What is Graves disease?

Graves disease is a condition where the thyroid gland makes too much thyroid hormone. This is called hyperthyroidism or overactive thyroid. Graves disease is the most common cause of hyperthyroidism during pregnancy. Having too much thyroid hormone speeds up the way the body uses energy and controls growth. 

What causes Graves disease in pregnancy?

A healthy thyroid gland works normally in pregnancy. Fewer than 1 in 100 women has an overactive thyroid in pregnancy. Graves disease is a problem with the body's immune system. Researchers believe it is caused by an antibody that triggers the thyroid gland to make too much thyroid hormone.

Who is at risk for Graves disease in pregnancy?

The disease is most common in young to middle-aged women. It tends to run in families.

What are the symptoms of Graves disease?

• Goiter (too-large thyroid gland bulging in the front of neck)

• Bulging eyes

• Thickened skin over the shin

• Nervousness

• Irritability

• Sweating more than normal 

• Thinning of the skin

• Fine, brittle hair

• Weak muscles, especially in the upper arms and thighs

• Shaky hands

• Fast heartbeat

• High blood pressure

• Increased bowel movements

• Weight loss

• Sleeping problems

• Eye sensitivity to light

• Staring

• Confusion

• Goiter in the unborn baby

The symptoms of hyperthyroidism may look like other health conditions. Always see your healthcare provider for a diagnosis.

How is Graves disease in pregnancy diagnosed?

The healthcare provider will ask about your health history. He or she will also do a physical exam, and ask about symptoms. Graves disease is diagnosed with a blood test to measure the amount of thyroid hormone.

How is Graves disease in pregnancy treated?

The goal of treatment is to keep the thyroid hormone levels normal. Treatment may include:

• Frequent checks of thyroid levels throughout pregnancy

• Anti-thyroid medicines, if the treatment is more important than the risk. Some medicines cross the placenta and may not be safe for the baby.   

• Surgery to remove part of the thyroid (the part that is overactive)

Radioactive iodine damages the overactive thyroid cells. But this treatment is not safe in pregnancy.

If you have Graves disease, you can take steps to have a healthy pregnancy. Get early prenatal care and work with your healthcare provider to manage the disease.

What are possible complications of Graves disease in pregnancy?

Graves disease usually gets worse in the first half of pregnancy. It gets better in the second half, and then gets worse again after delivery.

It is important to keep your thyroid levels normal. Hyperthyroidism that is out of control may lead to preterm birth. This is birth before 37 weeks of pregnancy. It can also lead to low birth weight of the baby. The most common complication is preeclampsia. This is a kind of high blood pressure of pregnancy.

Some pregnant women have a severe life-threatening form of hyperthyroidism called thyroid storm. This is a condition in which there are very high levels of thyroid hormone. It can cause high fever, dehydration, diarrhea, fast and irregular heartbeat, shock, and even death, if not treated.

Medicines to treat hyperthyroidism may harm your developing baby and newborn. Birth defects are more likely with some anti-thyroid medicines. Anti-thyroid medicine may also cause low levels of thyroid (hypothyroidism) in the developing baby and newborn. A condition called neonatal hyperthyroidism may happen in a few newborns. It is usually short-term and does not cause problems for the baby, but careful monitoring is important.

Key points about Graves disease in pregnancy

• Graves disease is a condition where the thyroid gland makes too much thyroid hormone. It is the most common cause of hyperthyroidism during pregnancy.

• The disease is most common in young to middle-aged women. It tends to run in families.

• The goal of treatment is to keep the levels of thyroid hormone normal.

• The most common complication is preeclampsia, a kind of high blood pressure of pregnancy.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

• Know the reason for your visit and what you want to happen.

• Before your visit, write down questions you want answered.

• Bring someone with you to help you ask questions and remember what your provider tells you.

• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

• Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.

• Ask if your condition can be treated in other ways.

• Know why a test or procedure is recommended and what the results could mean.

• Know what to expect if you do not take the medicine or have the test or procedure.

• If you have a follow-up appointment, write down the date, time, and purpose for that visit.

• Know how you can contact your provider if you have questions.