What Is Amenorrhea?

Medically Reviewed by Jabeen Begum, MD on January 17, 2025
Written by Keri Wiginton
9 min read

Amenorrhea is when you don’t get your period despite being old enough to have a menstrual cycle. It’s normal during certain stages of life, such as pregnancy or menopause.

Unlike irregular periods, amenorrhea means your period stops completely. While it’s not a disease, the absence of a regular period could be a sign of a medical condition that needs treatment. So, it’s important to talk to your doctor if you have it.

There are two types of amenorrhea:

Primary amenorrhea. This is when people assigned female at birth don’t get their first period by the age of 15.

Secondary amenorrhea. This is when you’ve had periods in the past, but they stop for three or more months in a row.

There are many reasons why you might not get your first period by the time you turn 15. Most of the time, it has to do with hormone levels or a problem with the reproductive system. 

Here are some possible causes of primary amenorrhea: 

Ovarian problems. Ovaries that don’t work properly can delay your first menstrual cycle.

Brain or spinal cord issues. Problems with the central nervous system can affect the hormone signals needed for a period.

Pituitary gland problems. The pituitary gland is a part of your brain that controls hormones involved in menstruation.

Structural differences. Sometimes the uterus, vagina, or other female sex organs form in a way that prevents menstruation.

Certain genetic conditions can also cause amenorrhea. This includes:

Turner syndrome. When you’re born with a missing or damaged X chromosome, your ovaries may not develop properly or make enough estrogen.

Androgen insensitivity. This happens when the body doesn’t respond to hormones needed for growth and development.

Sometimes, there’s no clear reason why someone’s first period is late. It’s still important to talk to your doctor to figure out what’s going on and find out what to do next.

Common causes of secondary amenorrhea (when you’ve had normal periods but stop getting them) include:

Other causes of secondary amenorrhea include:

If you've had your uterus or ovaries removed, you will stop having a period.

Post-pill amenorrhea

You may not get a period if you take birth control pills continuously. This means you take “active” pills (with hormones in them) each week. Your menstrual cycle usually returns to normal when you stop taking the pill. But it may not get back on track right away.

If you stop taking birth control pills and don’t get your period for several months, you may have post-pill amenorrhea. This happens because the hormones in birth control interrupt your regular menstrual cycle. It can take time for your body to adjust.

What other symptoms might come with amenorrhea?

The biggest sign is missing your period. Other things can happen with amenorrhea, but it depends on the cause. You may also have these symptoms:

  • Extra body hair (hirsutism)
  • Acne
  • Hair thinning or loss
  • Headache
  • Slow breast growth
  • Milky discharge from your breasts
  • Vision changes
  • Not ovulating

Hypothalamic amenorrhea, or functional hypothalamic amenorrhea (FHA), happens when your period stops because of problems with your hypothalamus. That’s a part of your brain that helps control your hormones, including the ones that manage your menstrual cycles.

About 1.62 million women and people assigned female at birth get hypothalamic amenorrhea. It causes 20%-35% of cases where periods stop in people aged 18-44.

What causes hypothalamic amenorrhea? 

There are a few common reasons your hypothalamus might stop working as it should: 

Exercising a lot. Intense or frequent workouts can throw off your hormones.

Stress. Mental stress can affect brain signals that trigger hormones.

Not eating enough. Your body needs fuel to support a possible pregnancy.

Disordered eating. Conditions such as anorexia or binge eating can affect your period.

Hypothalamic amenorrhea symptoms 

Other than a missed period, you might not notice signs of hypothalamic amenorrhea right away. But it can lower estrogen, which can lead to issues such as:

  • Feeling depressed or anxious
  • High cholesterol or blood pressure
  • Bone thinning
  • Trouble getting pregnant (infertility)

If hypothalamic amenorrhea and low estrogen go untreated for months or years, you’re more likely to have heart and blood vessel problems (cardiovascular disease) and serious bone loss (osteoporosis).

How do you diagnose hypothalamic amenorrhea?

To figure out if you have hypothalamic amenorrhea, your doctor will ask about your medical history, lifestyle habits, and symptoms. They’ll also rule out other possible medical causes of missed periods, such as: 

  • Pregnancy
  • Thyroid issues
  • High prolactin levels (hyperprolactinemia)
  • Premature ovarian insufficiency
  • Polycystic ovarian syndrome (PCOS)
  • Pituitary gland problems

Your doctor might: 

  • Take some blood to check hormone levels
  • Do imaging tests to check for problems with ovaries or other reproductive organs
  • Ask questions about your stress levels, eating patterns, and exercise habits

By taking your whole mental and physical health into account, they can figure out what treatment and support you might need to get your period back.

Hypothyroidism is when your thyroid gland doesn’t make enough thyroid hormone. This tiny gland in your neck plays a big role in controlling hormones that affect many body processes, such as your metabolism, heart rate, and menstrual cycle. 

When your thyroid hormone levels are low, your body may make more prolactin — the hormone that helps with making breast milk (lactation). High levels can interfere with ovulation — the process where your ovaries release an egg.

If you don’t ovulate regularly, your periods might stop or become irregular. 

What about hyperthyroidism and amenorrhea?

On the flip side, hyperthyroidism — when your thyroid makes too much hormone — can also cause period problems. It might make your cycles lighter, less regular, or absent.

Since many things can cause amenorrhea, it may take time to find the exact reason behind your missed periods.

Your doctor will ask about your medical history and do a physical and pelvic exam. If you’re sexually active, they’ll likely begin with a pregnancy test to rule that out.

They may ask you questions such as:

  • How old were you when you had your first period?
  • Do any of your family members have a history of missed periods?
  • What is the typical length of your menstrual cycle?
  • Have you gained or lost weight recently?
  • Do you exercise a lot? Are you an athlete?
  • Are you under a lot of stress? 
  • What are your eating habits like?

It may take several kinds of tests to find the cause of amenorrhea, such as:

Blood tests. These measure the level of hormones such as follicle-stimulating hormone (FSH), thyroid-stimulating hormone, prolactin, and androgens. Too much or too little of these sex hormones can interfere with the menstrual cycle.

Imaging tests. Ultrasound, CT, and MRI can look for problems with your reproductive organs or detect tumors.

Hormone challenge test. Your doctor will give you hormonal medication. If you don’t have vaginal bleeding after stopping it, low estrogen could be the cause of amenorrhea.

Hysteroscopy. Your doctor will put a small lighted camera through your vagina and cervix to look for anything unusual inside your uterus.

Genetic screening. These tests check for genetic issues, such as changes to the FMR1 gene, that can stop the ovaries from working properly.

Chromosome tests (karyotype). These look for missing, extra, or rearranged cells in certain chromosomes that could explain your symptoms (Turner Syndrome, for example).

Certain things can raise your chances of missing periods, whether it’s primary or secondary amenorrhea.

You’re more likely to have amenorrhea if you have:

  • Family history of early menopause or missed periods
  • Past medical procedures that affect your uterus
  • Structural differences in your uterus, cervix, ovaries, or vagina
  • A change in the FMRI gene (Fragile X syndrome)

Other factors that raise your risk of amenorrhea include:

  • Intense physical activity, especially if you’re training for sports
  • Problems maintaining a healthy weight (underweight or obesity)
  • Trouble with stress management 
  • History of disordered eating (anorexia nervosa or binge eating disorder)

Other common amenorrhea risk factors include:

  • Pregnancy or breastfeeding
  • Perimenopause or menopause
  • Ongoing use of hormonal birth control, such as shots, implants, or intrauterine devices (IUDs)
  • Antipsychotics or antidepressants
  • Cancer treatment (chemotherapy or radiation)
  • Some other prescription drugs, such as meds for blood pressure or allergies 

If you’re worried you might be at risk for amenorrhea, check in with your doctor. They can assess your risk and guide you on what to do.

Treatment for amenorrhea will focus on the condition that causes it. Hormone replacement therapy or birth control pills can help start your menstrual cycle again. A thyroid or pituitary disorder can be treated with medication. Physical abnormalities may need surgery.

If things such as stress, weight gain or loss, or depression are affecting your menstrual cycle, you can take an active role in your treatment by taking steps to manage it. Friends, family, or your doctor may be able to help you.

You can help your doctor trace the cause of your amenorrhea by tracking changes in your cycle and symptoms and sharing this information with them. Tell them about your medications as well as changes in your diet, exercise habits, and stress levels.

You may not have any problems from a few missed periods. But untreated amenorrhea can sometimes lead to more serious health issues.

Here’s what can happen:

Fertility problems. If you don’t ovulate (release eggs), it’s harder to get pregnant.

Bone loss. Missed periods can lower estrogen, which weakens bones.

Heart issues. Your cholesterol, blood pressure, and blood sugar may go up if you have amenorrhea due to low estrogen. This makes heart disease more likely.

Mental health issues. Stress about missing periods is common. Hormonal imbalances can also cause mood and thinking problems, like depression and anxiety. 

Pelvic pain. Some causes of amenorrhea, like anatomical issues, can cause pain.

Endometrial hyperplasia and cancer. Without regular periods, the uterine lining can become too thick due to excess estrogen. This condition, called endometrial hyperplasia, can sometimes lead to uterine cancer.

Amenorrhea is when you don’t have a period, even though you’re old enough to have one. Natural causes include pregnancy, breastfeeding, and menopause.

If you haven’t had a period in at least three months and don’t know why, see your regular doctor or OB/GYN. It could be a sign of a hidden health issue that needs treatment. Your doctor can help you figure out what’s going on and what to do next.

How do I get my period back?

Treatment depends on what’s causing amenorrhea. If you have ovarian problems, hormone therapy can help get things back on track. Stress management, good nutrition, and maintaining a healthy weight may work in other cases. The best way to get your period back is to talk to your doctor.

How much delay in periods is normal?

Most periods get off schedule every now and then. But you should talk to your doctor if you haven’t had a period for three months or more and you don’t know why, or if you’ve reached age 15 and are yet to get your first period.