Hyperthyroidism During Pregnancy

Have an overactive thyroid? Here's everything you know to keep you and baby healthy throughout your pregnancy.
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ByAshley Roman, MD
Mar 2017
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What is hyperthyroidism during pregnancy?

Hyperthyroidism means your thyroid gland is overactive, putting too much of the thyroid hormone into your body. This can speed up your metabolism, affecting all your bodily processes.

What are the signs of hyperthyroidism?

Since everything’s going faster in your bod, you may be sweating more, have more frequent bowel movements, be  losing weight (or gaining it too slowly) or having trouble sleeping. You may also feel like your heart is racing or be irritable, nervous, anxious or weak. While you’re pregnant, it’s tough to tell if your thyroid is acting up or if the excessive sweating and vomiting are just from being pregnant. But a high heart rate (above 100 beats per minute) and weight loss are exclusive to mamas-to-be with hyperthyroidism.

Are there any tests for hyperthyroidism?

Yep. Your doc is likely to diagnose you through a physical exam and blood tests that measure your thyroid hormone levels.

How common is hyperthyroidism during pregnancy?

Not very. Less than 1 percent of pregnant women are affected by hyperthyroidism. Most of those are due to Graves’ disease.

How did I get hyperthyroidism?

You may have inherited it — hyperthyroidism seems to run in families.

How will my hyperthyroidism affect my baby?

Don’t worry — just because you have hyperthyroidism doesn’t mean you’ll pass it on to baby. In fact, less than 2 percent of babies born to mamas with Graves’ disease suffer from hyperthyroidism themselves. Still, baby will need to be tested right after birth, just in case. Signs of hyperthyroidism in baby include an increased fetal heart rate, enlargement of the fetal thyroid gland and poor growth of the fetus.

What’s the best way to treat hyperthyroidism during pregnancy?

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You can — and should — take your hyperthyroid meds during pregnancy. Medicines like propylthiouracil or methimazole are not only safe to take during pregnancy, they also provide excellent control of the disease, reducing your risk of pregnancy complications.

But it’s not just business as usual. You’ll need to see your health care provider for monthly blood tests to check your thyroid function.

What can I do to prevent hyperthyroidism?

Sorry, but there’s nothing you can do since the cause is unknown.

*What do other pregnant moms do when they have hyperthyroidism?
“I’ve got a moderate case of hyperthyroidism and I’m six weeks pregnant. My doctors want me to start treatment right away and think the risks of going untreated outweigh the medication risks. It’s tough getting comfortable with starting a Class D medication, no matter how small the dose.”

“In my opinion, there are more risks by not taking thyroid meds than you have by actually taking them.”

Are there any other resources for hyperthyroidism during pregnancy?

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