Development of male characteristics in a female due to a hormonal imbalance

  • May be present at birth but usually develops later in life
  • In some cases, the cause is inherited
  • Lifestyle is not a significant factor

Normally, low levels of male sex hormones are present in females and are produced by the adrenal glands and the ovaries. However, if the production of these hormones increases significantly, various male characteristics begin to develop, a condition called virilization.

Virilization most commonly occurs in adulthood, causing symptoms such as deepening of the voice, excessive hair growth on the face and body known as hirsutism, and thinning of the hair on the temples and crown. These symptoms often cause psychological distress. Rarely, the condition is present at birth. If present at birth, virilization is usually due to a genetic disorder that causes abnormal hormone levels (see Congenital adrenal hyperplasia).

Excessive facial hair

This young woman has excessive facial hair (hirsutism), a common symptom of virilization, a condition caused by the excess production of male sex hormones.

What are the causes?

When virilization develops later in life, the possible causes include abnormalities of the ovaries, such as certain types of ovarian cysts, cancer of the ovary, and polycystic ovary syndrome. Hormone levels can also be increased by adrenal tumours and the use of certain male hormone supplements by athletes.

What are the symptoms?

In the rare cases when virilization is present at birth, the most obvious feature is ambiguous-looking genitals. In other cases, symptoms appear gradually as male sex hormone levels rise. They include:

  • Excessive growth of hair on the face and body.

  • Less regular or absent menstruation (see Amenorrhoea).

  • Reduction in breast size or in rare cases failure of the breasts to develop.

  • Enlargement of the clitoris.

  • Irreversible enlargement of the larynx (Adam’s apple), causing the voice to become deeper.

  • Thinning of the hair around the temples and crown (see Male-pattern baldness).

The hormonal imbalance may lead to increased muscular development, producing a male body shape.

What might be done?

Your doctor will examine you and may arrange tests to determine the cause of your symptoms. These tests include blood tests to measure hormone levels, MRI or CT scanning to look for an adrenal tumour, and ultrasound scanning to check the ovaries. Treatment of the cause, such as removal of a tumour, should reverse some of the changes. If no cause is found, combined oral contraceptives may be given to suppress hormone production by the ovaries and reduce male sex hormone levels. You may be given advice on how to manage excessive hair, perhaps by using electrolysis or waxing. Counselling is often helpful.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

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