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To the Editor In a recent issue of JAMA Internal Medicine, Maraka and colleagues1 describe a clinical case of a healthy pregnant woman complaining of fatigue during early gestation (8 weeks). Thyroid function tests showed a thyroid-stimulating hormone (TSH) level of 2.8 mIU/L, leading to the diagnosis of subclinical hypothyroidism, according to the recommendations of international guidelines.1- 3 These guidelines state that in the absence of population-based reference ranges, the recommended fixed upper cutoff for TSH levels is 2.5 mIU/L during the first trimester and 3.0 mIU/L during the second trimester.2,3 In the case described by Maraka and colleagues, treatment with 50-µg levothyroxine resulted in hyperthyroid symptoms which led the patient to seek emergency care.
Korevaar TIM, Medici M, Peeters RP. Subclinical Hypothyroidism Overdiagnosis in Pregnant Women. JAMA Intern Med. 2015;175(11):1872-1873. doi:10.1001/jamainternmed.2015.5550