Effect of Letrozole on ovulation induction in women with polycystic ovary syndrome

Objective:To evaluate and compare the effect of treatment with Letrozole vs. hMG on the hormonal and biochemical features of patients with polycystic ovarian syndrome (PCOS).Methods:Forty-one Chinese women with PCOS participated in this prospective,randomized,open-labeled study between January 1th 2006 and January 31th 2007. All subjects were divided into two groups randomly:the experimental group received Letrozole (LE)2.5 mg/d for 5 days during days 3~7 of menstrual circle,the control group was given hMG progressive increasing from 37.5 mg/d for ovulation induction therapy on the 5th day of menstrual circle. The transvaginal sonography was applied to observe growth of follicle and ovulation. Then when the follicular diameter was ≥18 mm in length injected hCG 10 000 IU inducing ovalution. Luteinizing hormone (LH), estradiol (E2), testosterone (T) levels were estimated with the blood of elbow vein at the day of HCG injection. Ovulation rate, pregnancy rate, the endometrial thickness and reproductive hormones were observed.Results:Ovulation rate and pregnacy rate were similar in experimental group and control group. The morbidity of single dominant follicle was obviously higher in experimenta group than that in control group (P0.05),while the number of mature follicle produced a significant reduction in experimenta group. There was no significant reduction after either group for endometrial thickness, E2 and T levels in serum at the day of HCG injection.Conclusion:Letrozole produces a similar ovulation rate and pregnancy rate with hMG. And the morbidity of single dominant follicle is significantly higher in experimenta group than in control group. Therefore,Letrozole may be proved to be effective in the treatment of PCOS.