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Perimenopause: The Ovary’s Frustrating Grand Finale

Women in midlife increasingly hear the words “estrogen deficiency” spoken as the ultimate in bad news. Everyone knows that low estrogen levels cause heart disease, osteoporosis, Alzheimer’s and frigidity. But as Dr. Susan Love, the influential breast surgeon, feminist advocate and now deceased author of Dr.

Susan Love’s Hormone Book asserts, “If estrogen deficiency’s a disease, all men have it!”(1) Also, it is hard to see how “estrogen deficiency” even exists. Why? Because, progesterone deficiency would always occur before “estrogen deficiency” since an estrogen peak is required before the ovary can release an egg and produce progesterone during the menstrual cycle

Our purpose here is, first, to put women’s midlife concerns into a new and more accurate hormonal picture. Specifically, I’d like to present information about high estrogen levels in perimenopause. Estrogen levels in perimenopause, in contrast to expectation, are not low, nor are they even normal. Rather they are higher than in the (sexiest) 20-something female!

Secondly, I’ll discuss how a woman can tell when her estrogen levels are high and out of balance with progesterone, the other important hormone for women.

Finally, we’ll review the many ways a woman can help herself through perimenopause, “Estrogen’s storm season”

What is perimenopause?

Women (and experts) have often called “menopause” everything they experience during the changing times of midlife and beyond. “Menopause” may also be used in the same way as “postmenopause”; this happens when the word “menopause” is inappropriately used to mean the last menstruation.

Menopause, defined accurately, means that a year has passed since a woman’s last menstrual period.

Now, we know that perimenopause is different than menopause, but how are they different? These normal life phases differ because perimenopausal women have had a period or some uterine bleeding within the last year. Perimenopausal hormones are also variable and often high compared with the normally low, and more steady levels in menopause.


Figure 1 shows line drawings of about a month of estrogen levels during the menstruating years (premenopause), when cycles and experiences are changing in perimenopause, and during menopause that starts a year after the final menstrual flow.


Although things like hot flushes and night sweats (vasomotor symptoms, VMS) and sleep problems occur in both perimenopause and menopause, some experiences, such as heavy flow, premenstrual symptoms and sore breasts, are very different. The Centre for Menstrual Cycle and Ovulation Research and many women and experts believe that it is important to use accurate names in describing midlife women’s reproductive phases.

Perimenopause refers to the long and changing time until it has been a year since the last flow. The first changes may be more heavy flow, night sweats, and waking the middle of the night or increased premenstrual symptoms. On average, perimenopause starts in the mid-40s and ends from ages 40-59 or at the average age in the early 50s. Perimenopause may last a couple, to more than 10 years. It also may start in women with predictable month-apart cycles (“very early perimenopause”) in women who have night sweats, sleep troubles and another typical change

The good news is that perimenopause ends! I survived a rough perimenopause. When I was in that difficult time, I learned, from my experiences that the experts had it all wrong about low perimenopausal estrogen levels! Despite all the evidence, that wrong concept persists.

What’s the evidence that perimenopausal estrogen levels are high?

A dozen or so studies in the last 20 years have set out to measure estrogen hormone levels in perimenopausal women. When all of the studies are put together in what is called a meta-analysis that compares average perimenopausal estrogen levels with those in young women, it is clear that perimenopausal estrogen levels are higher, and significantly so(2).


Figure 2 illustrates that average, within-study-centre estrogen levels are significantly higher in perimenopause (red), than in premenopause (yellow), especially in the latter portion of the menstrual cycle when women are ideally normally ovulating. These data were graphed from a Table in Prior JC, Endocrine Reviews 1998;19:397.


We also have population-based information about estrogen levels from 380 Australian midlife women randomly sampled from census rolls in Melbourne. These women were healthy, ages 45-55 (mean 49) years, all had menstruated in the last year and none used hormones. The estrogen tests were taken early in a cycle during flow and before estrogen’s midcycle peak(3). The data show each woman as a dot. Not only are most of estrogen levels as high or higher than for premenopausal women (the yellow around the bottom line in the graph), but many are even higher than the average midcycle peak estrogen levels (second, higher line). However, I was shock when I saw how the scientists summarize their data.

Perimenopause is characterized by dropping estrogen. . . levels”(4). They couldn’t “see” what they didn’t expect!


Figure 3 shows as bands of colour the levels of estrogen measured on cycle days 3-8 in 380 women who were ages 45-55 years. Menstrual Status Category 1 means regular periods, II and III changes in flow and cycle lengths, respectively, IV includes changes in both cycle lengths and flow, and V includes women 3 to less than 12 months without a period. Redrawn from(3).


The study we discussed above(3) also showed that a strange hormone called ‘inhibin’ was lower than normal. Inhibin is made by ovarian follicles (nests of estrogen-making cells surrounding an egg). Inhibin may decrease in midlife because the follicles have been in the ovary for longer. I believe the high estrogens in perimenopause occur largely because inhibin, the normal brake-type hormone, slacks off in its job of keeping the pituitary’s Follicle Stimulating Hormone (FSH) in line. FSH increases, stimulating many, rather than just a few, follicles at a time. The result is increased estrogen levels, lower progesterone and increased cycle unpredictability(3). All of the perimenopausal changes are because the “big plan” is to get rid of all the follicles left in our ovaries so that we don’t have periods in a nursing home.

How can a women know when her estrogen levels are high or out of balance with progesterone?

There are many clues and they differ between women, and in one woman over time. Early in the process of my perimenopause, I dreamed I was going to have a baby and woke thinking I had really lost it! At fifty, with my two children grown, the last thing in the world I wanted was to be pregnant. But after some thought, I began to understand that it was my subconscious self’s way of saying goodbye to the fertile part of my life.

Many of the things I felt in that dream, however, are also high estrogen signs: swollen and tender (sometimes lumpy) breasts, increased, stretchy vaginal mucus and a heavy pelvic feeling almost like cramps. High estrogen and progesterone levels in pregnancy are normal and necessary, but in the perimenopause, estrogen is high but progesterone is not. It is this imbalance that causes significant difficulties for many women.

Dr. Patricia Kaufert, a scientist from Winnipeg who decades ago did one of the best studies about what women experience during perimenopause, found that women were likely to have a flooding menstruation just before their periods changed from regular to skipping(4). But heavy flow, bleeding at shorter intervals than 3-weeks, continual spotting or flow with clotting and cramping are all signs that estrogen is too high and progesterone is too low. Any period is too heavy if you soak more than 16 pads or tampons.

It is sometimes normal to feel breast tenderness in the front or nipple area when estrogen hits its high midcycle peak. But swollen breasts most of the time, or front-of-the-breast soreness for more than a couple of days of a month, means high estrogen.

During perimenopause many women occasionally become forgetful and sometimes can’t remember what they were saying. We now know that stress makes for memory problems. And the high estrogen levels of perimenopause (on top of the stressors of this major life transition) make cortisol and other stress levels higher. No wonder it feels like PMS-city! One nurse said it very well, “At (peri)menopause life can turn into one long pre-menstrual experience. Hormones slap you up against the doors of your unfinished business”(5). (italics added)

Are hot flushes/flashes and night sweats (vasomotor symptoms) from low estrogen?

If monthly periods tell a woman that her estrogen levels are normal, and if vasomotor symptoms (VMS) are caused by low estrogen levels, how come so many perimenopausal women start having night sweats when periods are perfect? The answer is that the brain has become used to the young normal or higher perimenopausal estrogen levels; when estrogen drops, the brain rebels. What happens with a hot flush is like what a drug addict goes through during withdrawal — a major brain discharge of stress and other hormones. It is this stress hormone discharge that causes the anxious feelings, nausea and chest pain as well as the feeling of heat/sweating that go with VMS. Also, randomized controlled trial evidence shows that life stress also triggers hot flushes. So, if someone tells you your night sweats are all in your head, just tell them, “you’re darn tootin they are”!

I first twigged that I was perimenopausal when I woke abruptly one dark November morning feeling MAD! I looked for a cause — my dog and my partner were sleeping soundly, all was quiet in the house and the neighborhood. But my heart was pounding, my legs wouldn’t lie still and I was ready to do battle. Then I felt a weak and woozy wave of heat and began to sweat. A day later my period started, and I had no more night sweats until the day before my next period. I had learned an important thing — in the “very early perimenopause” when periods are still regular, night sweats are a clue that your period is coming.

Another new observation is that women who have increased premenstrual symptoms early in perimenopause are more likely to have a difficult time with VMS later. That information came from information discovered in the same Australian study we talked about earlier(6). We also have recently learned that downward estrogen swings trigger the negative moods that perimenopausal women sometimes experience.

What can women do to help themselves through the rough times in perimenopause?

The first and most important thing is to realize that, ready or not, this is a time of major change — change in body, even change in concept of one’s self A number of years ago I was captured on a National Film Board video “Is it hot in here?” saying I was only 22 times 2 (!) and was looking forward to menopause since it is normal! But, when perimenopause hit me, although my mind said okay, I went months of steadily sore breasts, and also through times of real sadness. Losing youth, fertility and even predictable periods is a justifiable reason for feeling blue. It will help women deal with this natural sadness if they can talk with friends, family and perhaps even a counselor about these important and often hidden deep feelings.

The next and most important thing is to take time to care for yourself. Take time out for exercise, meditation, a cup of coffee with a friend, or something that makes you happy. Say NO to more overtime, or continuing to make your 12-year old’s lunch...... Downward estrogen swings cause bone loss so I also urge women to take 3000 IU of vitamin D (depending on the climate and how much sun you get) at least in winter, and to get at least 1500 mg/day of calcium spread across meals and bedtime.

To help perimenopausal women deal with night sweats and sleep problems, get a prescription for oral micronized progesterone (progesterone) that is the same as our ovaries would normally make 300 mg at bedtime. This recommendation is based on a recently published CeMCOR randomized, placebo-controlled 4-month trial in 189 perimenopausal women This trial also showed progesterone caused a significant decrease in perimenopausal interference with usual life, and no increase in depression. Although it is a risk for uterine cancer to take estrogen alone, and without progesterone, it is perfectly safe, as a treatment, to take progesterone alone.

Most important is what can women do about periods, flooding, cramps and the risk for anemia? If a woman is regularly soaking over 12 pads or tampons during her whole period, I suggest she take one iron tablet (at the same time as vitamin C) a day. Iron tablet can be purchased without a prescription but you will have to ask the pharmacist in most places. For cramps, take ibuprofen 400 mg at the first hint, and repeat with 200 mg more as cramps start to return For very heavy menstruation that almost a third of perimenopausal women experience, you can also ask for a prescription for daily progesterone (300 mg at bedtime) for 3-months. It will make flow lighter but is unlikely to make it stop


So, let’s review. We have talked about the puzzle in perimenopause of high rather than low estrogen and the paradox that many believe, without scientific evidence, that estrogen treatment will help. Now I hope you will be able to recognize when estrogen is too high and will know that, although it may be miserable, it is normal and will pass. Perimenopausal women will also now understand why they get night sweats, or breast tenderness or mood swings. Most importantly, for night sweats, sleep problems and overall peri- menopausal interference with life, progesterone 300 mg at bedtime daily will importantly and safely help. Most of all, understand that you, like me, can survive even a very difficult perimenopause!

Finally, as Ursula LeGuin, the now-deceased, wise, science fiction writer wrote, “The woman who is willing to make that change must become pregnant with herself, at last” (7).

Reference List

  1. Love, S. & Lindsey, K. Dr Susan Love's menopause and hormone book: making informed choices. Vol. 3 (Three Rivers Press, N.Y., 2003).
  2. Prior, J. C. Perimenopause: The complex endocrinology of the menopausal transition. Endocrine Reviews 1998;19:397-428.
  3. Burger, H. G. et al. The endocrinology of the menopausal transition: a cross-sectional study of a population-based sample. Journal of Clinical Endocrinology and Metabolism 1995;80:3537-3545.
  4. Kaufert PA, Gilbert P, Tate R: Defining menopausal status: the impact of longitudinal data. Maturitas 1987;9: 217-226.
  5. Kelsea M: Beyond the stethoscope: a nurse practitioner looks at menopause and midlife. In: Women of the 14th Moon: writings on menopause. Sumrall AC, Taylor D, eds. Freedom, California: The Crossing Press, 1991; 268-279.
  6. Guthrie JR, Dennerstein L, Hopper JL, Burger HG: Hot flushes, menstrual status, and hormone levels in a population-based sample of midlife women. Obstetrics and Gynecology 1996;88:437-442.
  7. LeGuin UK: The Space Crone. In: Women of the 14th Moon: writings on menopause. Sumrall AC, Taylor D, eds. Freedom, California: The Crossing Press,1991;3-6.
Dr. Jerilynn C. Prior, Scientific Director, Centre for Menstrual Cycle and Ovulation Research
Life Phase: 
Updated Date: 
October 5, 2023

Estrogen’s Storm Season: Stories of Perimenopause

Estrogen's Storm Season

by Dr. Jerilynn C Prior

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