Estrogen and Thyroid Hormones
A few physicians will prescribe some thyroid hormone when they prescribe an estrogen medication. Why would they do that?
Extra estrogen causes an increase in the amount of circulating thyroid binding globulin (THG). THG is a protein the "soaks up" freely circulating thyroid hormone, turning it from "free" thyroid hormone into "bound" thyroid hormone. So even though your thyroid levels might be "normal", less of what you have is active.
This shift away from "free" hormone to "bound" hormone contributes to hypothyroid symptoms such as weight gain, less energy and dry skin.
Women with PCOS may have a predisposition to "estrogen dominance".
Excessively high levels of estrogen may diminish the effectiveness of your thyroid hormones. Therefore, a full assessment of your thyroid function is suggested if you are having trouble managing your PCOS symptoms.
Source: Nutriton & Healing Newsletter, March 2004, p.4