Neonatal thyroid-stimulating hormone concentrations in northern Sydney: further indications of mild iodine deficiency?

Objective: To determine whether thyroid-stimulating hormone (TSH) concentrations in a large sample of neonates meet World Health Organization criteria for an iodine-replete population (< 3% of neonates with whole-blood TSH concentrations > 5 mlU/L), and, in a small subset of neonates, to examine the correlation between maternal urinary iodine and neonatal TSH concentrations.

Design: Cross-sectional study of neonatal whole-blood TSH values obtained as part of a routine newborn screening program.

Setting: Royal North Shore Hospital (RNSH) in northern Sydney.