Diabetes and Thyroid Disorders Practice Test 2026 – Complete Exam Prep

The main idea is that pregnancy increases the need for thyroid hormone in women with hypothyroidism, so the levothyroxine dose usually has to be raised and guided by trimester-specific thyroid tests.

During pregnancy, several changes raise thyroid hormone requirements. Human chorionic gonadotropin (hCG) can weakly stimulate TSH receptors in early pregnancy, which can affect thyroid hormone levels. At the same time, estrogen rises and increases thyroid-binding globulin (TBG), which binds more thyroid hormone and lowers the free (active) fraction unless the dose is increased. The placenta and fetus also contribute to thyroid hormone use and clearance, so more is needed to maintain euthyroidism. Because these effects evolve through the pregnancy, clinicians aim for trimester-specific TSH targets and typically adjust the levothyroxine dose upward by about a quarter to a third after pregnancy recognition, with further fine-tuning as labs dictate. After delivery, the dose often returns toward the pre-pregnancy level over weeks.

That’s why this option is correct: it highlights that hCG stimulation early in pregnancy, increased TBG from estrogen, a common ~25–30% dose increase after confirmation, and trimester-specific TSH targets all inform how dosing should be adjusted.

The other ideas don’t fit the physiology. Estrogen increases, not decreases, TBG in pregnancy, so the dose doesn’t go down. No change in dose is not appropriate because hormone needs rise. Doubling the dose immediately in the first trimester is too large and not how management is done; dose adjustments are individualized and guided by labs.