What is Amenorrhoea?
Amenorrhoea is the absence of periods (menstruation). Usually, but not always, it also means no eggs are produced (anovulation). In many cases, as in girls before puberty, or during pregnancy, breastfeeding or the menopause, this is normal and is called physiological amenorrhoea.
An associated condition known as Oligomenorrhoea refers to infrequent periods, usually every three to six months which may be irregular and long.
Primary amenorrhoea is the failure to establish menstruation. It is regarded as abnormal if a girl has not started sexual physical development and menstruation by the age of 14, or if a girl with normal sexual physical characteristics has not started menstruation by the age of 16. Primary amenorrhoea affects only about 3 girls per 1000.
Secondary amenorrhoea is defined as the absence of menstruation for six consecutive months in a woman who previously had regular periods. Secondary amenorrhoea implies a gynaecological disorder or a general cause or disease.
Secondary amenorrhoea affects about 3% of girls. Up to 50% of competitive long-distance runners (running 80 miles per week) and up to 44% of ballet dancers have amenorrhoea.
What is the cause of amenorrhoea?
There are many possible causes. They include:
- Excessive exercise. It is particularly common in athletes involved in endurance events.
- Being severely underweight, as a result of an eating disorder or illness. Regular menstruation is unlikely if the body mass index (weight in Kg divided by the height in metres squared) is less than 19 (the normal range is 20 to 25).
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- Severe stress or emotional disturbance
- A disorder of the ovary that prevents eggs from being produced
- Various medical drugs
- A reaction to stopping the contraceptive pill. About one woman in 100 will have amenorrhoea for three to six months after stopping use of the pill. This is commonest in women who have taken the pill continuously without a regular pill-free interval.
- Polycystic ovary syndrome: a condition associated with multiple cysts in the ovaries, which features menstrual disturbances or absence of menstruation, sterility, obesity and a male distribution of body hair from hormonal disturbances. Severe long-term illness, or under- or over-activity of the thyroid gland.
- Abnormal operation of the hormones controlling ovulation and menstruation produced by the hypothalamus gland (which in turn controls the pituitary gland).
Rare causes of amenorrhoea include:
- Absence at birth of the vagina, or womb, or both
- A hymen that completely closes off the vagina
There are rare cases where the true sex of a child is confused because of poorly developed genital organs at birth.
The Diagnosis of amenorrhoea?
This will depend on the nature of the underlying cause; but depending on age and history, a pregnancy test is often the first step.
A full history is taken, covering such things as the family history, work and activity history, sexual history, emotional upsets, changes in body weight and previous medical history.
Otherwise, diagnosis may involve a full gynaecological examination and various tests. These tests may include blood tests to determine the levels of the various hormones. Chromosome analysis will be necessary if there is doubt as to the patients sex.
Ultrasound, computerised tomography (CT scan) or MRI scanning will show any genital.
The treatment of amenorrhoea?
Treatment will depend on the underlying cause.
Many cases can be cured by hormone replacement therapy (HRT). Amenorrhoea associated with exercise will respond to modification of the exercise programme along with attention to diet and weight.
Weight-related amenorrhoea should be managed by weight gain and may require psychiatric assistance if there is a suspected eating disorder.
In some cases where the genitals have not developed properly, surgery can help.
Polycystic ovary syndrome may respond to a reduction in weight, and recently there has been interest in the use of insulin-sensitising agents such as metformin.
Thyroid underactivity can be treated with thyroid hormone (thyroxine).
Correcting a complete hymen, requires a simple surgical operation.
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