Characteristic	Selva 2002
Intervention: L‐thyroxine 50 mcg/day, n=15 Control1: L‐thyroxine 37.5mcg/day, n=15 Control 2: loading dose 50 mcg/day for 3 days, followed by 37.5mcg/day, n=17
Sex [female% / male%]	I1: nr C1: nr C2: nr Total: 47
Age [mean days (SD)]	I1: nr, < 1 year C1: nr, < 1 year C2: nr, < 1 year Total: mean age at which newborn screenign test was performed: 1.6 ( SD 1.4) days
Ethnic groups [%]	I1: nr C1: nr C2: nr
Notes	all infants recruited were enrolled in the study after detection by the Northwest Regional Newborn Screening Program
Footnotes nr = not reported