Premium
CHANGES IN SERUM CONCENTRATIONS OF THYROID HORMONES AND THYROID HORMONE‐BINDING PROTEINS DURING EARLY INFANCY Studies in Healthy Fullterm, Small‐for‐gestational Age and Preterm Infants Aged 7 to 240 Days
Author(s) -
JACOBSEN B. BROCK,
HUMMER L.
Publication year - 1979
Publication title -
acta pædiatrica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 115
eISSN - 1651-2227
pISSN - 0803-5253
DOI - 10.1111/j.1651-2227.1979.tb05029.x
Subject(s) - medicine , small for gestational age , thyroxine binding globulin , endocrinology , transthyretin , triiodothyronine , albumin , gestational age , congenital hypothyroidism , globulin , serum concentration , hormone , thyroid , pregnancy , biology , genetics
Abstract. Serum concentrations of thyrotropin (TSH), thyroxine (T 4 ), triiodothyronine (T 3 ), thyroxine‐binding globulin (TBG), prealbumin (TBPA) and albumin (Alb) were determined in 492 blood samples from 127 fullterm (FT), 91 small‐for‐gestational age (SGA) and 88 preterm (PT) healthy infants aged 7 to 240 days. Serum T 4 decreased about 20% during the first month of life. In infants aged 7–49 days, serum T 4 concentrations were significantly lower in SGA than in FT infants, and even lower values were found in PT infants. Serum T 3 increased 50–70% reaching maximal values by 50–79 days of life. Serum T 3 levels were higher in FT than in SGA infants throughout the observation period. In PT infants serum T 3 increased from low values to levels which exceeded those of SGA and FT infants by 120–240 days of life. Serum TSH level did not change with age and was 5 mU/1 in all infants. Serum TBG values were high compared to normal adult values and did not change significantly with age. Comparable serum TBG values were found in FT, SGA and PT infants. Serum TBPA increased with age. Serum TBPA increased gradually in FT infants. In SGA infants serum TBPA increased from low values to levels which by 120–240 days of life exceeded those of PT and FT infants. In PT infants a decrease in serum TBPA appeared before the rise commenced. Serum Alb increased gradually in FT, SGA and PT infants during the observation period. Serum Alb in PT infants aged 30–119 days was lower than those in FT infants with similar ages. These physiological changes in serum concentrations of thyroid hormones and hormone‐binding proteins during early infancy should be considered when interpreting thyroid function tests in infants with various maturity.