Final answer:
Oral estrogen can impact thyroid levels by affecting the production, transport, and metabolism of thyroid hormones. It may increase levels of thyroid-binding globulin (TBG), which can lead to an increase in total thyroid hormone levels.
Step-by-step explanation:
Thyroid hormones play a significant role in various body functions, including metabolism, protein synthesis, and development of the nervous system. Oral estrogen can have an impact on thyroid levels. It can affect the production, transport, and metabolism of thyroid hormones, which may lead to changes in thyroid function. For example, some studies suggest that oral estrogen may increase levels of thyroid-binding globulin (TBG), a protein that transports thyroid hormones in the blood. This can result in an increase in total thyroid hormone levels in the body, while the levels of free, active thyroid hormones may remain relatively unchanged.