Pregnancy and Thyroid

The thyroid gland, a butterfly-shaped organ located in the neck, is a vital part of the endocrine system. It produces hormones that regulate the body's metabolism, which is the process of converting food into energy.  Here's how it works: 

• The thyroid gland produces two main hormones: thyroxine (T4) and triiodothyronine (T3).
•  T4, or thyroxine, is like a storage form of thyroid hormone. It circulates in your blood, but it's not the active form that your cells can use. To become active, T4 needs to be converted into T3. This happens mainly in your liver and kidneys, but also in other tissues throughout your body.
• The conversion process involves removing one iodine atom from the T4 molecule. This is done by enzymes called deiodinases. There are different types of deiodinases, and they work in different parts of the body to regulate how much T3 is produced.
• Once T4 is converted into T3, it can enter your cells and bind to receptors, triggering all sorts of important metabolic processes.                                                                                                                               

Why is the thyroid so important during pregnancy?
Your thyroid produces hormones that regulate metabolism, which is essential for energy production and overall body function. During pregnancy, your body's demand for thyroid hormones increases significantly. This increased demand is driven by several factors:

• Baby's Development: Your baby relies on your thyroid hormones for healthy brain development, especially in the first trimester when their own thyroid isn't fully formed. These hormones are crucial for neurological development, impacting everything from intelligence to motor skills.
• Maternal Health: Adequate thyroid hormone levels are essential for maintaining your own health during pregnancy. They play a role in energy levels, weight management, mood stability, and preventing complications.
• Placental Function: The thyroid also supports the healthy function of the placenta, which provides essential nutrients and oxygen to your baby.

What happens to the thyroid during pregnancy?
During pregnancy, several changes occur to ensure adequate thyroid hormone levels:

• Increased Hormone Production: Your thyroid gland naturally increases its production of thyroid hormones to meet the demands of pregnancy.
• Increased T4 to T3 Conversion: The body becomes more efficient at converting T4 (the storage form) to T3 (the active form) of thyroid hormone.

What are the most common thyroid problems during pregnancy and what issues are associated with them? 
Hyperthyroidism: This condition occurs when the thyroid gland produces too much thyroid hormone, speeding up many bodily functions. In pregnancy, hyperthyroidism is most often caused by Graves' disease, an autoimmune disorder where the immune system produces antibodies that stimulate the thyroid to make excess thyroid hormone. During pregnancy, untreated hypothyroidism can lead to complications such as preeclampsia, premature birth, low birth weight and neurological issues in baby.
Hypothyroidism: This condition occurs when the thyroid gland does not produce enough thyroid hormone, causing body functions to slow down. The most common cause of hypothyroidism is Hashimoto's disease, an autoimmune disorder where the immune system attacks the thyroid, impairing its ability to produce thyroid hormones. Untreated hypothyroidism is associated with an increased risk of miscarriage, preeclampsia, placental abruption, postpartum hemorrhage,  premature birth, low birth weight, stillbirth and transient or permanent hypothyroidism in baby.
What are the treatments for thyroid problems during pregnancy?
Levothyroxine is used to treat hypothyroidism during pregnancy. If you are already taking Levothyroxine, you may need to increase your dose.  Thyroid levels should be checked every 4 weeks during pregnancy. 
Natural thyroid hormone options like Armour Thyroid, which contain T3, are not recommended during pregnancy because they can cause lower levels of T4 in the maternal blood stream. Baby needs T4 so having lower levels will lead to decreased T4 available for baby and can lead to baby having hypothyroidism.
What can you do to support healthy thyroid function during pregnancy?

• Ensure adequate iodine intake: Follow your doctor's recommendations regarding iodine supplementation. Prenatal vitamins often contain iodine. Include iodine-rich foods like seafood (in moderation), dairy, and iodized salt in your diet. However, it's important not to overdo it with iodine, as too much can also be problematic.
• Maintain a balanced diet: A healthy diet rich in essential nutrients supports overall health, including thyroid function.

Sources:
https://www.hopkinsmedicine.org/health/wellness-and-prevention/anatomy-of-the-endocrine-system#:~:text=The%20thyroid%20plays%20an%20important,of%20the%20body's%20calcium%20balance
https://www.ncbi.nlm.nih.gov/books/NBK500006/#:~:text=The%20thyroid%20hormone%20is%20well,and%20many%20other%20bodily%20functions
https://www.ncbi.nlm.nih.gov/books/NBK537039/#:~:text=The%20thyroid%20produces%20approximately%2090,%2C%20or%20triiodothyronine%20(T3)

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