Family doctor


Women's Health

AMENORRHOEA - a patient's guide


Lack of menstrual periods can be a symptom of an underlying problem. This article looks at some of the causes and what treatment is available.



  • Periods usually start about age 12 and occur every 24-35 days. It can take up to two years for periods to settle into a regular pattern.
  • Primary amenorrhoea means no periods by the age of 16. Secondary amenorrhoea means no periods for more than six months in a woman who was previously having normal periods.
  • Amenorrhoea is a symptom of an underlying condition. The most common causes are pregnancy, breastfeeding, menopause, contraception, stress and low body weight.
  • 10-20% of women with infertility problems have amenorrhoea.
  • Treatment involves finding the cause and restoring normal periods.


Secondary amenorrhoea - This is much more common and has several causes:

  • Pregnancy and breastfeeding (lactation).
  • Menopause.
  • Contraceptives - Some women on the oral contraceptive pill ("The Pill" and "The Mini-Pill"), and many women on Depo Provera injections, experience no periods. This can cause some anxiety but providing that you are well, and you have been tested to make sure you are not pregnant, you can be reassured that this may be normal for you.
  • Stress / low body weight / excessive exercise - The hormonal system can be affected by these states. It is not uncommon to have no periods while changing jobs or schools, travelling, or when you are under emotional stress. Women who are below their ideal weight can stop ovulating and therefore experience no periods. This weight is different for every woman although a "normal" body weight is defined as having a BMI (Body Mass Index) of 20-25, calculated as weight (kg)/height (m)2. Sufferers of anorexia nervosa often stop having periods for this reason. Excessive exercise, marijuana use and chronic illness can also cause amenorrhoea.
  • Polycystic ovaries (see article on this). This condition will often interfere with regular ovulation. Associated symptoms of acne and excessive hair may be noted due to a hormonal imbalance.
  • Hormonal disorders - Rarely, benign (non cancerous) tumors can occur in the pituitary gland. This leads to an excess of the hormone Prolactin that can stop periods, and cause a milky discharge from the nipples. Disorders of other glands such as the thyroid, adrenal and the ovaries can also cause periods to stop but these are rare.
  • Medical therapies - Occasionally periods can stop after pelvic surgery or chemotherapy. Prescription medicines such as Haloperidol can also cause amenorrhoea.

Primary Amenorrhoea:

This is much less common and can be due to all the causes of secondary amenorrhoea as well as other rare problems. These include abnormalities of the uterus and vagina (e.g. imperforate hymen), chromosomal defects, and rare problems in the hormonal system. If you have not had a period by age 14 and you are slow in reaching puberty, you should seek medical advice. If you have the normal physical features of puberty and you are healthy, you can wait until age 16 before seeking help.

What to watch out for:

In addition to the absence of periods, you may notice other things about your body suggestive of an underlying cause. A low body weight, unusual hair growth, acne, milky discharge from the nipples, prolonged stress, difficulty getting pregnant and a delay in puberty are all clues that will help the doctor make a diagnosis.

Women entering menopause may notice hot flushes, fatigue, muscle aches, poor concentration and sometimes mood swings.

What needs to be done?

You will need help from your family doctor. You will be asked questions about your health and you will need to have a physical examination. Pregnancy is usually ruled out with a simple urine test. Often blood tests will need to be done and you may need an ultrasound scan of your pelvis.

Treatment is aimed at correcting the underlying cause. The aim is to restore normal periods. If your amenorrhoea is due to stress or low weight, changes to your lifestyle will need to be explored. If periods do not resume, hormone therapy such as the combined oral contraceptive or hormone replacement therapy may be needed. This ensures an adequate supply of oestrogen, an important hormone that protects against weak bones (osteoporosis).

It must be remembered that an absence of periods does not automatically mean infertility. You could spontaneously ovulate at any time so it is important to use some form of contraception if you want to avoid pregnancy.

You may be referred to a specialist, especially if you are planning to get pregnant or if your doctor suspects an important underlying cause. Cases of primary amenorrhoea should usually be referred to a specialist.

See also:

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