Perinatal thyroid discharge. A histological study of 1225 infant thyroids.

A random sample of 500 infant thyroids in which post-mortem changes were, as far as possible, eliminated was studied histologically. In the great majority of neonatal thyroids there are distinct changes which suggest the occurrence of an acute `perinatal thyroid discharge' probably due to over stimulation, and which are confined to the immediate perinatal period. These changes are characterized by (i) reduction and loss of colloid (often complete), (ii) vacuolation and detachment of cells, (iii) irregular and pyknotic nuclei, and (iv) the presence of nuclear knots. The thyroid changes are probably physiological and labour-related. The only clinical symptom found to be related to neonatal thyroid discharge was sclerema neonatorum, when there appeared to be an absence of thyroid reaction.