Your Thyroid Levels During Pregnancy

Woman holding her pregnant belly

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Your thyroid is a butterfly-shaped gland in your neck. It is a part of your endocrine system and it helps regulate many hormones. It is fairly common to test for thyroid-related issues in most prenatal care settings. Your doctor or midwife may check your thyroid-stimulating hormone (TSH), this hormone tells us how hard your thyroid is working. When this number is over the expected range, or high, you are said to be hypothyroid.

When the number is lower than the normal range, your thyroid levels are high and you are said to be hyperthyroid. Other numbers that your practitioner will look at on the T3 and T4 levels. These are screenings, you may require more tests or retest due to the demands of pregnancy on your thyroid. 

Thyroid Levels in Pregnancy

If your practitioner does not routinely check for thyroid disease in pregnancy, ask to be screened.

1. Everyone can have thyroid problems. Even if you’ve never had thyroid issues prior to pregnancy, you should have your thyroid levels checked in early pregnancy and again in early postpartum. These are very likely times when you may experience difficulties with your thyroid for a variety of reasons.

2. Low thyroid levels can cause intellectual disability and other problems. Your thyroid hormones are necessary for a healthy baby. It is important that you have the right amount of hormone in your system to ensure a healthy baby.

3. Be checked early in pregnancy if you already take thyroid replacements. Even early on in pregnancy, your thyroid hormone needs can change. You may need to increase or adjust the amount of medication you are taking. You may need to be rechecked frequently throughout your pregnancy to ensure a safe and healthy pregnancy.

4. Don’t stop taking your thyroid hormones. If you become pregnant while taking thyroid replacement medications, do not stop taking your medications. Thyroid replacement hormones are a pregnancy Category A drug, meaning they are among the safest drugs available during pregnancy. Talk to your doctor before changing any of your medications.

5. Don't Panic. It is possible to have a safe, uneventful pregnancy, birth, postpartum and breastfeeding experience while experiencing thyroid difficulties. Keeping an eye on thyroid levels and adjusting your medications as necessary are the only treatments that you should need in pregnancy and beyond. If you keep a good eye on this, you shouldn’t have many worries about your pregnancy or birth. It is also important to note that breastfeeding is possible and highly encouraged, even if you have thyroid issues and take medications.

If your screening reveals that you are experiencing problems with your thyroid, you may have a lot of questions. Be sure to ask your doctor or midwife for time to discuss your concerns. You may even want to ask about an appointment prior to your regularly scheduled meeting if it's early in pregnancy and your appointments are a month apart. You may also discuss the potential need to see an endocrinologist.

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  • The American Thyroid Association Taskforce on Thyroid Disease During Pregnancy and Postpartum, Stagnaro-Green A, Abalovich M, et al. Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and Postpartum. Thyroid. 2011;21(10):1081-1125. doi: 10.1089/thy.2011.0087.

By Robin Elise Weiss, PhD, MPH
Robin Elise Weiss, PhD, MPH is a professor, author, childbirth and postpartum educator, certified doula, and lactation counselor.