Four hundred fifty: That’s about how many periods you can expect in your lifetime. This monthly event, in which the uterine lining is expelled if an egg is unfertilized, is a complicated business, involving numerous hormonal players that can affect your weight, your temper, and your sex drive.
What Is a Period, Anyway?
Your brain tells the pituitary gland to release two chemical messengers, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), about two weeks after your period starts. The hormones contact the ovaries, triggering a follicle, one of their microscopic egg-containing pouches, to develop and release the egg (a.k.a. ovulation). In the process, the ovaries secrete estrogen and progesterone, which, among other things, tell the uterus to get ready with a lining in case of pregnancy. If the egg isn’t fertilized, your body decides that the fun is over and hormonal levels drop, signaling the uterine lining to shed. And voilà—your period.
When your period changes, you may worry that something is amiss, but most likely you’re perfectly healthy. Here are the shifts that you can expect over the 38-odd years you have a period, and the times they warrant a closer look.
In Your 20s
What’s common: After undergoing some irregular patches in your teens as your ovaries sputter to life, your menstrual cycle usually (but not always) becomes regular. Your period comes every 25 to 32 days and lasts three to seven days. “Yet even a woman whose period comes like clockwork will occasionally have a cycle that varies,” says Angela Dempsey, an ob-gyn at the Medical University of South Carolina, in Charleston.
What to Watch For
- Skipped periods: Being relatively new to the game, you might assume that disappearing acts are part of the deal. But missed periods could be a sign that you are exercising too much or have lost too much weight—or that you’re pregnant, of course. In rarer cases, missed periods, or ones that vary in intensity and come with weight gain, thinning hair, excessive body hair, or depression, could indicate polycystic ovary syndrome (PCOS), a treatable disorder that affects up to one in 10 women yet goes undiagnosed at least half the time.
See your doctor if: You skip three periods in a row and pregnancy tests are negative.
- Irregular bleeding: Spotting or heavy bleeding may signal a polyp or a fibroid (both growths in the cervix or the uterus and usually benign) or a cervical lesion (which could be benign or due to a virus or cancer). Low progesterone can also lead to irregular bleeding.
See your doctor if: You’re spotting between cycles or after intercourse, or your periods are much heavier than usual.
- Painful cramps: Cramps are normal, but women in their 20s report worse ones than older women; scientists don’t know why. You can take a nonsteroidal anti-inflammatory drug (NSAID), like ibuprofen or naproxen, to tame them, or you may be able to ward them off entirely if you take a dose the day before you expect your period. You can also try omega-3 fatty acid supplements, which helped reduce cramps in a study published in the International Journal of Gynecology and Obstetrics in 2012. (Aim for two grams daily.) Early research suggests that vitamin D may also be a cramp-fighter. (Try to get 600 international units, or IU, a day.)
See your doctor if: Cramps get in the way of your daily functioning. This can signal fibroids or endometriosis, an often painful condition in which uterine cells grow outside the uterus.
In Your 30s
What’s common: Your early 30s feature cycles much like those of your 20s. Things change when you hit your mid- to late 30s—or, for some women, the early 40s—when occasional hormonal surprises start to occur: rude awakenings due to night sweats, sudden breast tenderness, or an oddball 24-day cycle. Behind the scenes, your ovaries are beginning to show their age. “You have fewer functional eggs, and subsequently you may have less estrogen,” says Judi Chervenak, M.D., an associate professor of gynecology and women’s health at Montefiore Medical Center at Albert Einstein College of Medicine, in the Bronx. Even though only one follicle typically matures into an egg each cycle (or occasionally two, as with fraternal twins), about 1,000 follicles are lost every month in a process called atresia, in which they self-destruct and are absorbed by the body. So while at age 18 you had about 400,000 follicles in your ovaries, by 37 that number has plummeted to 25,000. Your chances of infertility jump from about 8 percent in your late teens and 20s to 25 percent in your late 30s, according to the National Center for Health Statistics. These changes affect your periods, too.
What to Watch For
- Raging PMS: Amazingly, researchers still don’t really know why premenstrual syndrome (PMS) happens, but they do know that lifestyle and diet can exacerbate the symptoms. For one thing, sleep deprivation and stress cause you to pump out extra cortisol, upsetting your hormonal balance and leading to estrogen-dominant symptoms like bloating and sore breasts, says Sara Gottfried, a gynecologist in San Francisco and the author of The Hormone Cure ($28, amazon.com).
Protecting your sleep (aim for seven to nine hours) and getting exercise (think 30 minutes most days) can help ease PMS. So can tweaking your diet: Cutting back on caffeine and limiting alcohol to three drinks a week is a good start. “It can be a game changer,” says Marcelle Pick, an ob-gyn nurse practitioner in Yarmouth, Maine, and the author of Is It Me or My Hormones? ($25, amazon.com). “Most people do not understand that what we put in our bodies has a gigantic impact on hormonal health.”
Supplements can also help. About 1,300 milligrams of calcium daily has been found to decrease negative moods, water retention, food cravings, and pain, and 200 milligrams of magnesium a day can help prevent bloating.
Acupuncture may also bring relief: A study published in 2012 in Clinical & Experimental Obstetrics & Gynecology found that breast pain, muscle aches, and pelvic pain decreased or disappeared after three months of treatment. Laurie Binder, an acupuncturist and ob-gyn nurse practitioner in Santa Monica, California, recommends monthly treatments one or two weeks before menstruation.
See your doctor if: Lifestyle changes don’t help. She may suggest hormonal contraception (the Pill, a vaginal ring, or a patch) or, for disruptive mood changes, an antidepressant. (Research has found that you may be able to limit taking an antidepressant to the two weeks before your period.
- Heavy periods: If you are experiencing heavier-than-usual periods, this can signal the presence of cysts, fibroids, or a thyroid disorder.
See your doctor if: You need to change protection every two to three hours or double up (with a pad and a tampon).
- Lags between periods: It’s common in your 30s for cycles to get shorter (going from, say, 28 days to 25). But big gaps can signal premature ovarian failure—that’s menopause before age 40, a growing problem that affects up to 4 percent of women. The resulting low estrogen can not only compromise fertility but also lead to other problems, including bone loss.
See your doctor if: You go two to three months between periods.
In Your 40s and Beyond
What’s common: The 40s are the decade in which your reproductive system starts winding down in the transitional phase known as perimenopause. Your ovaries will officially close up shop somewhere in your 50s. The average age of menopause (defined as your very last period) is between 51 and 52 years old. Over the course of your 40s and into your 50s, you have progressively fewer eggs left, and the remaining ones are less robust. Throughout this phase, the senior-citizen eggs become increasingly deaf to the signals that they’re getting from the brain: Some months they hear just fine and your period is the way it was in the old days. Other months they respond with a big “Huh?” and miss the invitation to ovulate, which means you won’t menstruate. Your brain, unaccustomed to being ignored, cranks up its messaging and turns out even more FSH and LH until the ovaries finally respond. And once they get through loud and clear, watch out. After a few months of skipping a period—or spotting lightly—the uterine-lining buildup can lead to major-league flooding in subsequent months. “Irregularity is the new normal,” says Dempsey.
While your eggs are releasing diminishing amounts of progesterone and estrogen, the levels change from day to day, since sometimes there’s no ovulation and other times there’s double. This makes for an erratic ride of symptoms—from moodiness to hot flashes. On top of that, you can’t be sure you’ve reached menopause until a full year after it happens, says Margery Gass, M.D., the executive director of the North American Menopause Society, in Cleveland. Missing periods may leave you thinking that you’ve reached your destination, but 6 to 11 months later you might find yourself frantically scavenging for a tampon.
To estimate when to expect all of this, find out when your mother’s periods stopped: This is one of the best predictors of when you’ll hit menopause. Perimenopause spans about three to eight years before that.
What to Watch For
- Pelvic pain and heavy bleeding: Zigzagging estrogen levels can cause flare-ups of conditions like endometriosis and fibroids. If the bleeding is frequent and accompanied by a slowing metabolism, hair loss, dry skin, constipation, or poor concentration, this could indicate thyroid problems. These symptoms are so common, in fact, that this stage is sometimes referred to as “thyropause.”
See your doctor if: You have dull or sharp pain in your abdomen or pelvis or are suddenly having much heavier periods. If you don’t have an underlying issue, you can treat heavy bleeding with the hormone-containing Mirena IUD, which is approved by the U.S. Food and Drug Administration for that purpose.
- Pregnancy!: Don’t be fooled: Even if you’re having irregular cycles, you can still become pregnant. According to data from the Guttmacher Institute, a reproductive-health research organization, next to women in their teens and early 20s, women in their 40s have the highest rate of unintended pregnancy.