hypothyroidism may get better or worse over time,
depending on its cause and your age.
Hypothyroidism in infants and children
rare, hypothyroidism can occur in
infants and children. If hypothyroidism is treated
within the first month of life, a child will grow and develop normally.
Untreated hypothyroidism in infants can cause brain damage, leading to
intellectual disability and
developmental delays. In the United States, all
children are tested for hypothyroidism at birth.
Intellectual disability usually does not occur if hypothyroidism develops
after age 3. But untreated childhood hypothyroidism typically delays physical
growth and sexual development, including the onset of
puberty. Children may gain weight yet have a slowed
Hypothyroidism in adults
Hypothyroidism caused by
Hashimoto's thyroiditis sometimes will disappear on
its own. More often, the disorder causes a gradual loss of thyroid function. Your symptoms may develop slowly and be so mild that you do not notice them for
years. But symptoms usually grow worse. And health problems may develop as the
If untreated, hypothyroidism may lead
- Myxedema, a condition that causes swelling of
tissues, increased fluid around the heart and lungs, slowed muscle reflexes,
and a slowed ability to think.
- Myxedema coma,
a rare, life-threatening condition. This can occur if you have had
hypothyroidism for many years that becomes markedly worse. It usually occurs
when older adults who have severe hypothyroidism become ill with another
condition, suffer from cold exposure, or take painkillers or sleeping pills.
Symptoms include mental deterioration, such as apathy, confusion, and
psychosis. You may lose consciousness (coma) and may
have an extremely low body temperature (hypothermia), slow heartbeat (fewer
than 60 beats per minute),
heart failure, and trouble
- Complications, such as:
- Increased levels of
triglycerides (increasing the risk of
coronary artery disease and
- Fluid around the heart (pericardial effusion).
- Sleep apnea, which causes you to stop breathing for 10
seconds or longer while sleeping.
- Forgetfulness and
People with mild (subclinical) hypothyroidism
have only slightly
abnormal thyroid blood test results and often do not have obvious symptoms or
health problems. Some people who have mild hypothyroidism regain normal thyroid
function. But about 1 out of 10 people who have mild hypothyroidism will go on to have hypothyroidism within 3 years.1
thyroid gland has been removed during surgery,
hypothyroidism will occur within a few weeks. If you have been treated with
radioactive iodine therapy, hypothyroidism may develop within a year. In these cases, thyroid function typically does not return,
and you will need to take thyroid hormone medicine from now on.
Hypothyroidism during and after pregnancy
who have hypothyroidism or mild hypothyroidism before they become pregnant may
have more severe hypothyroidism during their pregnancy. If not treated,
pregnant women who have hypothyroidism can develop
preeclampsia and have a premature delivery. Children
born to women who have untreated hypothyroidism during pregnancy are at risk for
having hypothyroidism at birth and low birth weight and may score lower on
intelligence tests than children of healthy mothers.2
After delivery, women may have a thyroid
disorder called postpartum thyroiditis. This condition occurs in about 5% of
women who do not have a history of thyroid disease.2
It is often mistaken for
Women who have postpartum
thyroiditis often develop hypothyroidism 3 to 6 months after delivery. The
hypothyroidism may last up to several months. It sometimes occurs after an initial episode of postpartum
thyroiditis that causes symptoms from too much thyroid hormone. Hypothyroidism may become permanent in
women with postpartum thyroiditis. Even if thyroid gland function returns to normal, postpartum
thyroiditis usually comes back during later pregnancies.