THYROID function of the newborn was studied by Danowski and co-workers1 and by Man and co-workers,2 who determined the plasma level of the thyroxine-like protein-bound iodine and butanol-extractable iodide. In infants 1 to 3 days old protein-bound iodine averaged 12.0 γ per 100 cc., and butanol-extractable iodine in infants of 2 to 6 days was 7.0 to 11.7 γ per 100 cc. These results are compatible with hyperthyroidism in adults or older children.2 Several reports * indicated that I131 uptakes by the thyroids of normal children "less than 1 year" to 14 years of age were well within the broad range of normal adults, i. e., less than 50% of the injected dose of I131 accumulated in the thyroid area after 24 or 48 hours.
Apparently, no I131 studies have been reported on newborn infants. The absence of such studies results partly from the previous