How Thyroid Disease can Affect Your Pregnancy

Your thyroid gland is a butterfly-shaped gland that is located in the front of your neck. Its job is to produce thyroid hormones that help regulate your metabolism, and these hormones affect many organs in your body. Having too much or too little thyroid hormone can cause problems for your pregnancy, so knowing the signs of possible problems can be helpful in women who are trying to conceive or are already pregnant.


Hyperthyroidism is when the thyroid gland produces an excessive amount of thyroid hormone. Symptoms include a high heart rate, jitteriness, nervousness, unintentional weight loss, heat intolerance, sweating, palpitations, insomnia, and high blood pressure, to name a few. If you think some of this sounds like normal pregnancy symptoms, you’re right. That’s why knowing what a true thyroid problem is can sometimes be tricky. In general, the symptoms of hyperthyroidism are a lot more dramatic than the occasional pregnancy-related hot flash. A woman might also have a lump on her neck known as a goiter, which is when the thyroid gland becomes enlarged.

This can affect the developing baby as well. If left untreated, hyperthyroidism can lead to a premature delivery, low birth weight, and miscarriage. It can also be a cause of infertility. The treatment involves medication that blocks the production of thyroid hormone.


This is when the thyroid gland produces too little thyroid hormone. The symptoms are much like the opposite of hyperthyroidism: weight gain, fatigue, constipation, feeling cold, hair loss, and dry skin are common. Pregnancy complications can arise if a woman is not treated for this (which is in the form of synthetic thyroid hormone via a prescription medication), including infertility, miscarriage, preterm birth, preeclampsia, and stillbirth.

How to diagnose these disorders 

Screening for thyroid disease is not a part of routine prenatal labs and is usually only done if a woman has symptoms, has a history of thyroid issues, or is being evaluated for other issues such as infertility. Blood tests measuring different thyroid hormones can lead to a diagnosis, and if a problem is diagnosed, these tests are usually repeated multiple times in pregnancy to make sure the treatment is adequate.

For some women, the input of an endocrinologist who specializes in hormone disorders, as well as a high-risk obstetrician, may be helpful in the management of their pregnancies. Overall, women with thyroid disorders that are adequately identified and treated have completely normal, healthy pregnancies and babies.


  • The American College of Obstetricians and Gynecologists
  • Practice Bulletin #148: Thyroid disease in pregnancy.

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