Thyroid Function in the Perinatal Period

Abstract

<h3>Introduction</h3> A better knowledge of thyroid function during the perinatal period should provide the basis for improved management of thyroid disorders of infants and should serve as a key to better understanding of the role of the thyroid gland in fetal growth and development. Thyroid function during the perinatal period in mothers and infants, as indicated by serial variation in the concentration of serum butyl-extractable iodine (BEI), has not been wholly defined.^1-4We have undertaken this study with use of a sensitive micromethod developed in our laboratory for the BEI determination.⁵ Studies to be presented include a series of BEI determinations on mothers and their progeny in the perinatal period and, in addition, supplemental studies of chemical and I131-tracer analyses of thyroid glands in puppies. The latter studies were designed to elaborate specific features of thyroid hormone synthesis and release. <h3>Methods</h3> <i>Clinical Study.</i>—Duplicate serum BEI determinations were