Hypothyroidism (Underactive Thyroid)
What Causes Hypothyroidism? continued...
. The reason isn’t clear, but sometimes, inflammation of the thyroid occurs after pregnancy. This is called postpartum thyroiditis. Women with this condition usually have a severe increase in thyroid hormone levels followed by a sharp drop in thyroid hormone production. Most women with postpartum thyroiditis will regain their normal thyroid function.
Problems with the thyroid at birth. Some babies may be born with a thyroid gland that did not develop correctly or does not work properly. This type of hypothyroidism is called congenital hypothyroidism. Most hospitals in the U.S. screen babies at birth for this disease.
Pituitary gland damage or disorder. Rarely, a problem with the pituitary gland can interfere with the production of thyroid hormone. The pituitary gland makes a hormone, called thyroid-stimulating hormone (TSH), which tells your thyroid how much hormone it should make and release.
Disorder of the hypothalamus. An extremely rare form of hypothyroidism can occur if the hypothalamus in the brain does not produce enough of a hormone called TRH. TRH affects the release of TSH from the pituitary gland.
Primary hypothyroidism is caused by a problem with the thyroid gland itself.
Secondary hypothyroidism occurs when another problem interferes with the thyroid's ability to produce hormones. For example, the pituitary gland and hypothalamus produce hormones that trigger the release of thyroid hormone. A problem with one of these glands can make your thyroid underactive.
Sometimes, an underactive thyroid that results from a problem with the hypothalamus is called tertiary hypothyroidism.
Who Is at Risk for Hypothyroidism?
Women, particularly older women, are more likely to develop hypothyroidism than men. You are also more likely to develop hypothyroidism if you have a close family member with an autoimmune disease. Other risk factors include:
Symptoms of Hypothyroidism
Symptoms of hypothyroidism may be vague and can often mimic other conditions. They may include:
- Changes in the menstrual cycle
- Dry hair and hair loss
- Dry skin
- Greater sensitivity to cold
- Slow heart rate
- Swelling of the thyroid gland (goiter)
- Unexplained weight gain or difficulty losing weight
- Carpal tunnel syndrome