Most women begin menopause between the ages of 45 and 55. The average age for menopause onset in the United States is 51 years old, according to the . Early menopause usually refers to onset before age 40.

Menopause occurs when your ovaries stop producing estrogen, the hormone that controls the reproductive cycle. A woman is in menopause when she hasn’t had a period for more than 12 months. But associated symptoms, such as hot flashes, start long before menopause during a period called perimenopause.

Anything that damages your ovaries or stops estrogen production can cause early menopause. This includes chemotherapy for cancer or an oophorectomy (removal of the ovaries). In these cases, your doctor will help prepare you for early menopause. But you can also go into menopause early even if your ovaries are still intact.

There are several known causes of early menopause, although sometimes the cause can’t be determined.

Genetics

If there’s no obvious medical reason for early menopause, the cause is likely genetic. Your age at menopause onset is likely inherited.

Knowing when your mother started menopause can provide clues about when you’ll start your own. If your mother started menopause early, you’re more likely than average to do the same. However, genes tell only half the story.

Lifestyle factors

Some lifestyle factors may have an impact on when you begin menopause. Smoking has antiestrogen effects that can contribute to early menopause. An of several studies showed that long-term or regular smokers are likely to experience menopause sooner. According to the , women who smoke may start menopause one to two years earlier than women who don’t smoke.

Body mass index (BMI) can also factor into early menopause. Estrogen is stored in fat tissue. Women who are very thin have fewer estrogen stores, which can be depleted sooner.

Some research also suggests that a vegetarian diet, lack of exercise, and lack of sun exposure throughout your life can all cause early onset of menopause.

Chromosome defects

Some chromosomal defects can lead to early menopause. For example, Turner syndrome (also called monosomy X and gonadal dysgenesis) involves being born with an incomplete chromosome. Women with Turner syndrome have ovaries that don’t function properly. This often causes them to enter menopause prematurely.

Other chromosomal defects can cause early menopause, too. This includes pure gonadal dysgenesis, a variation on Turner syndrome. In this condition, the ovaries don’t function. Instead, periods and secondary sex characteristics must be brought about by hormone replacement therapy (HRT), usually during adolescence.

Trisomy 13 and 18 are conditions in which the 13th or 18th pair of chromosomes has an extra chromosome. These conditions can also lead to early menopause. They usually cause severe developmental issues in addition to infertility.

Autoimmune diseases

Premature menopause can be a symptom of an autoimmune disease such as thyroid disease and rheumatoid arthritis. In autoimmune diseases, the immune system mistakes a part of the body for an invader and attacks it. Inflammation caused by some of these diseases can affect the ovaries. Menopause begins when the ovaries stop working.

Epilepsy

Epilepsy is a seizure disorder that stems from the brain. Women with epilepsy are more likely to experience premature ovarian failure, which leads to menopause. An found that in a group of women with epilepsy, about 14 percent of those studied had premature menopause, as opposed to 1 percent of the general population.

Early menopause can begin as soon as you start having irregular periods or periods that are noticeably longer or shorter than normal. Other symptoms of early menopause include:

  • heavy bleeding
  • spotting
  • periods that last longer than a week
  • a period after a year of no bleeding

In these cases, see your doctor to check for any other issues that might be causing these symptoms.

Other common symptoms of menopause include:

The beginning stages of menopause are called perimenopause. During this time, you may have irregular periods and other symptoms that come and go. You’re generally considered to be in menopause if you go 12 months without menstrual bleeding, and you don’t have another medical condition to explain your symptoms.

Tests aren’t usually needed to diagnose menopause. Most women can self-diagnose menopause based on their symptoms. But if you think you’re experiencing early menopause, you may want to see your doctor to be sure.

Your doctor can order hormone tests to help determine whether your symptoms are due to perimenopause or another condition. These are the most common hormones to check:

  • Estrogen. Your doctor may check your levels of estrogen, also called estradiol. In menopause, estrogen levels decrease.
  • Follicle-stimulating hormone (FSH). If your FSH levels are consistently above , and you haven’t menstruated for a year, it’s likely that you’ve reached menopause. However, a single elevated FSH test can’t confirm menopause on its own.
  • Thyroid-stimulating hormone (TSH). Your doctor may check your levels of TSH to confirm diagnosis. If you have an underactive thyroid (hypothyroidism), you’ll have TSH levels that are too high. Symptoms of the condition are similar to the symptoms of menopause.

reports that hormone tests are sometimes unhelpful because hormone levels still change and fluctuate during perimenopause. Even so, if you’re concerned about signs of menopause, NAMS suggests this is a good time for a full checkup with your doctor.

Early menopause generally doesn’t require treatment. However, there are treatment options available to help manage the symptoms of menopause or conditions related to it. They can help you deal with changes in your body or lifestyle more easily.

Some common treatments include:

  • Hormone replacement therapy (HRT). Systemic hormone therapy can prevent many common menopausal symptoms. Or you may take vaginal hormone products, usually in low doses, to help with vaginal symptoms of menopause.
  • Menopausal hormone therapy (MHT). Estrogen and progesterone supplements can help reduce menopause symptoms and bone loss.

These therapies can increase your chances of heart disease, stroke, or breast cancer. Talk to your doctor about these risks before undergoing HRT or MHT. Lower doses of hormones may decrease your risk.

Early menopause can’t usually be reversed, but treatment can help delay or reduce the symptoms of menopause.

Researchers are investigating new ways to help women who are in menopause to have children. In 2016, scientists in Greece announced a new treatment that enabled them to restore menstruation and retrieve eggs from a small group of women who were in perimenopause. This treatment as a way to “reverse” menopause, but little is known about how well it works.

The scientists reported treating more than 30 women, age 46 to 49, by injecting platelet-rich plasma (PRP) into their ovaries. PRP is sometimes used to promote tissue healing, but the treatment hasn’t been proven to be effective for any purpose. The scientists claimed the treatment worked for two-thirds of the women treated. However, the research has been for its small size and lack of control groups. Though the research might have potential for the future, it’s not a realistic treatment option right now.

Infertility is often the most obvious concern when you start menopause 10 or more years early. Yet, there are other health concerns. A steady stream of estrogen to your tissues has many uses. Estrogen increases “good” HDL cholesterol and decreases “bad” LDL cholesterol. It also relaxes blood vessels and prevents bones from thinning.

Losing estrogen earlier than normal can increase your risk of:

Discuss your concerns about these symptoms with your doctor. Because of these risks, women who enter menopause early are often prescribed hormone replacement therapy.

Starting menopause early can actually protect you from other diseases. These include estrogen-sensitive cancers such as breast cancer.

Women who enter menopause late (after age 55) are at greater risk of breast cancer than those who enter the transition earlier. This is because their breast tissue is exposed to estrogen for a longer time.

A genetic test may one day determine a person’s likelihood of early menopause. For now, though, only time will tell when you’ll start your transition. See your doctor for regular checkups, and be proactive about your reproductive health. Doing so can help your doctor ease the symptoms or decrease your risk factors for early menopause.

Seeing a therapist can also help you cope with any pain or anxiety you may feel during menopause.

Fertility and your options

If you’re interested in having children, you still have a few options for growing your family. These include:

  • adoption
  • egg donation
  • having a surrogate mother carry your child

A fertility specialist may also suggest procedures that can help you bear children. In vitro fertilization (IVF) is one procedure that allows you to have children even after the onset of menopause. Talk to your doctor before attempting IVF. Its risks and successes can be affected by many factors, including your age and overall health.