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.

Reviewed by Dr. Jen Lincoln, December 2018


  • The thyroid gland is a gland that produces hormones that help regulate your metabolism.
  • Too much or too little thyroid hormone can lead to problems getting pregnant, as well as certain pregnancy complications.
  • Overall, women with thyroid disorders that are treated have completely normal, healthy pregnancies.


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


  1. I had sub-clinical levels of thyroid and had a history of preterm labor with all three of my girls. It was finally able to be detected and I have been receiving treatment for over 4 years now. I was also able to conceive with a much faster time. I am hoping that this is what was causing the preterm labor and it will resolve, but I am still not looking forward to the progesterone injections that I will be receiving weekly with this pregnancy. I had them with my last one as well.

    1. The issue of subclinical thyroid disease is an interesting one – more studies are showing that treating this actually has no effect on pregnancy outcomes (thought of another way: this means women shouldn’t be routinely tested or worry about their thyroid, if that helps!). However I am glad you had good luck conceiving – and I know those progesterone shots are not fun but they really help cut your risk of preterm delivery by about 50 percent – so definitely worth it! The things we do for our babies… 🙂


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