Stages of Ovarian Age Defined

There are numerous metabolic and physiologic changes the occur as women age, and many of these processes are directly impacted by fluctuating and absolute estrogen and sex hormone levels.

These estrogen and sex hormone levels are impacted by ovarian function, which naturally decline as a woman ages.

A woman’s chronologic age does not necessarily correlate with her reproductive age.

There are somatic aging issues women will encounter which are influenced by chronologic age. However there are large biologic, metabolic and physiologic changes that occur intimately related to fluctuating and ultimately declining estrogen and sex hormone production from the ovaries, so called reproductive aging.

In order to standardize these changes for research and treatment purposes, stages of a woman’s reproductive (or ovarian) age have been defined by the Stages of Reproductive Aging Workshop (STRAW).

Epidemiologic and clinical studies have documented that the process of reproductive aging, although influenced by demographic factors, lifestyle, and BMI, follows a robust and predictable pattern.

STRAW made a substantial contribution to women's health research by providing consistent classification of menopause status for studies of midlife women.

Importantly, STRAW facilitated research that aimed to distinguish the health effects of ovarian versus somatic aging.

The STRAW staging system also serves as a clinical tool for women and their healthcare providers to guide the assessment of fertility, contraceptive needs, and healthcare decision making.

The STRAW staging system is widely considered the gold standard for characterizing reproductive aging through menopause.

Application of the STRAW staging system should improve comparability of studies of midlife women and facilitate clinical decision making.

STRAW Staging System

Reproductive Phase

  • -5 Stage Early

  • -4 Stage Peak

  • -3 Stage Late

    • Characterized by regular menstrual cycles and increasing levels of FSH.

    • The late reproductive stage marks the time when reproductive potential begins to decline and during which a woman may begin to notice changes in her menstrual cycles.

    • Critical endocrine parameters begin to change before overt changes in menstrual cyclicity, thus two additional substages created.

      • –3b Stage menstrual cycles remain regular without change in length or early follicular phase FSH levels; however, AMH and antral follicle counts are low.

      • –3a Stage subtle changes in menstrual cycle characteristics, specifically shorter cycles begin. Early follicular phase (cycle days 2–5) FSH increases and becomes more variable.

Menopausal Transition

  • -2 Stage Early Menopausal Transition

    • Characterized by variability in menstrual cycle length and increased levels of FSH.

    • Marked by increased variability in menstrual cycle length, defined as a persistent difference of 7 days or more in the length of consecutive cycles.

    • Persistence is defined as recurrence within 10 cycles of the first variable length cycle.

    • Cycles in the early menopausal transition are also characterized by elevated but variable early follicular phase FSH levels and low AMH levels and AFC.

  • -1 Stage Late Menopausal Transition

    • Characterized by onset of skipped cycles or amenorrhea of at least 60 days and continued elevation of FSH.

    • Marked by the occurrence of amenorrhea of 60 days or longer.

    • Menstrual cycles in the late menopausal transition are characterized by increased variability in cycle length, extreme fluctuations in hormonal levels, and increased prevalence of anovulation.

    • In this stage, FSH levels are sometimes elevated into the menopausal range and sometimes within the range characteristic of the earlier reproductive years, particularly in association with high estradiol levels.

    • Levels of FSH greater than 25 IU/L in a random blood draw characteristic of being in late transition.

    • This stage is estimated to last, on average, 1 to 3 years.

    • Symptoms, most notably vasomotor symptoms, are likely to occur during this stage.

Postmenopause

  • +1 Stage Early

    • Early postmenopause

    • Stage +1a, +1b, +1c

    • FSH continues to increase and that estradiol continues to decrease until approximately 2 years after the FMP (final menstrual period).

  • Stages +1a and +1b each last 1 year and end at the time point at which FSH and estradiol levels stabilize.

    • Stage +1a marks the end of the 12-month period of amenorrhea required to define that the FMP has occurred. It corresponds to the end of “perimenopause,” a term still in common usage that means the time around menopause and begins at Stage –2 and ends 12months after the FMP.

    • Stage +1b includes the remainder of the period of rapid changes in mean FSH and estradiol levels.

      • Based on studies of hormonal changes, Stages +1a and +1b together are estimated to last, on average, 2 years.

      • Symptoms, most notably vasomotor symptoms, are most likely to occur during this stage.

    • Stage +1c represents the period of stabilization of high FSH levels and low estradiol values

      • It is estimated to last 3 to 6 years; therefore, the entire early postmenopause lasts approximately 5 to 8 years..

  • +2 Stage Late postmenopause

    • Represents the period in which further changes in reproductive endocrine function are more limited and processes of somatic aging become of paramount concern.

    • Symptoms of vaginal dryness and urogenital atrophy become increasingly prevalent at this time.

    • However, many years after menopause, it has been observed that there may be a further decline in levels of FSH in very old persons.

Executive summary of the Stages of Reproductive Aging Workshop + 10: addressing the unfinished agenda of staging reproductive aging.. Siobán D. Harlow, PhD1, Margery Gass, MD, NCMP2, Janet E. Hall, MD3, Roger Lobo, MD4, Pauline Maki, PhD5, Robert W. Rebar, MD6, Sherry Sherman, PhD7, Patrick M. Sluss, PhD8,and Tobie J. de Villiers, MBChB, FRCOG, FCOG (SA)9 For the STRAW + 10 Collaborative Group Menopause. 2012 April ; 19(4): 387–395. doi:10.1097/gme.0b013e31824d8f40.