Aging of the Female Reproductive System

This chapter reviews the changes that occur in the female reproductive system with age. Although there is considerable variation in the exact age of menopause, the majority of women go through menopause at approximately 51 years of age, and the timing of this change has remained essentially the same since medical records have been maintained. Menopause occurs around the time that the ovarian follicular reserve becomes exhausted, and, in fact, marked variation in the follicular reserve correlates with variation in deterioration of regular menstrual cyclicity. In women, exhaustion of ovarian follicular reserve is the major factor that underlies the timing of perimenopause and menopause. Thus, ultimately, the permanent cessation of menstrual cyclicity can be largely attributed to changes within the ovaries. It appears that females are born with an enormous, but finite, postmitotic, nonrenewable endowment of follicles. At later stages of the perimenopausal transition and postmenopausal period, multiple ovarian and pituitary hormones exhibit changes in both concentrations and patterns of secretion. The highly erratic concentrations, patterns, and relationships among the hormones raise the real possibility that all aspects of the reproductive axis are no longer coordinated in the normal feedforward and feedback manner.