[Neonatal diagnosis of hypothyroidism by measurement of TSH levels: results in a series of 1880 cases from the University Hospital Center in Caen (author's transl)].

Early substitutive hormonal treatment for congenital hypothyroidism is the main factor affecting the prognosis of mental abnormalities. Therapy should be instituted in the first few weeks of life but clinical diagnosis is usually very difficult at this stage and biological criteria have to be used as a basis for establishing the diagnosis during the neonatal period. For this reason, TSH levels were measured in 1880 babies on the 4th day of life. This enabled a diagnosis of thyroid agenesia to be made in a case where no tangible clinical signs were present, and treatment could be started on the 12th day of life. Furthermore, two cases of hypothyroidism from iodine overdosage during amniography were discovered and early treatment instituted. The results of this study, which was limited to only one maternity unit, demonstrate the value of systematic diagnostic procedures for congenital hypothyroidism. It also underlines the danger of iodine overdosage during foetal life which could contra-indicate the use of amniography.