Haddow JE, et al. - In the Hyperglycemia Adverse Pregnancy Outcomes (HAPO) study involving 600 randomly selected non-Hispanic Caucasian women, researchers analyzed maternal BMI relationship with peripheral deiodinase activity, as well as the links between deiodinase activity, glucose and C-peptide. Among women with gestational diabetes, levels of BMI, triiodothyronine (T3)/free thyroxine (fT4) ratio and T3 were significantly higher. In accordance with reports from elsewhere, higher BMI was related to increased deiodinase activity. Increased activity of deiodinase was consequently linked to higher glucose levels.