Thank you for your question. It is indeed a puzzle. But let’s see if I can explain it to you. First of all, although the usual pattern for night sweats is that they start in later perimenopause and then persist for two or three years after the final menstrual period, that’s usual. Some of us, and I’m one of them, have continued to have night sweats and daytime hot flushes for many more than two or three years. That’s because the normal distribution of hot flushes has about 25% of women starting them when their cycles are still regular in perimenopause. And about 10% of women continue for more than 5 years, and 2% for more than 10 years.
What you really want to know is the answer to the “why me?” question and also, what can I do to make them better.
Before we get into the characteristics of women at increased risk and what helps them, let’s review what causes them. Hot flushes and night sweats are part of the same phenomenon of sudden sense of heat with/without sweating but often also with a feeling of agitation. Hot flushes are not caused by low estrogen levels, per se. They appear to be caused when the hypothalamus part of the brain—which has gotten used to higher levels of estrogen—sees a drop in that level. Only women who’ve had normal periods, been on estrogen therapy or birth control pills, or are very obese (because this causes higher estrogen levels) will be at risk for hot flushes. Women with early menopause that have never been estrogen-treated, won’t get hot flushes, for example.
Here’s what we know about those women who are particularly at risk. Women who have premenstrual symptoms early in perimenopause are at increased risk for hot flushes later in perimenopause (1-3 [1]). I think the reason is that those with mood, breast, fluid and appetite changes before flow are experiencing higher perimenopausal estrogen levels. A prospective study looking at hormone levels in women when they are having premenstrual symptoms and when they aren’t shows that higher estrogen levels and borderline lower progesterone levels make women most symptomatic (4 [1]).
The second risk factor is being heavier in weight (5;6;7 [1]). The reason is probably that the hypothalamus has gotten used to seeing higher estrogen levels because of the conversion of androgens to estrogens in our fat and muscle.
Another risk factor is being under social or environmental stress. The stress of being in a room with loud noises and watching troubling videos has been shown to experimentally increase the number of hot flushes women will experience (7 [1]). Also, women in a large study of perimenopause found that those women who had difficulty paying for basics were more likely to have hot flushes (6 [1]).
The biggest single reason for hot flushes persisting for years after menopause is that women have been treated with estrogen therapy and then suddenly stopped it. This sudden stopping of estrogen appears to be primarily a risk for women who have ever had hot flushes, but one of 20 women (5%) who said they’d never previously had them, developed mild symptoms after being on estrogen for only one month and having it abruptly stopped.
Usually the answer to “why me?” is unknown but it is highly likely it is a combination of mystery and the variables of previous high estrogen exposure, higher weight, greater stress or stopping estrogen suddenly.
The next part of your question is what to do about it. My personal judgment is that daytime mild flushes can be laughed at or ignored. It is the ones that wake you more than a couple of times a week that must be treated for well being.
First and foremost, it is important to learn and practice any of a variety of things that decrease the stress the hypothalamus sees. These include relaxation therapy, mind-body therapy, yoga or paced breathing and acupuncture.
The next thing, although the evidence it is effective is less, is to begin or increase your exercise. Conditioning exercise (the aerobic kind that raises your heart beat over 130 beats a minute) also acts to decrease the activation of the stress centres in the hypothalamus.
The next choice for me, and especially if the relaxation and exercise strategies have helped but not quite enough, is to start taking Remifemin which is a standardized form of black cohosh.
If hot flushes persist in bothering you, I’d ask your physician for a prescription for either medroxyprogesterone (MPA, Provera, and many other brand names) in a dose of 10 mg/d or oral micronized progesterone (Prometrium) in a dose of 300 mg at bedtime. We earlier showed that MPA 10 mg/d was as effective as conjugated equine estrogen (CEE, Premarin) 0.625 mg/d in treating the severe hot flushes after surgical menopause in menstruating women (8 [1]).
I hope this information is helpful to you.
Reference List
1. Morse CA, Dudley E, Guthrie J, Dennerstein L. Relationships between premenstrual complaints and perimenopausal experiences. Journal of Psychosomatic Obstetrics and Gynecology 1989;19:182-91.
2. 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(3):437-42.
3. Freeman EW, Sammel MD, Rinaudo PJ, Sheng L. Premenstrual syndrome as a predictor of menopausal symptoms. Obstet Gynecol 2004;103(5 Pt 1):960-6.
4. Wang M, Seippel L, Purdy RH, Backstrom T. Relationship between symptom severity and steroid variation in women with premenstrual syndrome: Study on serum pregnenolone, prenenolone sulfate, 5a-Pregnane-3,20-Dione, and 3a-Hydroxy-5a-Pregnan-20-one. J Clin Endocrinol Metab 1996;81:1076-82.
5. den Tonkelaar I, Seidell JC, van Noord PA. Obesity and fat distribution in relation to hot flashes in Dutch women from the DOM-project. Maturitas 1996;23:301-5.
6. Gold EB, Sternfeld B, Kelsey JL, Brown C, Mouton C, Reame N et al. Relation of demographic and lifestyle factors to symptoms in a multi-racial/ethnic population of women 40-55 years of age. Am.J.Epidemiol. 2000;152:463-73.
7. Swartzman LC, Edelberg R, Kemmann E. Impact of stress on objectively recorded menopausal hot flushes and on flush report bias. Health Psychology 1990;9:529-45.
8. Prior, J. C., Alojado, N., Vigna, Y. M., Barr, S. I., and McKay, D. W. Estrogen and progestin are equally effective in symptom control post-ovariectomy--a one-year, double-blind, randomized trial in premenopausal women. Program of the 76th Annual Meeting of the Endocrine Society, Anaheim, Ca. Abstract 12H, 411. 1994.
