alone,LE combined with HMG on the controlled ovarian stimulation can get higher ovulation rate with the lowered dose of HMG.