Gender disparities in screening for congenital hypothyroidism using thyroxine as a primary screen.

Abstract

Newborn screening for congenital hypothyroidism (CH) is based on testing for the markers thyroxine (T4) and/or thyroid-stimulating hormone (TSH). Diagnosis of CH is complicated because many factors affect the levels of these hormones including infant birth weight, prematurity and age at specimen collection. We investigated whether the sex of the newborn affected the levels of T4 and TSH and consequently the outcome of newborn screening.