Abstract: Objective：To observe the influence of advanced female age on the outcome of in vitro fertilization and embryo transfer（IVF-ET）. Methods：Total of 753 IVF-ET cycles of women with age ≥35 years old from July 2001 to July 2009 were analyzed. According to female age，the patients were divided into 4 groups：group A（35-36 years），group B（37-38 years），group C（39-40 years），group D（≥41 years）. Results：The live birth rate of 724 cycles with embryos transferred was 13.3%. With the increasing of age，the number of oocytes retrieved，the implantation rate and the live birth rate significantly decreased（P values were 0.001，0.001 and 0.006，respectively）. The number of oocytes retrieved were 9.8±6.0，8.6±5.4，6.7±4.3 and 5.3±4.4，respectively. The implantation rates were 17.9%，12.8%，10.0% and 4.3%，respectively. The live birth rates were 16.7%，13.3%，12.4% and 2.3%，respectively. No live birth was obtained by 45 women aged ≥43 years. Conclusions：With the age increases，the implantation rate and live birth rate of IVF-ET decrease significantly which is more obvious when the age older than 40 years. Advanced researches are needed to determine the upper limit of age for IVF.

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