Comparison of efficacies of letrozole and clomiphene in ovulation induction

Objective:To observe the efficacies of letrozole and clomiphene in ovulation induction.Methods:800 cases with ovulation dysfunction(2 186 cycles) were divided into two groups randomly,the women in the two groups were treated with letrozole(2.5 mg,once a day for 5 days) or combined with human menopausal gonadotropin(HMG),clomiphene(50mg,once a day for 5 days) or combined with HMG;the ovulation rates,pregnancy rates and abortion rates in the two groups were observed and compared.Results:There was no significant difference in cancellation rate of menstruation cycle,the amount of follicles with mean follicle diameter(MFD)≥15 mm on the day of intramuscular injection of HCG,the incidence of ovarian hyperstimulation syndrome(OHSS) between the two groups(P0.05);the occurrence rate of dominant follicles of single letrozole group or clomiphene group: for the cases with ovulation dysfunction and without polycystic ovary syndrome(PCOS),the occurrence rate of dominant follicles in letrozole group was significantly higher than that in clomiphene group;for the cases with PCOS,the occurrence rate of dominant follicles in letrozole group was significantly lower than that in clomiphene group;for the cases with luteinizing unruptured follicle syndrome(LUFS),the occurrence rate of dominant follicles in letrozole group was significantly higher than that in clomiphene group.For the cases with small follicle ovulation,the largest MFD on the day of intramuscular injection of HCG in letrozole group was significantly lower than that in clomiphene group;the pregnancy rate in letrozole group was significantly higher than that in clomiphene group;the thickness of endometrium on the day of intramuscular injection of HCG in clomiphene group was significantly thinner than that in letrozole group;cervical Insler score on the day of intramuscular injection of HCG in clomiphene group was significantly lower than that in letrozole group;the early abortion rate in clomiphene group was significantly higher than that in letrozole group,there was significant difference in the above indexes between the two groups.Conclusion:Letrozole is inferior to clomiphene in aspects of inducing the occurrence of dominant follicles in cases without PCOS,improving follicular development of cases with small follicle ovulation,but the ovulation rate and pregnancy rate of letrozole are higher than those of clomiphene,and the early abortion rate of letrozole is lower than that of clomiphene.