Effect of Letrozole on Clomiphene-Resistant Polycystic Ovary Syndrome

Objective To explore the effect of letrozole induction of ovulation on clomiphene-resistant polycystic ovary syndrome(PCOS). Methods Seventy-six patients with clomiphene-resistant PCOS were divided into three groups. Group A was orally given letrozole(5 mg/day) from the 4th to the 8th day of menstrual cycle; Group B was orally given letrozole(2.5 mg/day) from the 4th to the 8th day of menstrual cycle, followed by intramuscular injection of hCG(75 U/day)from the 9th day of menstrual cycle; Group C was orally given menotrophin(75 U/day) from the 5th day of menstrual cycle. The number of dominant follicles, endometrial thickness, E2 level, ovulation rate, pregnancy rate and abortion rate were compared among the three groups. Results There were no obvious differences between group A and group B in the number of dominant follicles, endometrial thickness and E2 level(P 0.05).Compared with group C, the number of dominant follicles and the level of E2 were significantly different from those in group A and group B(P 0.05). The ovulation rate and pregnancy rate were, respectively, 85.2% and 48.1% in group A, 88% and 48% in group B, and 58.3% and 33.3% in group C. Compared with group C, both ovulation rate and pregnancy rate significantly increased in group A and group B(P0.05). However, no significant differences were found between the two groups(P0.05). Conclusion Letrozole alone or in combination with menotrophin can promote ovulation and elevate pregnancy rate in patients with clomiphene-resistant PCOS. However, menotrophin alone results in the development of too many dominant follicles, and therefore leads to a high abandonment rate and a low pregnancy rate.