A 40-year-old woman presents with fatigue, weight gain and constipation. TSH is 18 mIU/L (0.4-4.0) and free T4 is low. She is otherwise healthy and not pregnant. What is the MOST appropriate initial treatment?AObserve and repeat thyroid function tests in 6 monthsBStart levothyroxine 25 µg daily and recheck in 1 yearCStart levothyroxine 1.6 µg/kg/day and recheck TSH in 6-8 weeksDStart liothyronine (T3) monotherapyERefer urgently to endocrinology without starting treatmentCheck my answer