An underactive thyroid gland (hypothyroidism) is where your thyroid gland doesn't produce enough hormones.

Common signs of an underactive thyroid are tiredness, weight gain and feeling depressed.

An underactive thyroid can often be successfullytreated by taking daily hormone tablets to replace the hormonesyour thyroid isn't making.

There's no way of preventing an underactive thyroid. Most cases are caused either by the immune system attacking the thyroid gland and damaging it,orby damage to the thyroid that occurs during some treatments for an Thyroid, overactive or thyroid cancer .

Who's affected

Both men and women can have an underactive thyroid, althoughit's more commonin women. In the UK, it affects 15 in every 1,000 women and1 in 1,000 men. Children can also develop an underactive thyroid.

Around 1 in 3,500-4,000 babiesare born with anunderactive thyroid (congenital hypothyroidism).All babies born in the UK are screened for congenital hypothyroidismusing a blood spot test when the baby is about five days old.

Treating an underactive thyroid

Treatment for an underactive thyroid involves taking dailyhormone replacement tablets, called levothyroxine,to raise yourthyroxine levels. You'll usually need treatment for the rest of your life. However, with proper treatment, you should be able to lead a normal, healthy life.

If an underactive thyroid isn't treated, it can lead to complications, including heart disease , goitre , pregnancy problems and a life-threatening condition called myxoedema coma (although this is very rare).

and the complications of an underactive thyroid .

Content supplied by the NHS Website

Medically Reviewed by a doctor on 29 Nov 2016