Thyroxine administration to infants of less than 30 weeks' gestational age does not increase plasma triiodothyronine concentrations

Abstract

Daily T4 administration during the first 6 weeks after birth to infants of less than 30 weeks gestation prevents hypothyroxinemia, but decreases plasma T3 concentrations. Our finding possibly implies that very preterm infants should receive supplements of both T4 and T3.