Lau L, Benham JL, Lemieux P, et al. - In this systematic review and meta-analysis of randomised controlled trials, researchers sought to assess the impact of levothyroxine therapy on pregnancy outcomes compared with placebo or no treatment in women without overt hypothyroidism with the presence of thyroid peroxidase antibodies (TPOAb) and/or thyroglobulin antibodies (TgAb).Randomised trials of levothyroxine vs control (placebo or no treatment) among women with positive TPOAb or TgAb who were pregnant or considering conception were the recommended inclusion criterion. The sample consisted of 2,263 women. There is a lack of evidence of the benefit of the use of levothyroxine among pregnant women or women planning conception with thyroid autoimmunity (moderate to high Grading of Recommendations, Assessment, Development and Evaluations). It is important to rethink the guidelines for using levothyroxine in this setting.