Serum Thyroglobulin Levels in the Newborn

Abstract

To study the pattern of thyroglobulin (Tg) serum concentrations in the first days of life, T_g, TSH, T_3, and T₄ were measured in both maternal and cord blood at delivery and 1, 6, 12, 24, 48, 72, and 96 h after birth in 16 newborns. T_glevels at birth were higher in cord blood than in maternal blood. After birth, a prolonged Tg rise occurred. The increased levels became significant at 6 h and were maintained throughout the study. Tg levels were not correlated with serum levels of T_3, T_4, and TSH. We conclude that either a reduced Tg MCR or an increased thyroidal secretion of Tg after endogenous TSH stimulation in the newborn is a possible explanation for the elevated Tg levels occurring during the first days of life.