Influence of decreasing the number of embryos transferred on pregnancy outcomes in advanced age women undergoing in vitro fertilization-embryo transfer

Abstract

Objective To study the effect of decreasing the number of embryos transferred on pregnancy outcomes in women aged ≥35 years. Methods A retrospective study was performed in infertile women aged≥35 years undergoing fresh transfer cycles, who were treated in our center between January 2009 and December 2015. After egg retrieval on day 3, the patients with more than 3 embryos who were transferred 2 embryos were defined as study group, which contained 2 361 cycles. Each IVF cycles were matched to the control cycles by age, body mass index (BMI) and basal follicle stimulating hormone (FSH) level. Control group which were transferred 3 embryos had a total of 2 361 cycles. The clinical outcomes in the two groups were analyzed and compared. The study and control groups were divided into three age groups, respectively, namely 35-37 years group, 38-40 years group, and >40 years group. The effect of decreasing the number of embryo transferred on pregnancy outcomes were compared between different age groups. Results There were no significantly differences in terms of patients age, duration of infertility, BMI, basal FSH level, total gonadotrophin (Gn) used dosage and Gn stimulation days (P>0.05). Between study group and control group, there were no major difference in the prevalence of clinical pregnancy rate, abortion rate and live birth rate (P>0.05). The incidence of implantation rate (13.55%) in study group was significantly higher than that in control group (10.36%, P 40 years, there were no significantly differences in clinical pregnancy rate, abortion rate and live birth rate between study group and control group (P>0.05). The prevalence of multiple pregnancy rate (6.41%) in study group was evidently lower than control group (18.18%, P=0.035). Conclusion For women≥35 years old reducing the number of embryos transferred does not effect clinical pregnancy rate and live birth rate, but can reduce the occurrence of multiple pregnancy rate and improve the clinical outcome of the patients. Key words: In vitro fertilization and embryo transfer (IVF-ET); Advanced age; Clinical pregnancy rate; Multiple pregnancy rate; Live birth rate