The menopause transition

The menopause transition is defined as the permanent cessation of menstruation resulting from the loss of ovarian follicular activity. Termination of ovarian function and menses is not an acute physiologic event; rather, the physiologic antecedents associated with the transition from premenopausal to postmenopausal follicular function occurs in the perimenopause (menopause transition). The proposed model of hormonal changes at the time of the transition has been expanded to include not only estrogen declines but also a broader range of hormones and alterations in the pattern and frequency of changes in hormone levels. The expanded menopause model also incorporates comorbid medical and psychiatric conditions and environmental influences and behaviors as covariates that influence the expression of menopause-related events. This broader view is likely to elucidate previously confusing data, as the proper understanding of potentially complex exposures, effect modifiers, and confounders is more likely to provide clearer answers to critical research questions.