Hypothyroidism is common, especially among women, and many people have the condition throughout their lives. Hypothyroidism means that the thyroid gland produces too little thyroid hormone. The body slows down and metabolism becomes low.

The most common cause of hypothyroidism is that the body's own immune system attacks the thyroid gland and causes inflammation that destroys thyroid tissue. There are also other causes, such as disease of the thyroid or pituitary gland, iodine deficiency, or previous surgery or treatment for goiter.

Common symptoms of hypothyroidism can include

• Fatigue and reduced energy
• Feeling cold
• Depression
• Difficulty concentrating
• Weight gain and difficulty losing weight
• Constipation
• Dry skin and hair
• Poorer memory
• Facial swelling
• Deeper voice
• Bradycardia (abnormally low heart rate)
• Pale skin
• Headache
• Lack of sex drive

In women, menstrual disorders can also be a symptom of hypothyroidism. Sometimes the thyroid gland may be enlarged in hypothyroidism, known as goiter. Untreated hypothyroidism that continues for a long time can lead to serious medical conditions.

Investigation and treatment

The TSH level in the blood is the most sensitive indicator of thyroid disorders. High levels of the hormone TSH in the blood indicate an underactive thyroid, known as hypothyroidism. By measuring TSH in the blood, a possible thyroid disorder can be detected early and serious health complications may be avoided through further medical evaluation and treatment. As a rule, blood samples need to be taken on a few different occasions for a doctor to confirm the diagnosis.

Once the diagnosis is confirmed, you receive treatment with medication that replaces the hormone the body is lacking. It can take several months or up to a year before hormone levels have normalized and been adjusted correctly for the individual. You need to see a doctor regularly to check your values and possibly adjust your medication as the body and metabolism change.