Underactivity, developmental failure, or absence of the ovaries, leading to low levels of female sex hormones
- Sometimes due to a chromosomal abnormality
- Age and lifestyle as risk factors depend on the cause
Female sex hormones control sexual development and the menstrual cycle. Underactivity of the ovaries, known as hypogonadism, leads to low levels of these hormones in the body. A decline in hormone levels occurs naturally during the menopause, but at other times it may indicate an underlying disorder. Hypogonadism may cause distressing symptoms but is often treatable.
What are the types?
There are two types of hypogonadism: primary and secondary. Either type can occur at any age. Primary hypogonadism is often caused by a disorder or failure of the ovaries, which may result from a chromosomal abnormality such as Turner’s syndrome. It may also be caused by the surgical removal of the ovaries. In most cases, primary hypogonadism occurs as a natural consequence of the menopause.
Secondary hypogonadism is caused by an abnormality of the pituitary gland or of the hypothalamus (a part of the brain) that leads to underproduction of the hormones that stimulate the ovaries to function. This abnormality may be due to a disorder such as a pituitary tumour or, rarely, to damage to the pituitary gland or the hypothalamus as a result of a head injury or an infection such as viral encephalitis. Sometimes, it results from excessive exercise or sudden weight loss.
What are the symptoms?
Symptoms depend on the age at which hypogonadism develops and the amount of sex hormones produced. If the onset occurs before puberty, the condition causes abnormal puberty. If it is after puberty, symptoms may include:
What might be done?
Your doctor may arrange for you to have blood tests to measure your hormone levels. You may also have CT scanning of the brain to look for a pituitary abnormality or ultrasound scanning of the ovaries.
The treatment depends on the cause. For example, a pituitary tumour may be removed by surgery. If the condition is due to weight loss, gaining weight may help. In some cases, hormone treatment may be prescribed to induce puberty. Women who go through premature menopause (before age 40) may be advised to have hormone replacement therapy until age 50 to relieve symptoms and give protection from diseases associated with low levels of sex hormones, such as osteoporosis. For women under 50, the health risks of hormone replacement therapy are thought to be less than normal.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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