It is not a disease, and it does not mean that a person is infertile, but it can be a sign of a health problem that needs some attention.
During pregnancy, menstruation also stops, and it is common for it to stop during breastfeeding, too.
If menstruation does not occur at times when people normally expect it to, this is amenorrhea.
Types of amenorrhea
There are two types of amenorrhea: primary and secondary.
Amenorrhea refers to a lack of menstruation, either because periods never started or because they stop.
Primary amenhorrea is when periods do not start during puberty.
According to the National Institutes of Health, if periods do not start by the age of 16 years, the person should seek medical help.
Primary amenorrhea is rare. In the United States, it affects fewer than 0.1 percent of individuals.
This is when periods start, but then they cease to occur.
This is normal during pregnancy or while breastfeeding, but it may also mean that there is a problem.
In the U.S., secondary amenorrhea is thought to affect around 4 percent of women during their lifetime.
One missing period is not usually a sign of a health problem, although many people will ask for a pregnancy test if this happens.
A doctor will consider secondary amenorrhea if an individual:
- used to have regular periods and then does not have any for 3 months
- used to have irregular periods and then does not have any for 6 months
Causes of amenorrhea
The cause will probably be different for primary and secondary amenorrhea.
A common cause of primary amenorrhea is a family history of delayed menstruation. However, sometimes there is a genetic problem.
Genetic conditions that can stop the ovaries from working properly include:
- Turner syndrome
- androgen insensitivity syndrome, which leads to high levels of testosterone
- Müllerian defects
A Müllerian defect is a malformation of the reproductive organs. The uterus and fallopian tubes do not form as they should.
There may be a structural problem relating to the genitals that is present from birth. Occasionally, the uterus and fallopian tubes may be missing. Sometimes, there are problems of fusion, in which the tubes do not come together correctly.
In Müllerian agenesis, or Mayer-Rokitansky-KusterHauser (MRKH) syndrome, the ovaries, breasts, and clitoris form correctly, but there is no vaginal opening, and the cervix and uterus may not be properly formed.
In this case, reproductive development will not follow the normal pattern, and menstruation may not be possible.
Reasons for amenorrhea include pregnancy, changes in weight and exercise, medication, and some health conditions.
Menstruation may stop for a number of reasons.
When BMI falls below 19, the risk of developing secondary amenorrhea increases significantly.
Weight loss, exercise, and stress
Serious weight loss can result from a physical illness or an eating disorder.
Stringent exercise can cause secondary amenorrhea. It is common among competitive long-distance runners and professional ballet dancers.
Severe emotional upheaval or extreme stress can also cause a woman's periods to stop.
Some medications, such as progesterone-only contraceptives and a number of psychiatric drugs may cause periods to stop.
Other medications that affect menstruation include:
Long-term health conditions
Amenorrhea can also result from a long-term illness, such as:
- polycystic ovary syndrome (PCOS)
- premature ovarian failure
- thalamic pituitary problems
Pituitary problems or an underactive thyroid can lead to a hormone imbalance, and this can result in menstrual problems.
These could be due to:
- a benign or cancerous tumor in the pituitary gland
- an over- or under-active thyroid gland
The main symptom is a lack of menstruation.
However, depending on the cause, other symptoms may occur.
In those with primary amenorrhea, there may be a lack of breast development.
Anyone who experiences these symptoms should seek medical advice.
Amenorrhea is a symptom, not an illness. The doctor will aim to find out why there is no menstruation.
If an individual has not started menstruating by the age of 16 years, a doctor may ask about their family history and carry out a number of tests.
These will include tests to assess the levels of the following hormones:
- follicle stimulating hormone (FSH)
- luteinizing hormone (LH)
- thyroid stimulating hormone (TSH)
They will also carry out a physical examination.
If you have had regular periods previously and then no menstruation for 3 months, consider seeing a doctor.
A diagnosis for secondary amenorrhea will focus on the underlying cause of the problem.
Before carrying out any tests, the physician may ask questions to find out:
- at what age menstruation started
- whether the person is sexually active
- if pregnancy is a possibility
- if weight loss or weight gain has occurred, and what kind of exercise routine the person follows
- the length and regularity of the menstrual cycle and whether bleeding is heavy or light
They may then recommend a number of tests, depending on what the cause appears to be.
These may include:
- a pregnancy test
- a thyroid function test
- ovary function test
- androgen and other hormone tests
Imaging tests may include:
- an MRI, CT, or ultrasound scan
- a hysteroscopy, in which the doctor passes a thin, lighted camera through the vagina and cervix to examine the uterus from the inside
Treatment will depend on the cause.
Treatment for primary amenorrhea may start with watchful waiting, depending on the person's age and the result of the ovary function test. If there is a family history of late menstruation, periods may start in time.
If there are genetic or physical problems that involve the reproductive organs, surgery may be necessary. This will not guarantee, however, that normal menstrual cycles will occur.
This will depend on the underlying cause.
Lifestyle factors: If the person has been exercising excessively, a change of exercise plan or diet may help to stabilize the monthly cycle.
Stress: If emotional or mental stress is a problem, counseling may help.
Excessive weight loss: This can happen for different reasons. The person may need a professionally supervised weight gain regime. If an eating disorder is a possibility, treatment may include a weight-gain regime and counseling sessions with a psychiatrist and a nutritionist or dietitian.
Some health conditions can cause weight loss. A doctor may test for these and offer treatment as appropriate.
Underactive thyroid: If menstruation stops because of an underactive thyroid, the doctor may prescribe treatment with thyroxine, a thyroid hormone.
Polycystic ovary syndrome (PCOS): The doctor will suggest appropriate treatment. If PCOS has led to excess weight, they may recommend a weight-loss diet.
Premature ovary failure: Hormone replacement therapy (HRT) may cause menstruation to return.
Menopause: Menopause starts around the age of 50 years, but sometimes it can start as early as 40 years. Family history can affect this.
If menopause starts early, there is a higher risk of osteoporosis. The person may need treatment to prevent this complication.
Menstruation can stop for a number of reasons. It does not necessarily mean that a person is infertile and can never conceive.
If regular periods cease for 3 months or more, or if irregular periods stop for at least 6 months, the individual should seek medical advice.
In many cases, treatment is available.