Hyperthyroidism in Pregnancy

What is hyperthyroidism?

Hyperthyroidism (hi-per-THI-roi-dizm) is a condition where the thyroid gland makes too much of the thyroid hormone. The thyroid gland is a butterfly-shaped organ that makes hormones, and is located in the front part of your neck. Hormones are special chemicals that act as messengers to help control how your body works. The thyroid gland makes the thyroid hormone that help control your body's functions, including body temperature, heart rate, and growth. The thyroid hormone also controls how fast your body changes and uses food for your energy needs. It also affects the way your body uses vitamins, proteins, carbohydrates, fats, and water. These functions in turn affect how the body gains or loses weight.

What causes hyperthyroidism?

The following may damage your thyroid gland and cause hyperthyroidism:

Autoimmune disease:

Grave's disease is an autoimmune disease that damages the thyroid and increases thyroid hormone production. The immune system is your body's defense system against infections and diseases. An autoimmune disease happens when immune cells produce antibodies that attack your own body's cells. Your body's immune cells attack the thyroid gland and affect its ability to work properly.

Diet:

Having too much or too little iodine in your diet and taking medicines with iodine may cause hyperthyroidism. Iodine is an important mineral used by the thyroid gland to function normally and make the thyroid hormone.

Infections:

Infection near the thyroid gland may spread and cause damage.

Nodules:

Nodules, also called lumps, are round masses that may grow in your thyroid gland and affect its function. Some nodules may be related to cancer (tumor), and may grow and spread to other areas.

What happens with hyperthyroidism during pregnancy?

During pregnancy, there is an increase of a certain hormone in the body that may stimulate the thyroid gland. As the thyroid gland is stimulated, it makes more of the thyroid hormone which causes the problems during pregnancy. Pregnancy also makes your body, including the thyroid gland, work harder for both you and your growing baby. The health of women who get pregnant while having this condition may become worse. A past history of hyperthyroidism may increase your chance of having it again during pregnancy. Having this condition while you are pregnant may put you at risk for any of the following:

Abortion (miscarriage).

Babies with low birth weight.

Heart failure.

Pre-eclampsia, which is a condition having hypertension (increased blood pressure), low platelet count, protein in the urine, and problems thinking.

Preterm labor or having the baby delivered before the proper time.

Stillbirths or babies dying inside the womb.

What are the signs and symptoms of hyperthyroidism during pregnancy?

During pregnancy many changes happen to your body. The signs and symptoms of hyperthyroidism may start slowly and you may not notice any change. You may only have a feeling that something is wrong when the signs and symptoms become worse. You may have any of the following:

Eyes bulging out more than the usual.

Feeling nervous, tense, restless, cannot sleep well, and cannot stay still for long periods.

Feeling hungry even if you are eating most of the time.

Heart beating very fast even when you are at rest, tremors, and getting tired and sweaty easily.

Increased blood pressure, with headache, nausea (feeling like throwing up), and blurring of vision.

Lump in the front of your neck which may be painful.

What is a thyroid storm?

This is a condition when hyperthyroidism gets very bad. Your temperature may go very high, your heart may beat very fast, and you may have problems thinking. You may have increased sweating, vomiting (throwing up), or diarrhea (loose bowel movements). You may have seizures (convulsions), or go into a coma and die if you do not get medical care quickly. Your growing baby may also be affected, and may have birth defects or die. Thyroid storm may happen when a patient with hyperthyroidism gets a bad infection or stops taking thyroid medicines. It may also be caused by bad injuries, burns, and taking certain medicines.

How is hyperthyroidism during pregnancy diagnosed?

Your caregiver may do a complete medical history and physical examination. He may also ask about the health of your family. He may need to have the baby in your womb examined to make sure he is healthy. You may have any of the following:

Biopsy:

This is a procedure where a very small piece of your thyroid gland is taken and sent to a lab for tests. Your caregiver uses this to check for other problems with your thyroid gland. A small needle may be used to get a sample of your thyroid gland. Your caregiver may use numbing medicine so that you may not feel any pain during the procedure.

Blood tests:

You or your baby may need blood taken for tests. The blood can be taken from a blood vessel in your hand, arm, or the bend in your elbow. Your caregiver may also get blood from your baby from the blood vessels in your womb. It may tell your caregiver how high your thyroid hormone levels are. This information may also be used to see how well your thyroid is responding to the treatments. The other blood tests may give your caregivers more information about your and your baby's health. You may need to have blood drawn more than once.

Fetal ultrasound:

This test uses sound waves to show pictures of your baby inside your uterus (womb). These pictures are seen on a TV-like screen. Your caregiver may use this to check for problems that may happen to your baby.

How is hyperthyroidism during pregnancy treated?

Treatment for hyperthyroidism during pregnancy will depend on your health, age, and the size of your thyroid gland. You may have any of the following:

Medicines:

Antithyroid medicines:

These medicines act on the thyroid and stop it from making too much thyroid hormone. They may also decrease and prevent the signs and symptoms of hyperthyroidism. These may be used during your pregnancy.

Others:

Medicines to treat very fast heartbeats, nervousness, too much sweating, and trembling may also be given. These may also be used during your pregnancy.

Surgery:

Some pregnant women with hyperthyroidism may need surgery to remove all or part of the thyroid gland. By reducing the size of your thyroid gland, the amount of thyroid hormone produced will also decrease. Your caregiver may do surgery during your pregnancy if he feels that you and your baby will be OK having surgery. You may be given antithyroid medicine for several months before surgery. This medicine will decrease your symptoms and make the thyroid gland smaller before surgery.