OBJECTIVE: To investigate the effects of letrozole（ LE） on ovulation induction

visfatin

and monocyte chemoattractant protein-1（ MCP-1） in patients with polycystic ovary syndrome（ PCOS）. METHODS: A total of 100 patients with PCOS admitted into Central Hospital of Enshi Tujia and Miao Autonomous Prefecture from Jan.2018 to Jun. 2019 were extracted to be divided into the IE group and the clomiphene citrate（ CC） group according to the random number table

with 50 cases in each group. The IE group was given oral administration of letrozole tablets on the 3 rd to 7 th d of menstrual cycle

and the CC group received oral administration of clomiphene citrate capsules.The ovulation induction effects

endometrial thickness in different time points

levels of serum visfatin

MCP-1

testosterone（ T）

luteinizing hormone（ LH）/follicle stimulating hormone（ FSH）

insulin resistance index（ HOMAIR） and body mass index（ BMI） before and after treatment were observed between two groups

and the occurrence of adverse drug reactions was recorded. RESULTS: The number of mature follicles

incidence of ovarian hyperstimulation syndrome（ OHSS） and early abortion rate in the LE group were significantly lower than those in the CC group

and the incidence of single follicle was significantly higher than that in the CC group

with statistically significant difference（ P<0. 05）. The endometrial thickness in follicular phase and luteal phase in the LE group was significantly greater than that in the CC group

with statistically significant difference（ P<0. 05）. After treatment

the serum visfatin in the LE group was significantly higher than that in the CC group

while the levels of MCP-1

T

LH/FSH

HOMA-IR and BMI were significantly lower than those in the CC group

with statistically significant differences（ P < 0. 05）. The incidences of adverse drug reactions in the CC group and the LE group were 6. 00%（ 3/50） and 4. 00%（ 2/50）

respectively

and the difference was not statistically significant（ P > 0. 05）. CONCLUSIONS: LE can promote the increase of visfatin and inhibit the secretion of MCP-1 in patients with PCOS. It is an effective and safe ovulation-promoting drug with high incidence of single follicles

which can avoid the multiple pregnancy and OHSS and improve the endometrial receptivity.