[Congenital hypothyroidism: results of screening 30 000 neonates in lower saxony (author's transl)].

While screening 30 000 children for congenital hypothyroidism by radioimmunological determination of thyroid stimulating hormone (TSH) in blood spotted on filter paper on the 5th day of life, 12 neonates were found with this condition. In addition 99 infants were found who showed temporarily elevated TSH levels (20-80 microU/ml). Seven of the transitory cases could be traced to a vaginal application of povidone-iodine in the mother. Alimentary iodine deficiency, which is known to exist in parts of Lower Saxony, may be another explanation for some of the others.