The menopausal transition: endocrinological and epidemiological considerations

Abstract

The human menstrual cycle is characterized by a series of dynamic hormonal relationships that result in the regular maturation of ovarian follicles, ovulation and corpus luteum formation. As methodology has changed and improved, it has become possible to examine these events in greater detail. The simple analysis of menstrual cycle length, when done with care in a large number of women over long time spans, has revealed much about the fundamental biological rhythm of the menstrual cycle. Of particular interest are the predictable changes in cycle length and variability that occur at different stages of reproductive life (Treloar et al., 1967; Vollman, 1977). Basal body temperature records add another dimension to the analyses of menstrual cycle length because they permit estimation of the length of the pre- and post-ovulatory phases of the menstrual cycle and provide some index of the integrity of corpus luteum function.