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Absence of Menstrual Periods

(Amenorrhea)

By

JoAnn V. Pinkerton

, MD, University of Virginia Health System

Last full review/revision Feb 2021| Content last modified Feb 2021
Click here for the Professional Version
Topic Resources

Having no menstrual periods is called amenorrhea.

Amenorrhea is normal in the following circumstances:

  • Before puberty

  • During pregnancy

  • While breastfeeding

  • After menopause

At other times, it may be the first symptom of a serious disorder.

Amenorrhea may be accompanied by other symptoms, depending on the cause. For example, women may develop masculine characteristics (virilization), such as excess body hair (hirsutism Hairiness In men, the amount of body hair varies greatly (see also Overview of Hair Growth), but very few men are concerned enough about excess hair to see a doctor. In women, the amount of hair that... read more Hairiness ), a deepened voice, and increased muscle size. They may have headaches, vision problems, or a decreased sex drive. They may have difficulty becoming pregnant.

In most women with amenorrhea, the ovaries do not release an egg. Such women cannot become pregnant.

If amenorrhea lasts a long time, problems similar to those associated with menopause Menopause Menopause is the permanent end of menstrual periods and thus of fertility. For up to several years before and just after menopause, estrogen levels fluctuate widely, periods become irregular... read more Menopause may develop. They include hot flashes, vaginal dryness, decreased bone density (osteoporosis Osteoporosis Osteoporosis is a condition in which a decrease in the density of bones weakens the bones, making breaks (fractures) likely. Aging, estrogen deficiency, low vitamin D or calcium intake, and... read more Osteoporosis ), and an increased risk of heart and blood vessel disorders. Such problems occur because in women who have amenorrhea, the estrogen level is low.

Types of amenorrhea

There are two main types of amenorrhea:

  • Primary: Menstrual periods never start.

  • Secondary: Periods start, then stop.

Usually if periods never start, girls do not go through puberty, and thus secondary sexual characteristics, such as breasts and pubic hair, do not develop normally.

If women have been having menstrual periods, which then stop, they may have secondary amenorrhea. Secondary amenorrhea is much more common than primary.

Hormones and menstruation

Menstrual periods are regulated by a complex hormonal system The female reproductive system consists of the external genital organs and internal genital organs. The breasts are sometimes considered part of the reproductive system. However, other parts... read more . Each month, this system produces hormones in a certain sequence to prepare the body, particularly the uterus, for pregnancy. When this system works normally and there is no pregnancy, the sequence ends with the uterus shedding its lining, producing a menstrual period Menstrual Cycle Menstruation is the shedding of the lining of the uterus (endometrium) accompanied by bleeding. It occurs in approximately monthly cycles throughout a woman's reproductive life, except during... read more . The hormones in this system are produced by the following:

  • The hypothalamus (part of the brain that helps control the pituitary gland)

  • The pituitary gland, which produces luteinizing hormone and follicle-stimulating hormone

  • The ovaries, which produce estrogen and progesterone

Other hormones, such as thyroid hormones and prolactin (produced by the pituitary gland), can affect the menstrual cycle.

The most common reason for no menstrual periods in women who are not pregnant or breastfeeding is

  • Malfunction of any part of this hormonal system

When this system malfunctions, the ovaries do not release an egg. The type of amenorrhea that results is called anovulatory amenorrhea.

Less commonly, the hormonal system is functioning normally, but another problem prevents periods from occurring. For example, menstrual bleeding may not occur because the uterus is scarred or because a birth defect, fibroid, or polyp blocks the flow of menstrual blood out of the vagina.

High levels of prolactin, which stimulates the breasts to produce milk, can result in no periods.

Causes

Amenorrhea can result from conditions that affect the hypothalamus, pituitary gland, ovaries, uterus, cervix, or vagina. These conditions include hormonal disorders, birth defects, genetic disorders, and drugs.

Which causes are most common depends on whether amenorrhea is primary or secondary.

Primary amenorrhea

The disorders that cause primary amenorrhea are relatively uncommon, but the most common are

Genetic disorders include

Genetic disorders and birth defects that cause primary amenorrhea may not be noticed until puberty. These disorders cause only primary amenorrhea, not secondary.

Sometimes puberty is delayed in girls who do not have a disorder, and normal periods simply begin at a later age. Such delayed puberty may run in families.

Secondary amenorrhea

The most common causes are

Pregnancy is the most common cause of amenorrhea among women of childbearing age.

The hypothalamus may malfunction for several reasons:

The pituitary gland may malfunction because

  • It is damaged.

  • Levels of prolactin are high.

Antidepressants, antipsychotic drugs, oral contraceptives (sometimes), or certain other drugs can cause prolactin levels to increase, as can pituitary tumors and some other disorders.

Less common causes of secondary amenorrhea include chronic disorders (particularly of the lungs, digestive tract, blood, kidneys, or liver), some autoimmune disorders, cancer, HIV infection, radiation therapy, head injuries, a hydatidiform mole (overgrowth of tissue from the placenta), Cushing syndrome, and malfunction of the adrenal glands. Scarring of the uterus (usually due to an infection or surgery), polyps, and fibroids can also cause secondary amenorrhea.

Evaluation

Doctors determine whether amenorrhea is primary or secondary. This information can help them identify the cause.

Warning signs

Certain symptoms are cause for concern:

When to see a doctor

Girls should see a doctor within a few weeks if

  • They have no signs of puberty (such as breast development or a growth spurt) by age 13.

  • Periods have not started by age 15 in girls who are growing normally and have developed secondary sexual characteristics.

Such girls may have primary amenorrhea.

If girls or women of childbearing age have had menstrual periods that have stopped, they should see a doctor if they have

  • Missed 3 menstrual periods

  • Fewer than 9 periods a year

  • A sudden change in the pattern of periods

Such women may have secondary amenorrhea. Doctors always do a pregnancy test when they evaluate women for secondary amenorrhea. Women may wish to do a home pregnancy test before they see the doctor.

What the doctor does

Doctors first ask about the medical history, including the menstrual history. Doctors then do a physical examination. What they find during the history and physical examination often suggests a cause of amenorrhea and the tests that may need to be done (see table Some Causes and Features of Amenorrhea Some Causes and Features of Amenorrhea Having no menstrual periods is called amenorrhea. Amenorrhea is normal in the following circumstances: Before puberty During pregnancy While breastfeeding read more ).

For the menstrual history, doctors determine whether amenorrhea is primary or secondary by asking the girl or woman whether she has ever had a menstrual period. If she has, she is asked how old she was when the periods started and when the last period occurred. She is also asked to describe the periods:

  • How long they lasted

  • How often they occurred

  • Whether they were ever regular

  • How heavy they were

  • Whether her breasts were tender or she had mood changes related to periods

If a girl has never had a period, doctors ask

  • Whether breasts have started to develop

  • Whether she has had a growth spurt

  • Whether pubic and underarm hair (signs of puberty) has appeared

  • Whether any other family member has had abnormal periods

This information enables doctors to rule out some causes. Information about delayed puberty and genetic disorders in family members can help doctors determine whether the cause is a genetic disorder.

Doctors ask about other symptoms that may suggest a cause and about use of drugs, exercise, eating habits, and other conditions that can cause amenorrhea.

During the physical examination, doctors determine whether secondary sexual characteristics have developed. A breast examination is done. A pelvic examination is done to determine whether genital organs are developing normally and to check for abnormalities in reproductive organs.

Doctors also check for symptoms that may suggest a cause such as

  • A milky discharge from both nipples: Possible causes include pituitary disorders and drugs that increase levels of prolactin (a hormone that stimulates milk production).

  • Headaches, hearing loss, and partial loss of vision or double vision: Possible causes include tumors of the pituitary gland or hypothalamus.

  • Development of masculine characteristics, such as excess body hair, a deepened voice, and increased muscle size: Possible causes include polycystic ovary syndrome, tumors that produce male hormones, and use of drugs such as synthetic male hormones (androgens), antidepressants, or high doses of synthetic female hormones called progestins.

  • Hot flashes, vaginal dryness, and night sweats: Possible causes include premature menopause, a disorder that causes the ovaries to malfunction, radiation therapy, and use of a chemotherapy drug.

  • Shakiness (tremors) with weight loss or sluggishness with weight gain: These symptoms suggest a thyroid disorder.

Table
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Table
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Testing

In girls or women of childbearing age, the first test is

  • A pregnancy test

If pregnancy is ruled out, other tests are done based on results of the examination and the suspected cause.

If girls have never had a period (primary amenorrhea) and have normal secondary sexual characteristics, testing begins with ultrasonography to check for birth defects that could block menstrual blood from leaving the uterus. If birth defects are unusual or difficult to identify, magnetic resonance imaging (MRI) may be done.

Tests are usually done in a certain order, and causes are identified or eliminated in the process. Whether additional tests are needed and which tests are done depend on results of the previous tests. Typical tests include

For hysteroscopy, doctors insert a thin viewing tube through the vagina and cervix to view the interior of the uterus. This procedure can be done in a doctor's office or in a hospital as an outpatient procedure.

For hysterosalpingography, x-rays are taken after a substance that can be seen on x-rays (a radiopaque contrast agent) is injected through the cervix into the uterus and fallopian tubes. Hysterosalpingography is usually done as an outpatient procedure in a hospital radiology suite.

If hormones trigger menstrual bleeding, the cause may be malfunction of the hormonal system that controls menstrual periods or premature menopause. If hormones do not trigger bleeding, the cause may be a disorder of the uterus or a structural abnormality preventing menstrual blood from flowing out.

If symptoms suggest a specific disorder, tests for that disorder may be done first. For example, if women have headaches and vision problems, MRI of the brain is done to check for a pituitary tumor.

Treatment

When amenorrhea results from another disorder, that disorder is treated if possible. With such treatment, menstrual periods sometimes resume. For example, if an abnormality is blocking the flow of menstrual blood, it is usually surgically repaired, and periods resume. Some disorders, such as Turner syndrome and other genetic disorders, cannot be cured.

If women have a Y chromosome, doctors recommend surgical removal of both ovaries because having a Y chromosome increases the risk of ovarian germ cell cancer Ovarian cancer, which typically starts on the surface of the ovaries, is not usually diagnosed until it is advanced. Ovarian cancer may not cause symptoms until it is large or has spread. If... read more . Ovarian germ cell cancer starts in the cells that produce eggs (germ cells) in the ovaries.

If a girl's periods never started and all test results are normal, she is examined every 3 to 6 months to check on the progression of puberty. She may be given a progestin and sometimes estrogen to start her periods and to stimulate the development of secondary sexual characteristics, such as breasts.

Problems associated with amenorrhea may require treatment, such as

Key Points

  • Various conditions can disrupt the complex hormonal system that regulates the menstrual cycle, causing menstrual periods to stop.

  • Doctors distinguish between primary amenorrhea (periods have never started) and secondary amenorrhea (periods started, then stopped).

  • The first test is a pregnancy test.

  • Unless a woman is pregnant, other testing is usually required to determine the cause of amenorrhea.

  • Problems related to amenorrhea (such as a low estrogen level) may also require treatment to prevent later health problems.

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