An underactive thyroid is where your thyroid gland does not produce enough hormones. It is also known as hypothyroidism.
Both men and women can have an underactive thyroid. But it's more common in women.
Children can also develop an underactive thyroid. Some babies are born with it. If it is found at birth, it is called congenital hypothyroidism.
All babies born in Ireland are screened for congenital hypothyroidism using a blood spot test. This is done when the baby is around 5 days old.
Common symptoms of an underactive thyroid
Common signs of an underactive thyroid are:
- tiredness
- weight gain
- feeling depressed
Many symptoms are the same as those of other conditions. Some people can confuse it for something else.
Symptoms usually develop over time. You may not realise you have a medical problem for years.
Other symptoms include:
- being sensitive to cold
- constipation
- slow movements and thoughts
- muscle aches and weakness
- muscle cramps
- dry and scaly skin
- hair and nails that break easily
- loss of libido (sex drive)
- pain, numbness and a tingling sensation in the hand and fingers - this is known as carpal tunnel syndrome
- irregular periods or heavy periods
If you have any of these symptoms, see your GP. Ask them to test for an underactive thyroid.
Getting tested for an underactive thyroid
If you are elderly
Elderly people with an underactive thyroid may develop memory problems and depression.
If you are a child
Children may grow and develop slower. Teenagers may start puberty early.
Symptoms of an untreated underactive thyroid
If an underactive thyroid is not treated, more symptoms can develop. But most people get treatment before serious symptoms appear.
Later symptoms include:
- a low-pitched and hoarse voice
- a puffy-looking face
- thinned or partly missing eyebrows
- a slow heart rate
- hearing loss
- anaemia
The thyroid gland
The thyroid gland is a small butterfly-shaped gland in the neck, just in front of the windpipe (trachea).
One of its main functions is to produce hormones that help regulate the body's metabolism. These hormones are called triiodothyronine (T3) and thyroxine (T4).
Many of the body's functions slow down when the thyroid does not produce enough of these hormones.
Content supplied by the NHS and adapted for Ireland by the HSE
