When perimenopause starts



One of the most perplexing experiences of women approaching midlife is that they notice changes in their body that medical providers can't or don't validate. These individuals might still be having regular menstrual cycles, but noticing significant disruption in other areas. The changes they notice seem hormonal. But they aren't in perimenopause yet, according to their providers, because their periods are still coming with regularity (although perhaps a little closer together than they used to).


Women might notice they've started awakening mid-sleep. Their breasts may become tender for several days a month. They may have new night sweats. Or they may have mood changes such as anxiety or irritability. For some, new headaches or nausea have appeared. Or they get premenstrual cramps and heavy periods when they never had those before. What can explain all this if not perimenopause?


Maybe our definition of perimenopause needs adjusting. It may be helpful to think of the end of the reproductive years as a three stage process:

  • In the first stage, menstrual cycles are regular but hormonal changes have begun, and women may notice symptoms of this hormonal change. These changes can start in the late 30s to early 40s.

  • In the second stage, a period has come at least 6 days earlier or later than in a typical cycle. For most women, this may start in the mid 40s. However, individuals who don't have regular menstrual periods, such as those with a hormonal IUD, will not be able to identify menstrual changes.

  • In the final stage of perimenopause, 60 days or more will pass between cycles.

Most providers are aware of the second and third stages above, but not the first. This is troubling for women who want help understanding or managing the changes they are noticing in their body. Research does show predictable hormone changes are already occurring in the late reproductive period, even though periods are regular. Prior to the first early or delayed period, progesterone has significantly decreased from peak reproductive levels, while estrogen peaks are increasing (not decreasing, as many assume). The symptoms women report with these hormonal changes include:

  • Heavier menstrual flow

  • Shorter menstrual cycles

  • Breast tenderness

  • Premenstrual cramps

  • Mid-sleep awakening

  • Night sweats

  • Increased premenstrual headaches

  • New anxiety or irritability

  • Weight gain with no changes to exercise or food intake

According to researcher Jerrilyn Prior, a person in the mid 30s or older who has developed any three of the above symptoms should consider themself to be in early perimenopause. This is also a useful method of identifying perimenopause for women who no longer get periods because of medical treatments (like hysterectomy, endometrial ablation, or hormonal IUD).


If you think you are in the perimenopausal phase, remember that while the end of the reproductive years is normal and expected, suffering is not required. If you're struggling, make an appointment, hopefully with someone who understands the menopause transition, to figure out how to get the support you need. They can help address your concerns including:

  • how long will this go on?

  • what if I still desire pregnancy?

  • how can I feel better?

Perimenopause looks and feels different for different women. If you would like to, share in the comments below how perimenopause has affected you.

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