RESOURCES · KISO

153,800 Danish women have described what menopause is like.
That is KiSO.

Women in Healthy Transition (KiSO) is a research project at the University of Copenhagen. In the summer of 2024 every woman aged 45 to 59 living in Denmark, 575,863 in all, received a questionnaire in her digital mailbox. 153,800 answered, 27 percent. No other study of menopause has that volume, in Denmark or internationally.

The results were published in October 2025. They show that for most women menopause is a significant health challenge, not a minor inconvenience.

WHAT THE NUMBERS SHOW

Almost everyone feels it.
Many feel it a lot.

97%
experience symptoms during menopause. Only 3 percent have no symptoms at all.
83%
have at least one symptom at a moderate to very severe level.
28%
have six or more symptoms at a moderate to very severe level.
The phases of menopause

Four phases that flow into each other

Estrogen falls in waves, and symptoms do not follow the same curve. They peak only after the last period.

EstrogenSymptomsILLUSTRATION, NOT MEASURED VALUES1PERIMENOPAUSEapprox. 40-522MENOPAUSE~523EARLY POST.+1-8 years4LATE POST.+8 yearsBEFORELEVEL41 % are in perimenopause at 45Peaks 1-2 years after the last period21 % still have severe symptoms40455260Cycle and bleeding canbecome irregularLast period(12 months without bleeding)AGE
  1. 1PerimenopauseApprox. 40-52

    Estrogen swings up and down, and the cycle becomes irregular. 41 % are already in perimenopause at 45, and 54 % have moderate to very severe symptoms while they still menstruate.

  2. 2MenopauseOn average at 52

    The last period. It can only be confirmed once 12 months have passed without bleeding.

  3. 3Early postmenopause1-8 years after

    Estrogen stays low. Symptoms grow in number and strength up to the peak, typically 1 to 2 years after the last period.

  4. 4Late postmenopauseMore than 8 years after

    For most women symptoms ease. But 21 % still have severe to very severe symptoms more than eight years later.

From about 40The whole course

Four phases that flow into each other. Follow estrogen and symptoms phase by phase.

Figures from KiSO, University of Copenhagen (2025). The curves are an illustration.

THE PHASES

It starts earlier,
and lasts longer, than many think.

41% at 45
already report being in perimenopause, although the average age at the last period is 52.
54% in perimenopause
have moderate to very severe symptoms while they are still menstruating.
1 to 2 years after
the last period, symptoms peak. They grow in number and intensity along the way.
21% after 8 years
still have severe to very severe symptoms more than eight years after the last period.
THE MOST COMMON SYMPTOMS

Sleep is hit most often.
Share with moderate to very severe symptoms.

  • Sleep problems54 %
  • Hot flushes43 %
  • Physical and mental exhaustion39 %
  • Joint and muscle pain39 %
  • Sexual problems35 %
ABOUT THE PROJECT

Three strands, fifteen years.

The survey

KiSO Survey goes to every woman aged 45 to 59 in Denmark and is repeated every three years for 15 years, so the course can be followed over time.

The cohort

KiSO Cohort follows 200 women through the whole of menopause, physiologically, socially and personally.

The qualitative studies

Interviews about working life and private life, about how symptoms affect self-image and agency, and about the meeting with the GP.

KiSO is based at the Department of Public Health and the Department of Nutrition, Exercise and Sports at the University of Copenhagen. The survey is led by associate professor Maria Hybholt with PhD student Sigrid Normann Biener and associate professor Terese Sara Høj Jørgensen.

KISO AND RYMA

Ryma builds on what KiSO has shown.
But Ryma is not part of KiSO.

Ryma's knowledge of menopause builds on KiSO's published results together with Danish clinical guidelines and international research. KiSO is an independent research project at the University of Copenhagen. If you want to read more, KiSO's own sources are the best place to start.

Read the studyUniversity of Copenhagen news on the results (Danish)KiSO's free leaflet on menopause (Danish)About KiSO
Source: University of Copenhagen, 30 October 2025.Women in Healthy Transition (KISO) Survey: a cohort of 153,800 women aged 45–59 years living in Denmark. European Journal of Epidemiology, 2025.
YOUR OWN COURSE

The numbers show how many experience it. Ryma shows your individual journey.

Talk or write to Ryma when symptoms show up. Ryma gathers them over time, so you can see your own patterns and bring them to your doctor.

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