Hypothyroidism during Pregnancy

Hypothyroidism is a condition that develops if your thyroid has low activity. The thyroid is a small, butterfly-shaped gland in your neck. It is located in front of your windpipe. It makes hormones that play an important role in regulating your breathing, heart rate, menstrual cycle, body temperature, and other bodily functions. If you have hypothyroidism, your thyroid gland does not produce enough thyroid hormones.

When you are pregnant, your body uses more thyroid hormones. This can cause mild hypothyroidism to get worse.

How does this affect me?

Hypothyroidism during pregnancy can cause you to have:

• Fatigue.
• Abnormal weight gain. For women of normal weight, it is common to gain about 1 pound per week during pregnancy.
• Difficulty having a bowel movement (constipation).
• Feeling cold more often than others do.
• Muscle aches.
• Pregnancy complications, such as:
  • High blood pressure that develops after the 20th week of pregnancy (preeclampsia).
  • Pregnancy loss (miscarriage).
  • Preterm birth.
  • Placenta problems.

How does this affect my baby?

Hypothyroidism can also affect your baby. Babies need thyroid hormone from their mothers for normal growth and brain development. Babies born to mothers with hypothyroidism during pregnancy may:

• Be born prematurely.
• Have low birth weight.
• Have mental delays.
• May develop hypothyroidism. This is rare.

What can I do to lower my risk?

Some women with hypothyroidism need extra iodine during pregnancy. Your health care provider may recommend that you:

• Eat foods with iodine, such as:
  • Iodized salt.
  • Pasteurized eggs and dairy products.
  • Low-mercury seafood.
• Take a prenatal vitamin that contains iodine.
• Take iodine supplements.

How is this treated?

Treatment may include:

• Monitoring. If you have mild hypothyroidism, your health care provider will monitor your thyroid hormone levels closely to watch for any changes.
• Medicines. Your health care provider may prescribe medicine to control your thyroid hormone levels.

Follow these instructions at home:

• Take over-the-counter and prescription medicines only as told by your health care provider.
  • Check with your health care provider before taking any hypothyroid medicines that were prescribed before you became pregnant. Many are safe, but some treatments for hypothyroidism may have to be stopped during pregnancy.
• You may be asked to perform kick counts to monitor your baby’s movements. If your baby moves fewer than 10 times in 2 hours during a period when the baby is usually active (typically in the evening), you should see your health care provider right away.
• Take a prenatal vitamin as told by your health care provider.
• Keep all follow-up visits. This is important.

Contact a health care provider if you:

• Have new symptoms or your symptoms get worse.
• Gain more than 5 lb (2.3 kg) in 1 week.
• Have a lump in your neck.
• Have a scratchy throat or difficulty speaking that lasts longer than a month and is not related to a cold.
• Have a hard time swallowing.

Get help right away if:

• Your baby is less active than normal.
• Your baby stops moving completely.
• You develop muscle cramps.
• You have pain in your abdomen.
• You have heavy bleeding.
• You develop a fever or chills.
• You have a very bad headache or vision problems.
• You develop swelling in your legs and ankles.

Summary

• Hypothyroidism is a condition that develops if your thyroid has low activity.
• Hypothyroidism during pregnancy can lead to complications for both you and your baby.
• Take medicines, vitamins, and supplements as told by your health care provider during your pregnancy to control your condition.
• Keep regular prenatal appointments so your health care provider can closely monitor your condition during pregnancy.