Archives of Disease in Childhood

Abstract

As far as can be ascertained from the literature, the administration of thyroid gland to premature babies was first suggested by Pritchard (1934). He then described its use in his book on ' The New Born Baby, ' but he was certainly advocating this therapeutic measure long before this time. The underlying principle for this form of treatment is of much earlier date and goes back to the classical experiments of Gudernatsch (1913-14), on the feeding of tadpoles with thyroid gland to speed up their development into frogs. This pioneer's conclusions were as follows: ' The experiments of 1911 and 1912 leave no doubt that the mammalian thyroid contains an agens which, when given as food, calls forth a rapid differen-tiation in a developing vertebrate organism.' The object of administering thyroid gland to the premature baby is to hasten maturation, so that the various essential functions, such as those of respiration, digestion and heat regulation, may be more expertly undertaken than in the immature state. It is differentiation of function and structure which is achieved in the tadpole, and not growth. In fact, the resulting frog will usually be undersized and its length of life is generally shorter than the average. In the premature baby the use of thyroid should be limited to such a period as seems necessary to improve functional development. The gland is not being used to supply a deficiency, but merely to act as a stimulant to remove the inertia which makes the premature baby so difficult to manage. This point on the question of a possible deficiency of thyroid secretion in the premature baby must be elaborated briefly, for Collis (1936), in strongly supporting the use of thyroid for premature babies, has suggested that new-born babies do not in general secrete thyroxin in the first few weeks of life, implying that the premature baby may be handicapped on this account. Histological evidence (Murray, 1927) does not support this view. The thyroid gland in the full-term human foetus and in the newly born infant presents a normal colloid