Controlled Antenatal Thyroid Screening II: effect of treating maternal suboptimal thyroid function on child cognition

The Controlled Antenatal Thyroid Screening (CATS) study started in 2002 and was the first randomized controlled trial to evaluate the effect of screening and treatment of mild hypothyroidism during pregnancy on child cognition1. A large number of women (n=21,846) were recruited at a median of 12 gestational weeks in UK and Italy, and offspring of mothers with gestational mild hypothyroidism (median TSH 3.6 mU/L) or hypothyroxinemia (median FT4...