The menopausal transition is a progressive endocrinologic continuum that takes reproductive-aged women from regular, cyclic menses to a final menstrual period and ovarian senescence. With medical advancements, average life expectancy has increased, and most women can now expect to live at least one third of their lives in the menopause. Specifically, by 2020, approximately 43 million women will be aged 45 to 64 years (U.S. Census Bureau, 2014). Importantly, menopausal transition and the years of life spent in the postmenopausal state bring with them issues related to both quality of life and disease prevention and management (Lund, 2008).
Menopause refers to a point in time that follows 1 year after the complete cessation of menstruation, and the postmenopause describes years following that point. The average age of women experiencing their final menstrual period (FMP) is 51.5 years, but a halt to menses from ovarian failure may occur at any age. Cessation before age 40, termed premature ovarian failure, is associated with an elevated follicle-stimulating hormone (FSH) level and variable causes described in Chapter 16. Of other definitions, the older words perimenopause and climacteric generally refer to the late reproductive years, usually late 40s to early 50s. These can be used with patients but less so in scientific settings. Here, the term menopausal transition (MT) is preferred (Harlow, 2012; Soules, 2001). Characteristically, MT begins with menstrual cycle irregularity and extends to 1 year after permanent cessation of menses. This reproductive aging with loss of follicular activity progresses within a wide age range (42 to 58 years). The average age at its onset is 47, and MT typically spans 4 to 7 years (Burger, 2008; McKinlay, 1992).
As chronological age is an unreliable indicator, guidelines for classifying reproductive aging have been proposed. The first classification of stages and nomenclature for female reproductive aging were developed in 2001 and updated in 2012 at the Stages of Reproductive Aging workshop (STRAW) (Harlow, 2012). These staging criteria are guides rather than strictly applied diagnoses. Every stage may not manifest in all women, or a stage may occur out of the expected sequence. Also, the age range and duration of each stage varies for given individuals.
In the STRAW system, the anchor stage is the FMP (Fig. 21-1). Five stages precede and two stages follow the FMP. Stage –5 refers to the early reproductive period, stage –4 to the reproductive peak, and stage –3 to the late reproductive period. Stage –2 is the early MT, and stage –1 is the late MT. Stage +1a is the first year after FMP, stage +1b reflects years 2 to 5 postmenopause, and stage +2 refers to the ensuing later postmenopausal years.
The stages of reproductive aging. (Reproduced with permission from Soules MR, Sherman S, Parrott E, et al: Executive summary: ...