Thyroid Series (Part 2): Thyroid Changes Commonly Experienced in Pregnancy

Pregnancy causes many changes in the body – the physical ones we can see and the less obvious which are physiological and hormonal.

Your doctor will regularly check your blood work to assess any changes in your thyroid function during pregnancy. These blood tests will allow for a better overview of how well the physiological processes of your thyroid are functioning.

If you haven't read Part 1 of our Thyroid Series, you can get caught up by clicking here!

How does pregnancy affect thyroid function?

Changes in thyroid function begin during pregnancy even before most people know they are pregnant. Some thyroid hormones are influenced by changes in mom's hormone levels as well as fetal development, which might impair thyroid function. Three hormones that increase during pregnancy can cause changes in thyroid hormone levels which include human chorionic gonadotropin, progesterone, and estrogen. Pregnancy tests look for a hormone called human chorionic gonadotropin (HCG), which is produced by the first tissues that develop into the placenta. Additionally, it encourages the secretion of progesterone, which instructs the body to keep the pregnancy going. At 16 weeks of pregnancy, levels usually reach their peak and stay there until delivery. Although levels differ from woman to woman, a dramatic reduction in levels may signify the termination of a pregnancy.

HCG is closely related to TSH (see our previous blog for Part 1 for more information on TSH) and can bind to TSH receptors in the body to mimic its function. For the health of the cardiovascular system during pregnancy, estrogen is a crucial hormone. Estrogen and progesterone are the hormones that are responsible for the pregnancy “glow” since they boost blood flow to tissues, preserving the health of both the mother and the unborn child. Progesterone is also responsible for ligament laxity during pregnancy which allows the uterus to grow and expand. 

As you can see by the diagram below, thyroid function during pregnancy is incredibly complex. Iodine, which is required for the production of thyroid hormone, is one nutrient that is crucial for expectant mothers. Iodine is a component of most prenatal vitamins, and the RDA is 250 mcg per day. Dairy, eggs, meat, and iodized salt are other foods that you can eat to receive iodine in your diet.

What thyroid conditions should I be aware of during pregnancy?

Developing hyper or hypothyroidism during pregnancy can lead to complications for you and your baby, so be sure to consult with your provider and assess that your thyroid levels are within the normal range.

• Hyperthyroidism (“hyper” means too much) – this occurs when the thyroid is overactive and produces too much thyroid hormone. This condition can cause many of your body’s functions to speed up.

• Hypothyroidism (“hypo” means too little or not enough) – this is when the thyroid is underactive and doesn’t make enough thyroid hormones, so many of your body’s functions slow down.

How are thyroid conditions treated during pregnancy?

Treatment for thyroid disorders often begins with medication. You can discuss your options with your primary care doctor, or if you're expecting, you can do so with your obstetrician or midwife. Even with medication, it's important to consume a diet rich in nutrients and take supplements as needed. Incorporating a high-quality prenatal into your routine during pregnancy will also help you meet the nutritional demands of you and your baby.

In Summary

Our bodies function best when we have the right nutrients and minerals to support all of our bodily processes. When you are pregnant, you are not only supporting yourself but also your developing fetus. Be sure to consume a diet rich in nutrients and take supplements tailored to your individual needs if you have thyroid disorders because these conditions can result in a greater demand for some nutrients.

By: Dr. Megan Stavalone

Perinatal Certified Chiropractor at ANH Wellness

Disclaimer: "The information including but not limited to text, graphics, images, and other material contained on this website is for informational purposes only. No material on this site is intended to be a substitute for professional medical advice, diagnosis, or treatment."

Sources: Thyroid Physiology and Common Diseases in Pregnancy: Review of Literature https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3530964/#:~:text=The%20thyroid%20undergoes%20physiological%20changes,(TSH)%20(5). Thyroid Disease and Pregnancy https://www.niddk.nih.gov/health-information/endocrine-diseases/pregnancy-thyroid-disease#:~:text=Two%20pregnancy%2Drelated%20hormones%E2%80%94human,feel%20during%20a%20physical%20exam. Human Chorionic Gonadotropin https://www.ncbi.nlm.nih.gov/books/NBK532950/