What are the signs of perimenopause? You’re in your 40s, you wake up in a sweat at night, and your periods are erratic and often accompanied by heavy bleeding: Chances are, you’re going through perimenopause. Many women experience an array of symptoms as their hormones shift during the months or years leading up to menopause — that is, the natural end of menstruation. Menopause is a point in time, but perimenopause (peri, Greek for “around” or “near” + menopause) is an extended transitional state. It’s also sometimes referred to as the menopausal transition, although technically, the transition ends 12 months earlier than perimenopause (see “Stages of reproductive aging” below).

What is perimenopause?

Perimenopause has been variously defined, but experts generally agree that it begins with irregular menstrual cycles — courtesy of declining ovarian function — and ends a year after the last menstrual period.

Perimenopause varies greatly from one woman to the next. The average duration is three to four years, although it can last just a few months or extend as long as a decade. Some women feel buffeted by hot flashes and wiped out by heavy periods; many have no bothersome symptoms. Periods may end more or less abruptly for some, while others may menstruate erratically for years. Fortunately, as knowledge about reproductive aging has grown, so have the options for treating some of its more distressing features.

Perimenopause and estrogen

The physical changes of perimenopause are rooted in hormonal alterations, particularly variations in the level of circulating estrogen.
During our peak reproductive years, the amount of estrogen in circulation rises and falls fairly predictably throughout the menstrual cycle. Estrogen levels are largely controlled by two hormones, follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH stimulates the follicles — the fluid-filled sacs in the ovaries that contain the eggs — to produce estrogen. When estrogen reaches a certain level, the brain signals the pituitary to turn off the FSH and produce a surge of LH. This in turn stimulates the ovary to release the egg from its follicle (ovulation). The leftover follicle produces progesterone, in addition to estrogen, in preparation for pregnancy. As these hormone levels rise, the levels of FSH and LH drop. If pregnancy doesn’t occur, progesterone falls, menstruation takes place, and the cycle begins again.

Hot flashes during perimenopause

Most women don’t expect to have hot flashes until menopause, so it can be a big surprise when they show up earlier, during perimenopause. Hot flashes — sometimes called hot flushes and given the scientific name of vasomotor symptoms — are the most commonly reported symptom of perimenopause. They’re also a regular feature of sudden menopause due to surgery or treatment with certain medications, such as chemotherapy drugs.

Hot flashes tend to come on rapidly and can last from one to five minutes. They range in severity from a fleeting sense of warmth to a feeling of being consumed by fire “from the inside out.” A major hot flash can induce facial and upper-body flushing, sweating, chills, and sometimes confusion. Having one of these at an inconvenient time (such as during a speech, job interview, or romantic interlude) can be quite disconcerting. Hot flash frequency varies widely. Some women have a few over the course of a week; others may experience 10 or more in the daytime, plus some at night.

Most American women have hot flashes around the time of menopause, but studies of other cultures suggest this experience is not universal. Far fewer Japanese, Korean, and Southeast Asian women report having hot flashes. In Mexico’s Yucatan peninsula, women appear not to have any at all. These differences may reflect cultural variations in perceptions, semantics, and lifestyle factors, such as diet.

Although the physiology of hot flashes has been studied for more than 30 years, no one is certain why or how they occur. Estrogen is involved — if it weren’t, estrogen therapy wouldn’t relieve vasomotor symptoms as well as it does — but it’s not the whole story. For example, researchers have found no differences in estrogen levels in women who have hot flash symptoms and those who don’t. A better understanding of the causes of hot flashes in perimenopause could open the way to new, nonhormonal treatments. Hormone therapy quells hot flashes, but it’s not risk-free.

By our late 30s, we don’t produce as much progesterone. The number and quality of follicles also diminishes, causing a decline in estrogen production and fewer ovulations. As a result, by our 40s, cycle length and menstrual flow may vary and periods may become irregular. Estrogen may drop precipitously or spike higher than normal. Over time, FSH levels rise in a vain attempt to prod the ovaries into producing more estrogen.

Although a high FSH can be a sign that perimenopause has begun, a single FSH reading isn’t a reliable indicator because day-to-day hormone levels can fluctuate dramatically.

Perimenopause symptoms

It can be difficult to distinguish the hormonally based symptoms of perimenopause from more general changes due to aging or common midlife events — such as children leaving home, changes in relationships or careers, or the death or illness of parents. Given the range of women’s experience of perimenopause, it’s unlikely that symptoms depend on hormonal fluctuations alone.

Hot flashes and night sweats. An estimated 35%–50% of perimenopausal women suffer sudden waves of body heat with sweating and flushing that last 5–10 minutes, often at night as well as during the day. They typically begin in the scalp, face, neck, or chest and can differ dramatically among women who have them; some women feel only slightly warm, while others end up wringing wet. Hot flashes often continue for a year or two after menopause. In up to 10% of women, they persist for years beyond that.

Vaginal dryness. During late perimenopause, falling estrogen levels can cause vaginal tissue to become thinner and drier. Vaginal dryness (which usually becomes even worse after menopause) can cause itching and irritation. It may also be a source of pain during intercourse, contributing to a decline in sexual desire at midlife.

Uterine bleeding problems. With less progesterone to regulate the growth of the endometrium, the uterine lining may become thicker before it’s shed, resulting in very heavy periods. Also, fibroids (benign tumors of the uterine wall) and endometriosis (the migration of endometrial tissue to other pelvic structures), both of which are fueled by estrogen, may become more troublesome.

Sleep disturbances. About 40% of perimenopausal women have sleep problems. Some studies have shown a relationship between night sweats and disrupted sleep; others have not. The problem is too complex to blame on hormone oscillations alone. Sleep cycles change as we age, and insomnia is a common age-related complaint in both sexes.

Mood symptoms. Estimates put the number of women who experience mood symptoms during perimenopause at 10%–20%. Some studies have linked estrogen to depression during the menopausal transition, but there’s no proof that depression in women at midlife reflects declining hormone levels. In fact, women actually have a lower rate of depression after age 45 than before. Menopause-related hormone changes are also unlikely to make women anxious or chronically irritable, although the unpredictability of perimenopause can be stressful and provoke some episodes of irritability. Also, some women may be more vulnerable than others to hormone-related mood changes. The best predictors of mood symptoms at midlife are life stress, poor overall health, and a history of depression.

Other problems. Many women complain of short-term memory problems and difficulty concentrating during the menopausal transition. Although estrogen and progesterone are players in maintaining brain function, there’s too little information to separate the effects of aging and psychosocial factors from those related to hormone changes.

What to do about perimenopause symptoms

Several treatments have been studied for managing perimenopausal symptoms. Complementary therapies are also available, but research on them is limited and the results are inconsistent.

Vasomotor symptoms. The first rule is to avoid possible triggers of hot flashes, which include warm air temperatures, hot beverages, and spicy foods. You know your triggers best. Dress in layers so you can take off clothes as needed. There’s clear evidence that paced respiration, a deep breathing technique, helps alleviate hot flashes. The most effective treatment for severe hot flashes and night sweats is estrogen. Unless you’ve had a hysterectomy, you’ll likely need to take a progestin to reduce the risk of developing endometrial cancer. Low-dose estrogen by pill or patch — for example, doses that are less than or equal to 0.3 milligrams (mg) conjugated equine estrogen, 0.5 mg oral micronized estradiol, 25 micrograms (mcg) transdermal (patch) estradiol, or 2.5 mcg ethinyl estradiol — works for many women. Other low-dose estradiol-based products include a skin lotion applied to the legs (Estrasorb) and a gel applied to the arms (Estrogel), both available by prescription.

Hormonal irregularities. If you need contraception and don’t smoke, you can take low-dose birth control pills until menopause (see “Irregular periods and heavy bleeding”). Another advantage of these pills is that they regulate your menses and suppress the erratic hormonal ups and downs of perimenopause; some women report feeling more even-tempered while taking them.

Severe hot flashes. Women with severe hot flashes who don’t want or can’t take a hormonal therapy may get some relief from newer antidepressants such as Effexor (venlafaxine) or certain selective serotonin reuptake inhibitors (SSRIs), for example, Prozac (fluoxetine) and Paxil (paroxetine); the epilepsy drug Neurontin (gabapentin); or clonidine, a blood pressure drug. Some of these medications have side effects that may limit their usefulness. Also, some SSRIs can interfere with the metabolism of tamoxifen in certain women.
Irregular periods and heavy bleeding. If you have irregular bleeding and don’t want to become pregnant, low-dose birth control pills are a good choice. By suppressing ovulation, they modulate menstrual flow, regulate periods, and stabilize endometriosis. They also protect against endometrial and ovarian cancers, stave off hot flashes, reduce vaginal dryness, and prevent bone loss. If you have abnormal bleeding, such as daily or very heavy bleeding, see your gynecologist.

Oral contraceptives can be taken until menopause. To help determine whether you’ve reached menopause, your clinician may order a blood test of your FSH level, taken after seven days off the pill. But the only wholly reliable measure is 12 months off hormones without a menstrual period.

Vaginal dryness. Low-dose contraceptives or vaginal estrogen (in a cream, ring, tablet, or gel) can help relieve vaginal dryness, but hormonal treatment is not the only approach. Vaginal moisturizers such as Replens, applied twice weekly, increase vaginal moisture, elasticity, and acidity. Continued sexual activity also seems to improve vaginal tone and helps maintain the acidic environment that protects it against infections. Lubricants such as K-Y Jelly, Astroglide, and K-Y Silk-E can make intercourse less painful.