The response to ovarian hyperstimulation and in-vitro fertilization in women older than 35 years.

There are conflicting reports concerning the effect of female age and potential reproductive function. We assessed the response to ovarian hyperstimulation in two consecutive IVF cycles in 25 women greater than 35 years of age and compared their response to a control group of 48 women less than 35 years of age who conceived in our IVF programme. In the older women, the maximal oestradiol response was proportional to the number of vials of HMG used and did not differ from the response of the younger women. Similarly, the number of follicles of diameter greater than 1.0 cm, the number of oocytes recovered and the number of embryos which cleaved did not differ between the older and the younger women. However, conception rates were markedly lower in the older women than the overall pregnancy rate in the IVF programme during the same time period. We conclude that the older women in this study have a normal response to ovarian stimulation but may have a decreased receptivity of the endometrium or increased numbers of embryos with chromosomal abnormalities, leading to a reduced rate of implantation.