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PerimenopauseArticle

What Happens During Menopause?

The stages, timing and body changes of the menopausal transition, with the research behind each point.

October 22, 20268 min read

Short answer

Menopause is the point when periods stop for good, confirmed after 12 months without one. It happens as the ovaries' supply of follicles runs low and hormone levels change. In the United States, women reach it at about 51 to 52 on average. The years before it, the menopausal transition, often bring irregular periods, hot flashes and changes in sleep, and usually last several years. Bone loss speeds up and LDL cholesterol rises around the final period, which makes these years a good time to plan ahead.

A young science

Much of what is known about the menopausal transition is recent. Researchers agreed the first formal staging system in 2001 and revised it in 2012.[1][2] The Study of Women's Health Across the Nation (SWAN), which supplies many of the numbers on this page, began following women through midlife in 1996.[3] The science is still young, and some important questions remain open.

Why it happens

The ovaries hold a reserve of follicles that is used up over life. As the reserve runs low, markers of it such as AMH and antral follicle count fall, and the hormone FSH rises and varies from cycle to cycle.[2] Mathematical models of this depletion reproduce the spread of ages at which women reach menopause across a population.[4] Cycles first change in length, then periods become further apart, and finally they stop.[2]

The stages

The STRAW+10 system divides this process into stages around the final menstrual period: the late reproductive years, the early and late menopausal transition, and early and late postmenopause. "Perimenopause" runs from the start of the early transition to 12 months after the final period.[2] See the stages in detail.

When it happens

  • In large US cohorts, the median age at the final menstrual period is about 51.3 to 52.5.[5][6] Across studies on six continents, the average is about 48.8.[7]
  • About 12% of women worldwide reach menopause early, between 40 and 45.[8] About 3.5% experience premature ovarian insufficiency, before 40.[9]
  • Smoking is linked to menopause about 1 year earlier on average.[7]

Read more about timing.

How long the transition lasts

The late transition lasts 1 to 3 years on average.[2] Measured from its very beginning, the whole transition is longer: in SWAN, its median length ranged from about 4.4 years for women who started it latest to about 8.6 years for women who started it earliest.[10]

Common changes during the transition

  • Periods. Cycle length becomes irregular. Long or heavy bleeding episodes are common: in SWAN, 77.7% of women had three or more episodes of bleeding lasting 10 days or more.[11]
  • Hot flashes and night sweats. In SWAN, frequent symptoms (on 6 or more days in two weeks) lasted a median of 7.4 years in total and continued a median of 4.5 years after the final period.[12] A meta-analysis using a broader definition estimated a median of about 4 years, with about 10% of women still reporting symptoms 12 years after the final period.[13]
  • Sleep. In a survey of more than 12,000 midlife women, 38% reported difficulty sleeping. Rates were highest in the late transition (45.4%) and after surgical menopause (47.6%).[14]
  • Mood. Clinical guidelines describe perimenopause as a window of vulnerability for depression. Most women who have major depression during perimenopause have had an earlier episode.[15]
  • Memory and concentration. In SWAN, women in late perimenopause did not show the usual improvement on repeated cognitive tests. The improvement returned after menopause, which suggests the difficulties may be temporary.[16]

Changes around and after menopause

  • Bone. Bone density loss begins about 1 year before the final period and slows, but does not stop, about 2 years after it. Over 10 years, women in SWAN lost 10.6% of lumbar spine bone density.[17]
  • Heart and blood vessels. Total cholesterol, LDL cholesterol and apolipoprotein B rise sharply within the year around the final period.[18] The American Heart Association calls the transition a time of accelerating cardiovascular risk, and a time to start prevention early.[19]
  • Body composition. At the start of the transition, the rate of fat gain doubles and lean mass begins to decline, even though the rate of weight gain does not change.[20]
  • Genitourinary health. Vaginal dryness, discomfort and urinary symptoms, together called the genitourinary syndrome of menopause, affect an estimated 27% to 84% of postmenopausal women and are likely underdiagnosed and undertreated.[21]

Treatment options

Many treatments exist, and the right choice depends on each woman's health and preferences. The North American Menopause Society (now The Menopause Society) states that hormone therapy is the most effective treatment for hot flashes and for genitourinary symptoms. For women under 60, or within 10 years of menopause, who have no contraindications, it finds the benefit-risk balance favorable for treating bothersome hot flashes and preventing bone loss.[22] For genitourinary symptoms, non-hormone therapies give enough relief for most women whose symptoms are mild.[21] A clinician can help weigh these options.

What researchers are still working out

  • Why the timing and length of the transition vary so much from one woman to the next. Age at onset explains part of it, and SWAN investigators call for better markers of when the transition begins.[10]
  • How to anticipate the timing for one woman, years ahead. What AMH can tell you.
  • Which midlife changes come from menopause itself and which come from aging. Some heart-disease risk factors track the final period closely, while others follow age.[18]

LifeAhead works on the second question: forecasting the approximate timing of the menopausal transition, with a prediction interval, for clinicians to use in counseling. Read about the science.

Planning ahead

Because bone loss and changes in cholesterol begin around the final period, the years before it are a natural time to talk with a clinician about bone and heart health.[17][19] Keeping track of cycle length helps too, since changes in the cycle mark the start of the transition.[2] See the planning timeline.

References

  1. Soules MR, Sherman S, Parrott E, et al. Executive summary: Stages of Reproductive Aging Workshop (STRAW). Fertil Steril. 2001;76(5):874-878. doi:10.1016/s0015-0282(01)02909-0
  2. Harlow SD, Gass M, Hall JE, et al. Executive summary of the Stages of Reproductive Aging Workshop + 10: addressing the unfinished agenda of staging reproductive aging. J Clin Endocrinol Metab. 2012;97(4):1159-1168. doi:10.1210/jc.2011-3362
  3. El Khoudary SR, Greendale G, Crawford SL, et al. The menopause transition and women's health at midlife: a progress report from the Study of Women's Health Across the Nation (SWAN). Menopause. 2019;26(10):1213-1227. doi:10.1097/GME.0000000000001424
  4. Johnson J, Emerson JW, Lawley SD. Recapitulating human ovarian aging using random walks. PeerJ. 2022;10:e13941. doi:10.7717/peerj.13941
  5. McKinlay SM, Brambilla DJ, Posner JG. The normal menopause transition. Maturitas. 1992;14(2):103-115. doi:10.1016/0378-5122(92)90003-M
  6. Gold EB, Crawford SL, Avis NE, et al. Factors related to age at natural menopause: longitudinal analyses from SWAN. Am J Epidemiol. 2013;178(1):70-83. doi:10.1093/aje/kws421
  7. Schoenaker DA, Jackson CA, Rowlands JV, Mishra GD. Socioeconomic position, lifestyle factors and age at natural menopause: a systematic review and meta-analyses of studies across six continents. Int J Epidemiol. 2014;43(5):1542-1562. doi:10.1093/ije/dyu094
  8. Golezar S, Ramezani Tehrani F, Khazaei S, et al. The global prevalence of primary ovarian insufficiency and early menopause: a meta-analysis. Climacteric. 2019;22(4):403-411. doi:10.1080/13697137.2019.1574738
  9. Panay N, Anderson RA, Bennie A, et al. Evidence-based guideline: premature ovarian insufficiency. Hum Reprod Open. 2024;2024(4):hoae065. doi:10.1093/hropen/hoae065
  10. Paramsothy P, Harlow SD, Nan B, et al. Duration of the menopausal transition is longer in women with young age at onset: the multiethnic Study of Women's Health Across the Nation. Menopause. 2017;24(2):142-149. doi:10.1097/GME.0000000000000736
  11. Paramsothy P, Harlow SD, Greendale GA, et al. Bleeding patterns during the menopausal transition in the multi-ethnic Study of Women's Health Across the Nation (SWAN): a prospective cohort study. BJOG. 2014;121(12):1564-1573. doi:10.1111/1471-0528.12768
  12. Avis NE, Crawford SL, Greendale G, et al. Duration of menopausal vasomotor symptoms over the menopause transition. JAMA Intern Med. 2015;175(4):531-539. doi:10.1001/jamainternmed.2014.8063
  13. Politi MC, Schleinitz MD, Col NF. Revisiting the duration of vasomotor symptoms of menopause: a meta-analysis. J Gen Intern Med. 2008;23(9):1507-1513. doi:10.1007/s11606-008-0655-4
  14. Kravitz HM, Ganz PA, Bromberger J, et al. Sleep difficulty in women at midlife: a community survey of sleep and the menopausal transition. Menopause. 2003;10(1):19-28. doi:10.1097/00042192-200310010-00005
  15. Maki PM, Kornstein SG, Joffe H, et al. Guidelines for the evaluation and treatment of perimenopausal depression: summary and recommendations. Menopause. 2018;25(10):1069-1085. doi:10.1097/GME.0000000000001174
  16. Greendale GA, Huang MH, Wight RG, et al. Effects of the menopause transition and hormone use on cognitive performance in midlife women. Neurology. 2009;72(21):1850-1857. doi:10.1212/WNL.0b013e3181a71193
  17. Greendale GA, Sowers M, Han W, et al. Bone mineral density loss in relation to the final menstrual period in a multiethnic cohort: results from the Study of Women's Health Across the Nation (SWAN). J Bone Miner Res. 2012;27(1):111-118. doi:10.1002/jbmr.534
  18. Matthews KA, Crawford SL, Chae CU, et al. Are changes in cardiovascular disease risk factors in midlife women due to chronological aging or to the menopausal transition? J Am Coll Cardiol. 2009;54(25):2366-2373. doi:10.1016/j.jacc.2009.10.009
  19. El Khoudary SR, Aggarwal B, Beckie TM, et al. Menopause transition and cardiovascular disease risk: implications for timing of early prevention: a scientific statement from the American Heart Association. Circulation. 2020;142(25):e506-e532. doi:10.1161/CIR.0000000000000912
  20. Greendale GA, Sternfeld B, Huang M, et al. Changes in body composition and weight during the menopause transition. JCI Insight. 2019;4(5):e124865. doi:10.1172/jci.insight.124865
  21. The North American Menopause Society. The 2020 genitourinary syndrome of menopause position statement of The North American Menopause Society. Menopause. 2020;27(9):976-992. doi:10.1097/GME.0000000000001609
  22. The North American Menopause Society. The 2022 hormone therapy position statement of The North American Menopause Society. Menopause. 2022;29(7):767-794. doi:10.1097/GME.0000000000002028

This article is for general education and does not replace advice from your healthcare provider.

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