[Subclinical hypothyroidism--what level of TSH is an indication for substitution?]

Overt hypothyroidism is always an indication for substitution with levothyroxine. In patients with subclinical hypothyroidism and clearly elevated TPO antibodies, a wish to bear a child, infertility, and pregnancy, as also hypothyroidism-associated symptoms, including depression, a trial substitution with levothyroxine is justified. Before long-term treatment is initiated, an improvement in the clinical symptoms must be confirmed. Even though levothyroxine reduces the LDL cholesterol, or other risk factors are improved, it has not so far been unequivocally shown that levothyroxine reduces morbidity and mortality. These questions should be investigated in prospective clinical studies.