The role of maternal age in assisted reproduction.

There is a significant decline in human fecundity with advancing age. A significant decrement in success rates is also seen in older women undergoing assisted reproduction, including in-vitro fertilization. We have observed a drop in the ongoing pregnancy rate per embryo transfer, from 48.8% in women aged < 30 years to 13.6% in women aged > or = 42 years. Embryo implantation rates also decline in a linear fashion, from 29% in women < 34 years to approximately 5% at age 42. We observed that the impaired implantation efficiency seen in older women is apparently independent of the magnitude of their stimulation response. Oocyte factors are felt to be primarily responsible; however, some available data suggest that uterine factors, e.g. diminished endometrial receptivity, may also play a role. There are presently no treatment strategies apart from oocyte donation, which have been shown to significantly improve implantation efficiency in older women. However, recent efforts have focused on the continued development of improved stimulation protocols, facilitation of embryo implantation by zona pellucida micromanipulation, and the possibility of screening preimplantation embryos for aneuploidy.