If the pregnant patient is already on a low dose of thionamide (≤5–10 mg/day methimazole or ≤100–200 mg/day PTU), a trial off pharmacotherapy may be warranted based on recent thyroid function tests, TRAb levels, treatment history, and goiter size, with a goal to keep T4 < 1.5 times the upper reference limit [135]. Here, CD4 is linked to goiter.