The common pattern in women with recurrent miscarriage.
Their TSH is normal. Their thyroid function has been checked and cleared. They have been told their thyroid is not a factor.
And yet when you test their thyroid antibodies TPO antibodies and thyroglobulin antibodies they come back significantly elevated.
Nobody had ever tested them before.
This post is about that gap. About why thyroid antibodies matter independently of thyroid function. About why a normal TSH does not rule out thyroid autoimmunity as a cause of miscarriage. And about what can be done when antibodies are found.
THE DIFFERENCE BETWEEN THYROID FUNCTION AND THYROID AUTOIMMUNITY
This distinction is at the heart of everything in this post and it is one that is almost never explained to patients.
Thyroid function refers to how well the thyroid gland is producing hormone. It is measured by TSH, Free T4, and Free T3. When these are within the normal range, thyroid function is considered adequate.
Thyroid autoimmunity refers to whether the immune system is attacking the thyroid gland. It is measured by TPO antibodies (thyroid peroxidase antibodies) and thyroglobulin antibodies (TgAb). These can be elevated regardless of whether thyroid function is currently normal.
