Hot flashes, night sweats, loss of regular menstrual periods and sleep problems. These familiar symptoms of menopause appear in most women around age 50. But if they arise before age 40—which happens for about 1 in 100 women—it’s a sign that something’s wrong. Early symptoms like these could be a sign of a little-understood condition called primary ovarian insufficiency (POI).

Most women with POI are infertile . They’re also at risk for bone fractures and heart disease. And many aren’t aware they have POI.

“Symptoms of POI can be missed because young women may not realize they’re having symptoms similar to menopause. They may not think hot flashes are worth mentioning to a doctor,” says Dr. Lawrence M. Nelson, a researcher and physician at NIH. “Some teens and young women think of the menstrual cycle as a nuisance, and they don’t mind missing periods. They don’t take it seriously, and that’s a mistake.” Missing or irregular periods are a major sign of POI.

When young women have POI, their ovaries don’t work normally. They stop regularly releasing eggs and cut back production of estrogen and other reproductive hormones . These same things happen when older women go through menopause, which is why the symptoms are similar. As with menopause, POI symptoms can often be relieved by hormone replacement therapy, usually an estrogen patch. And as with menopause, POI puts women at risk for bone loss. But with a proper diagnosis of POI and early treatment, bone health can be protected.

POI was previously known as “premature menopause” or “premature ovarian failure.” But research has since shown that ovarian function is unpredictable in these women, sometimes turning on and off, which is why many physicians now prefer the term primary ovarian insufficiency.

Many aspects of POI remain mysterious—including its cause. Only 10% of cases can be traced to either to a genetic condition or to autoimmunity—a disorder in which the immune system attacks the body’s own tissues.

Nelson’s research has shown that the unexpected loss of fertility often leads to grief and symptoms of anxiety and depression in women with POI. But a recent study from his lab suggests that most young women and teens with POI still have immature eggs in their ovaries. The finding raises the possibility that future treatments might be developed to restore fertility to some affected women. Even without treatment, up to 1 in 10 women with POI may unexpectedly become pregnant after their condition is diagnosed.

Irregular or stopped periods might be a sign of other conditions, including eating disorders or too much exercise. A simple blood test for elevated levels of a molecule called follicle stimulating hormone (FSH) can help to confirm a diagnosis of POI.

“Having regular menstrual periods is a sign that the ovaries are working properly,” says Nelson. “If that isn’t happening, it’s important for girls and young women to talk to their health care provider and find out why.”

Symptoms of POI

See a health care provider if you’re a woman under age 40 and you experience these symptoms:

• Absent or irregular periods
• Hot flashes or night sweats
• Irritability or poor concentration
• Decreased sex drive
• Painful sex, drying of the vagina
• Infertility

Menopause that happens before age 40 is called premature menopause. Menopause that happens between 40 and 45 is called early menopause. About 5% of women naturally go through early menopause. Smoking and certain medicines or treatments can cause menopause to come earlier than usual.

Early or premature menopause happens when ovaries stop making hormones and periods stop at a younger age than usual (the average age for menopause in the United States is 52). This can happen naturally or for a medical reason, such as when both ovaries are removed in a hysterectomy.

Early and premature menopause can have the same causes. The only difference is the age at which it happens. Menopause that happens before age 45 is called early menopause. Menopause that happens before age 40 is called premature menopause.

Women who have gone through early or premature menopause cannot get pregnant.

Early or premature menopause can happen on its own for no clear reason, or it can happen because of certain surgeries, medicines, or health conditions.

Reasons for early or premature menopause can include:

• Family history. Women with a family history of early or premature menopause are more likely to have early or premature menopause.
• Smoking. Women who smoke may reach menopause as much as two years before nonsmokers. They may also get more severe menopause symptoms. Research suggests that women who have early or premature menopause and smoke die about two years earlier than nonsmoking women.
• Chemotherapy or pelvic radiation treatments for cancer. These treatments can damage your ovaries and cause your periods to stop forever or just for a while. You also may have trouble getting pregnant or not be able to get pregnant again. Not all women who have chemotherapy or radiation will go through menopause. The younger a woman is at the time of chemotherapy or radiation, the less likely she is to go through menopause.
• Surgery to remove the ovaries. Surgical removal of both ovaries, called a bilateral oophorectomy (OH-fuh-REK-tuh-mee), may cause menopausal symptoms right away. Your periods will stop after this surgery, and your hormone levels will drop quickly. You may have strong menopausal symptoms, like hot flashes and less sexual desire.
• Surgery to remove the uterus. Some women who have a hysterectomy, which removes the uterus, can keep their ovaries. If this happens, you will no longer have periods, and you cannot get pregnant. But you will probably not go through menopause right away because your ovaries will continue to make hormones. Later on, you might have natural menopause a year or two earlier than expected.
• Certain health conditions:
  
  • Autoimmune diseases, such asthyroid disease and rheumatoid arthritis. Although rare, the body’s immune system, which normally fights off diseases, may mistakenly attack the ovaries and keep them from making hormones.
  • HIV and AIDS. Women with HIV whose infection is not well controlled with medicine may experience early menopause. Women with HIV may also have more severe hot flashes than women without HIV.
  • Missing chromosomes. Women born with missing chromosomes or problems with chromosomes can go through menopause early. For example, women with the condition called Turner’s syndrome are born without all or part of one X chromosome, so their ovaries do not form normally at birth and their menstrual cycles, including the time around menopause, may not be normal.
  • Chronic fatigue syndrome. Women with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) have extreme tiredness, weakness, muscle and joint pain, memory loss, headache, unrefreshing sleep, and other symptoms. Research has found that women with ME/CFS are more likely to have early or premature menopause.

You know you have gone through menopause when you have not had your period for 12 months in a row. If you think you may be reaching menopause early, talk to your doctor or nurse.

• Your doctor or nurse will ask you about your symptoms, such as hot flashes, irregular periods, sleep problems, and vaginal dryness.
• Your doctor or nurse may give you a blood test to measure estrogen and related hormones, like follicle-stimulating hormone (FSH). You may choose to get tested if you want to know whether you can still get pregnant. Your doctor or nurse will test your hormone levels in the first few days of your menstrual cycle (when bleeding begins).

Estrogen is used by many parts of a woman’s body. As levels of estrogen decrease, you could have various symptoms. Many women experience mild symptoms that can be treated by lifestyle changes such as avoiding caffeine or carrying a portable fan. Some women don’t require any treatment at all, but for others, symptoms can be more severe. The severity of symptoms varies greatly around the world and by race and ethnicity.

Here are the most common changes you might notice at midlife. Some may be part of aging rather than directly related to menopause.

Change in your period. This might be what you notice first. Your periods may no longer be regular. They may be shorter or last longer. You might bleed more or less than usual. These are all normal changes, but to make sure there isn’t a problem, see your doctor if:

• Your periods happen very close together.
• You have heavy bleeding.
• You have spotting.
• Your periods last more than a week.
• Your periods resume after no bleeding for more than a year.

Hot flashes. Many women have hot flashes, which can last for many years after menopause. They may be related to changing estrogen levels. A hot flash is a sudden feeling of heat in the upper part or all of your body. Your face and neck may become flushed. Red blotches may appear on your chest, back, and arms. Heavy sweating and cold shivering can follow. Hot flashes can be very mild or strong enough to wake you up (called night sweats). Most hot flashes last between 30 seconds and 10 minutes. They can happen several times an hour, a few times a day, or just once or twice a week.

Bladder control. A loss of bladder control is called incontinence. You may have a sudden urge to urinate, or urine may leak during exercise, sneezing, or laughing. The first step in treating incontinence is to see a doctor. Bladder infections also can occur in midlife.

Sleep. Around midlife, some women start having trouble getting a good night’s sleep. Maybe you can’t fall asleep easily, or you wake too early. Night sweats might wake you up. And if you wake up during the night, you might have trouble falling back to sleep.

Vaginal health and sexuality. After menopause, the vagina may become drier, which can make sexual intercourse uncomfortable. You may also find that your feelings about sex are changing. You could be less interested, or you could feel freer and sexier because after one full year without a period, you can no longer become pregnant. However, you could still be at risk for sexually transmitted diseases (STDs), such as gonorrhea or HIV/AIDS. Your risk for an STD increases if you have sex with more than one person or with someone who has sex with others. If so, make sure your partner uses a condom each time you have sex.

Mood changes. You might feel moodier or more irritable around the time of menopause. Scientists don’t know why this happens. It’s possible that stress, family changes such as growing children or aging parents, a history of depression, or feeling tired could be causing these mood changes. Talk with your primary care provider or a mental health professional about what you’re experiencing. There are treatments available to help.

Your body seems different. Your waist could get larger. You could lose muscle and gain fat. Your skin could become thinner. You might have memory problems, and your joints and muscles could feel stiff and achy. Researchers are exploring such changes and how they relate to hormones and growing older.

In addition, for some women, symptoms may include aches and pains, headaches, and heart palpitations. Follow up with a doctor. Because menopausal symptoms may be caused by changing hormone levels, it is unpredictable how often women will experience symptoms and how severe they will be.

Menopause is a point in time 12 months after a woman's last period. The years leading up to that point, when women may have changes in their monthly cycles, hot flashes, or other symptoms, are called the menopausal transition or perimenopause.

The menopausal transition most often begins between ages 45 and 55. It usually lasts about seven years but can be as long as 14 years. The duration can depend on lifestyle factors such as smoking, age it begins, and race and ethnicity. During perimenopause, the body's production of estrogen and progesterone, two hormones made by the ovaries, varies greatly.

The menopausal transition affects each woman uniquely and in various ways. The body begins to use energy differently, fat cells change, and women may gain weight more easily. You may experience changes in your bone or heart health, your body shape and composition, or your physical function.

Women who go through menopause early may have symptoms or health problems similar to those of regular menopause.

But some women with early or premature menopause may also have:

• Higher risk of serious health problems, such as heart disease and osteoporosis, since women will live longer without the health benefits of higher estrogen levels. Talk to your doctor or nurse about steps to lower your risk for these health problems.
• More severe menopause symptoms. Talk to your doctor or nurse about treatments to help with symptoms if they affect your daily life.
• Sadness or depression over the early loss of fertility or the change in their bodies. Talk to your doctor if you have symptoms of depression, including less energy or a lack of interest in things you once enjoyed that lasts longer than a few weeks. Your doctor or nurse can recommend specialists who can help you deal with your feelings. Your doctor or nurse can also discuss options, such as adoption or donor egg programs, if you want to have children.

Breastfeeding can offer many health benefits for women and their babies. Now there's another potential one.

A recent study found that women who breastfeed may have a lower risk of early menopause. Early menopause—menopause before age 45— can lead to faster bone loss, cognitive decline, and heart disease.

The study, funded by the National Institutes of Health, found that women who breastfed exclusively for seven to 12 months had a 28% lower risk of early menopause than those who breastfed for less than a month. Women who breastfed for a total of 25 months or more had a 26% lower risk.

The study's results also suggest that pregnancy itself may reduce the risk of early menopause. Compared with women who had never been pregnant or who had been pregnant for less than six months, those who had a full-term pregnancy had an 8% lower risk of early menopause. Those who had two pregnancies had a 16% lower risk, and those who had three pregnancies had a 22% lower risk.

Researchers theorize that reproductive events that slow or halt ovulation, such as pregnancy and breastfeeding, may be associated with delayed menopause.