RESUMEN
Objective To analyze the effects of down-regulation+hormone replacement therapy(HRT)endometrial preparation regimen on the pregnancy outcomes of advanced age women(≥35 years old)undergoing frozen-thawed embryo transfer.Methods The clinical data of 329 patients with frozen-thawed em-bryo transfer in this hospital from June 2020 to June 2022 were analyzed retrospectively.Among them,149 pa-tients receiving gonadotropin-releasing hormone analogue(GnRHa)down-regulation+HRT endometrial preparation were included in the group A,and the other 180 patients with HRT endometrial preparation were included in the group B.The basic situation,endometrial transformation day situation and clinical outcome were compared between the two groups.The group A and group B were further divided into the two sub-groups according to age:group A1(35-＜40 years old,n=101),group A2(≥40 years old,n=48),group B1(35-＜40 years old,n=99)and group B2(≥40 years old,n=81).The effects of two endometrial prepara-tion regimens were compared among the different age groups.Results There were no significant differences in the age,infertility years,BMI,anti-Mullerian hormone level,as well as basal hormones levels such as estra-diol,progesterone,follicle-stimulating hormone,luteinizing hormone(LH),prolactin and testosterone between the two groups(P＞0.05).The levels of estradiol and LH on the endometrial transformation day in the group A were significantly lower than those in the group B(P＜0.05),the endometrial thickness,proportion of the patients with endometrial thickness ≥8 mm and proportion of the patients with type Ⅲ blood intima in the group A were significantly higher than those in the group B(P＜0.05).There was no significant difference in the number of transplanted embryos and the number of transplanted excellent embryos between the two groups(P＞0.05).The clinical pregnancy rate and embryo implantation rate in the group A were significantly higher than those in the group B(46.31％vs.35.56％;33.33％vs.25.18％,P＜0.05),and there was no significant difference in the early miscarriage rate between the two groups(P＞0.05).The further subgroup analysis showed that the clinical pregnancy rate and embryoimplantation rate in the group A2 were significant-ly higher than those in the group B2(35.42％vs.18.52％;21.43％vs.12.40％,P＜0.05),while there was no significant difference between the group A1 and group B1(P＞0.05).Conclusion The advanced age pa-tients undergoing frozen-thawed embryo transfer could select GnRHa down-regulation+HRT regimen to a-chieve better pregnancy outcomes,especially for those age ≥40 years old.