Amenorrhea: Causes, Symptoms, Diagnosis, Treatment, and Complications

Amenorrhea means the absence of menstrual periods. It may occur when a girl has not started menstruating by the expected age, or when a person who previously had periods stops having them. Amenorrhea is not a disease by itself. It is a sign that something has interrupted the normal menstrual cycle, and the cause may be natural, lifestyle-related, hormonal, structural, medication-related, or medical.

Amenorrhea refers to the absence of a menstrual period when one would normally be expected. It may be a temporary or long-term issue, depending on the cause. The absence of menstruation is not a disease by itself but often a symptom of something else going on in the body. Image Credit: ibreakstock from Getty Images via Canva.com

Amenorrhea: Key Facts in Summary

• Amenorrhea means absent menstrual periods. It may be primary, when periods have not started by the expected age, or secondary, when periods stop after previously occurring.


• Common causes include pregnancy, breastfeeding, menopause, stress, excessive exercise, low body weight, eating disorders, PCOS, thyroid disease, high prolactin, pituitary problems, uterine scarring, some medications, and cancer treatments.


• Symptoms may include missed periods, hot flashes, nipple discharge, headaches, vision changes, acne, excess hair growth, hair loss, vaginal dryness, or pelvic pain.


• Diagnosis usually involves medical history, examination, pregnancy testing, hormone tests, and sometimes ultrasound or MRI.


• Treatment depends on the cause and may include lifestyle changes, hormone therapy, treatment of medical conditions, or surgery for selected structural problems.


• Untreated amenorrhea may affect fertility, bone health, uterine health, and emotional well-being.

What Is Amenorrhea?

Amenorrhea is usually divided into two main types: primary amenorrhea and secondary amenorrhea. Primary amenorrhea means that menstrual periods have not started by age 15. Medical assessment is also important if there is no breast development or other signs of puberty by age 13. Secondary amenorrhea means that periods have stopped after they had already begun. It is often defined as no period for three months in someone who previously had regular cycles, or six months in someone whose cycles were already irregular.

It is important to remember that not all absence of menstruation is abnormal. Periods naturally stop during pregnancy, may stop during breastfeeding, and stop permanently after menopause. Periods also do not occur before puberty. Outside these situations, missed or absent periods should be assessed, especially when they continue or occur with other symptoms.

Common Causes of Amenorrhea

The causes of amenorrhea vary depending on age, health, body weight, hormone balance, medications, and reproductive history. Pregnancy is the most common natural cause of missed periods in someone who could become pregnant. Breastfeeding can also delay the return of menstruation. Menopause causes periods to stop permanently.

Lifestyle-related causes are also common. Very low body weight, eating disorders, severe calorie restriction, excessive exercise, intense athletic training, and major stress can affect the hypothalamus, the part of the brain involved in controlling reproductive hormones. When the body senses that energy availability is too low, ovulation may stop and periods may disappear.

Hormonal and medical causes include polycystic ovary syndrome, thyroid disease, high prolactin levels, premature ovarian insufficiency, pituitary tumors, and disorders affecting the hypothalamus or pituitary gland. PCOS is a common cause of irregular or absent periods and may also cause acne, excess facial or body hair, weight gain, or difficulty becoming pregnant.

Structural causes can also prevent menstruation. These include scarring inside the uterus, known as Asherman syndrome, which may occur after uterine surgery, infection, or procedures involving the uterine lining. Some people may also have congenital differences in reproductive organ development that prevent menstrual bleeding from occurring normally.

Certain medications can contribute to amenorrhea. These may include some hormonal contraceptives, antipsychotic medicines, chemotherapy, and other treatments that affect hormone production or ovarian function.

Because amenorrhea can have many causes, the symptoms around the missed periods are often as important as the missed periods themselves.

Risk Factors for Amenorrhea

Some people have a higher risk of amenorrhea. These include those with eating disorders such as anorexia nervosa, people with very low body weight, and athletes who train intensely without enough calorie intake. Chronic stress, sudden weight loss, and restrictive diets may also increase risk.

A family history of delayed puberty, early menopause, irregular periods, or reproductive hormone conditions may also be relevant. Obesity can increase the risk of PCOS-related menstrual irregularity. Previous uterine surgery, procedures involving the uterine lining, chemotherapy, pelvic radiation, and certain long-term medications can also increase the risk depending on the situation.

How Amenorrhea Is Diagnosed

Diagnosis begins with a detailed medical history. A doctor may ask when periods started, when the last period occurred, whether cycles were regular before they stopped, whether pregnancy is possible, and whether there have been changes in weight, exercise, diet, stress, medications, or symptoms such as headaches, vision changes, nipple discharge, acne, excess hair growth, or pelvic pain.

A pregnancy test is usually one of the first steps in evaluating secondary amenorrhea. Other tests may include thyroid function tests, prolactin levels, ovarian hormone tests, and androgen levels when PCOS or androgen excess is suspected. A pelvic ultrasound may be used to look at the uterus and ovaries. MRI may be needed in selected cases, especially if pituitary disease is suspected.

No single test diagnoses every cause of amenorrhea. The aim is to identify why ovulation or menstruation has stopped, and whether the problem is related to pregnancy, hormones, the ovaries, the uterus, the brain, medications, or general health.

Complications of Untreated Amenorrhea

The complications of amenorrhea depend on the cause. If periods are absent because ovulation is not occurring, infertility or difficulty becoming pregnant may occur. In people with low estrogen levels, long-term amenorrhea may increase the risk of low bone density and osteoporosis. This is especially important in athletes, people with eating disorders, and those with premature ovarian insufficiency.

Some causes of amenorrhea may be linked with metabolic or cardiovascular risk, especially when conditions such as PCOS, obesity, insulin resistance, high blood pressure, or abnormal cholesterol are present. In people with long-term irregular or absent ovulation, the uterine lining may be exposed to unopposed estrogen, which can increase the risk of endometrial overgrowth. This is why persistent amenorrhea should not be ignored.

Amenorrhea can also affect mental and emotional well-being. Worry about fertility, body image, weight, hormonal symptoms, or an uncertain diagnosis can lead to stress, anxiety, or low mood.

Treatment of Amenorrhea

Treatment depends on the underlying cause. If pregnancy, breastfeeding, or menopause explains the absence of periods, treatment may not be needed unless there are other concerns.

When amenorrhea is linked to low body weight, restrictive eating, excessive exercise, or stress, treatment may involve improving nutrition, restoring healthy energy balance, reducing excessive exercise, and supporting mental health. In these cases, lifestyle correction is not cosmetic; it is part of restoring normal hormone function and protecting bone health.

If thyroid disease, high prolactin, PCOS, or another hormonal disorder is found, treatment targets that condition. Hormonal therapy may be used in some cases to regulate bleeding, protect the uterine lining, or replace missing hormones. Some people may use birth control pills or other hormone treatments, depending on the cause and fertility goals.

Surgery is needed only in selected cases, such as removal of uterine scar tissue, correction of structural blockage, or treatment of certain pituitary or reproductive tract problems.

When to See a Doctor

Medical advice is recommended if a girl has not started periods by age 15, if there are no signs of puberty by age 13, or if periods stop for three months or longer without a clear reason. A doctor should also be consulted sooner if amenorrhea occurs with headaches, vision changes, nipple discharge, pelvic pain, hot flashes, excessive hair growth, severe acne, sudden weight loss, or symptoms of an eating disorder.

This article is part of the 'Public Education Series' initiative by Exon Publications.

Disclaimer: This is for informational purposes only. For medical advice or diagnosis, consult a professional.

References

1. Gordon CM, Ackerman KE, Berga SL, Kaplan JR, Mastorakos G, Misra M, et al. Functional hypothalamic amenorrhea: an endocrine society clinical practice guideline. J Clin Endocrinol Metab. 2017;102(5):1413–1439. doi: https://doi.org/10.1210/jc.2017-00131


2. Practice Committee of the American Society for Reproductive Medicine. Current evaluation of amenorrhea. Fertil Steril. 2008;90(5 Suppl):S219–S225. doi: https://doi.org/10.1016/j.fertnstert.2008.08.012


3. Warren MP, Chua AT. Exercise-induced amenorrhea and bone health in the adolescent athlete. Ann N Y Acad Sci. 2008;1135:244–252. doi: https://doi.org/10.1196/annals.1429.025


4. Santoro N, Mechanick JI. Estrogen and menopause: an update. Endocr Pract. 2016;22(12):1547–1556. doi: https://doi.org/10.4158/EP161361.RA


5. Harlow SD, Gass M, Hall JE, et al. Executive summary of the stages of reproductive aging workshop (STRAW) + 10. Menopause. 2012;19(4):387–395. doi: https://doi.org/10.1097/gme.0b013e31824d8f40