Abstract: Objective：To investigate the effect of age on the clinical outcomes of in vitro fertilization-embryo transfer (IVF-ET). Methods: The clinical data of 4 512 infertile women who received IVF-ET in our Reproductive Medicine Center from January 2013 to July 2017 was analyzed retrospectively. All subjects were divided into six groups: younger than 35 years (3 619 cases, 11 patients were lost in follow-up), aged 35-37 years (479 cases), aged 38-40 years (262 cases), aged 41-42 years (90 cases), aged 43-44 years (39 cases), and older than 44 years (23 cases). The clinical pregnancy rate, first-trimester abortion rate, late abortion rate, ectopic pregnancy rate and live birth rate were compared among six groups. Results: There were decreases with age in the clinical pregnancy rate (P＜0.000 1), while the clinical pregnancy rate was best in the group of ＜35 years(54.42%). Meanwhile，the early abortion rate was increased significantly with age, especially in the women over 35 years (P＜0.01), and almost reached to 40% in the women more than 40 years. The live birth rate was decreased with age (P＜0.000 1), and this rate was 0 in those women aged more than 44 years. Conclusions: Age is a key factor related to the clinical outcomes of IVF-ET. The early intervention treatment should be advocated in those infertile women aged over 38 years because of the poor clinical outcomes.

Key words: Fertilization in vitro, Embryo transfer, Age factors, Pregnancy outcome