Follicular status at the menopause.

The store of ovarian follicles which is formed before birth progressively diminishes as a result of follicle death (atresia) and recruitment towards ovulation and will become barren in time. Depletion has occurred in the human ovary at or shortly after the menopause bringing reproductive potential, which has been declining for several years, to a final halt. Several factors can affect the timing of menopause and it appears that changes in the rates of follicle death have a greater impact than differences in the initial numbers of follicles. It is argued that the precocious loss of fecundity in humans, as compared with virtually all animals, has arisen adventitiously as a consequence of the evolution of long life relative to body weight.