Is it necessary to increase thyroid medications when pregnant. my doctor said not necessary and ended up with blighted ovum. wondering if thats the cause?

Thyroid disease ?'s: Pregnancy will increase total thyroid levels due to increased binding of T3 by globulins. The amount of "free" (unbound) T3 is critical to assess in pregnancy, but is a rare cause of a "blighted ovum", which is a relatively common occurrence. Generally it is not necessary to "increase thyroid hormone" in pregnancy, but ask for a referral to an endocrinologist to be certain about your case.