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), 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 may develop. They include hot flashes, vaginal dryness, decreased bone density (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. 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. 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.
Causes of Amenorrhea
Conditions that can cause amenorrhea include hormonal disorders, birth defects, genetic disorders, medications, and illicit drugs.
The most common reason for amenorrhea in women who are not pregnant or breastfeeding is
Malfunction of any part of the hormonal system (hypothalamus, pituitary gland, and ovaries)
When this system malfunctions, the ovaries do not release an egg. The type of amenorrhea that results is called ovulatory dysfunction.
Amenorrhea can also result from conditions that affect the uterus, cervix, or vagina.
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 (Asherman syndrome), because the cervix is narrowed (cervical stenosis), or because a birth defect blocks the flow of menstrual blood out of the vagina.
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
A genetic disorder
A birth defect of the reproductive organs that blocks the flow of menstrual blood (such as an imperforate hymen)
Genetic disorders include
Overproduction of male hormones by the adrenal glands (congenital adrenal hyperplasia)
Genital disorders that result in ambiguous—neither male nor female—genitals (pseudohermaphroditism or true hermaphroditism)
Disorders that result in having a Y chromosome (which normally occurs only in males).
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
Breastfeeding
Malfunction of the hypothalamus
Premature menopause (primary ovarian insufficiency)
Malfunction of the pituitary gland or the thyroid gland
Use of certain medications, such as birth control pills (oral contraceptives), antidepressants, or antipsychotic medications
Pregnancy is the most common cause of amenorrhea among women of childbearing age.
The hypothalamus may malfunction for several reasons:
Stress or excessive exercise (as done by competitive athletes, particularly women who participate in sports that involve maintaining a low body weight)
Poor nutrition (as may occur in women who have an eating disorder or who have lost a significant amount of weight)
Mental disorders (such as depression or obsessive-compulsive disorder)
Radiation therapy to the brain or a brain injury
The pituitary gland may malfunction because
It is damaged by a disorder (such as a tumor) or a head injury.
Levels of prolactin are high.
Antidepressants, antipsychotic medications, oral contraceptives (sometimes), or certain other medications can cause prolactin levels to increase, as can pituitary tumors and some other disorders.
The thyroid gland may cause amenorrhea if it is underactive (called hypothyroidism) or overactive (called hyperthyroidism).
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.
Genetic disorders, such as Fragile X syndrome, may cause menstrual periods to stop early (premature menopause).
Evaluation of Amenorrhea
Doctors determine whether amenorrhea is primary or secondary. This information can help them identify the cause.
Warning signs
Certain symptoms in girls and women with amenorrhea are cause for concern:
Development of masculine characteristics, such as excess body hair, a deepened voice, and increased muscle size
Vision problems
An impaired sense of smell (which may be a symptom of Kallmann syndrome)
A milky nipple discharge that occurs spontaneously (that is, without the nipple's being squeezed or otherwise stimulated)
A significant change in weight
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 3 years after breasts begin to develop.
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).
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 many days they lasted
How often they occurred
Whether they were ever regular
How regular they have been in the last 3 to 12 month
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 and. if so, at what age
Whether she has had a growth spurt and. if so, at what age
Whether pubic and underarm hair (signs of puberty) has appeared and. if so, at what age
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 medications (including prescription and over-the-counter medications, dietary supplements, and opioids), 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 medications 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 medications 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 chemotherapy.
Shakiness (tremors) with weight loss or sluggishness with weight gain: These symptoms suggest a thyroid disorder.
Erosion of tooth enamel, enlarged salivary glands in the cheeks (parotid glands), and inflammation of the esophagus: These symptoms suggest an eating disorder, such as anorexia nervosa.
Testing
In girls or women of childbearing age, testing may include
A pregnancy test
Blood tests to measure hormone levels
An imaging test or procedure to examine the reproductive system (such as ultrasonography or hysteroscopy)
Sometimes use of hormonal medications to determine whether they trigger a menstrual period
A pregnancy test is sometimes done even in girls who have not had a period or reported sexual activity. 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 hormonal blood tests, a physical examination, and 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. 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. Whether additional tests are needed and which tests are done depend on results of the previous tests. Typical tests include
Blood tests to measure levels of certain hormones including prolactin (to check for high levels, which can interfere with menstrual periods), thyroid hormones (to check for thyroid disorders), follicle-stimulating hormone (to check for problems with pituitary or hypothalamus function), and male hormones (to check for disorders that cause masculine characteristics to develop)
Imaging tests of the abdomen and pelvis to look for a tumor in the ovaries or adrenal glands (usually ultrasongraphy but sometimes computed tomography (CT) or MRI)
Examination of chromosomes in a sample of tissue (such as blood) to check for genetic disorders
A procedure to view the inside of the uterus or fallopian tubes (hysteroscopy or hysterosalpingography) and check for blockages in these organs and other abnormalities
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.
Hormones (progestin or estrogen plus progestin) may be given by mouth to try to trigger menstrual bleeding. If the 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.
Treatment of Amenorrhea
When amenorrhea results from a specific disorder, that disorder is treated if possible. With such treatment, menstrual periods sometimes resume. For example, if a woman has a hormonal disorder that can be treated, such as an underactive thyroid gland (hypothyroidism), or an abnormality that is blocking the flow of menstrual blood and can be surgically repaired, her periods usually resume.
If a girl's periods never started and all test results are normal, she should see a health care practitioner every 3 to 6 months to check on the progression of puberty. She may be given a medication called 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
Difficulty getting pregnant (infertility): It may be necessary to take hormonal medications to trigger release of an egg (ovulation) if pregnancy is desired.
Symptoms and long-term effects of estrogen deficiency, such as decreased bone density (osteoporosis), vaginal dryness, and an increased risk of heart and blood vessel disorders: Hormonal medications (called menopausal hormone therapy or hormone replacement therapy) may be considered.
Excess body hair: Treating the disorder causing amenorrhea may help, or excess hair may be managed with hair removal techniques.
The effects of estrogenbisphosphonates
Rarely, girls have a genetic disorder that causes problems with hormonal function. Genetic disorders, such as Turner syndrome, 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 germ cell cancer starts in the cells that produce eggs (germ cells) in the ovaries.
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 usually 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, such as fractures due to decreased bone density (osteoporosis).
