Clinical study on the effects of different doses of letrozole on ovulation induction in infertile women with polycystic ovary syndrome

Objective To compare the effects of 2. 5 mg and 5 mg letrozole on ovulation induction.Methods Totally 121 infertile women with polycystic ovarian syndrome( PCOS) were divided into two groups. In A group,57 cases were taken 2. 5 mg letrozole once for 5-day and other 64 cases were taken 5 mg letrozole once for5-day. The follicle diameter and endometrial thickness were monitored by the transvaginal ultrasound. The women took estradiol valerate when the endometrial was thin. When the diameter of the biggest follicle reached 18 mm,10 000 IU human chorionic gonadotrophin( HCG) was injected to trigger ovulation. Results The thickness of endometrium,the ratio about A type of endometrium and the dosage of estradiol were no significant differences( P 0. 05). The numbers of dominant follicles and total ovulation follicles in B group were higher than those in A group,associated with significantly fewer days of stimulation( P 0. 05). The number of mature follicles,maximum follicle diameter( MFD),the rate of ovulation,OHSS rate and spontaneous abortion rate were no significant differences( P 0. 05). The pregnancy rate was significantly higher in B group( P 0. 05). Conclusion It appears that 5 mg is a preferable letrozole dose for ovulation induction in infertile women with PCOS.