Somatosensory Evoked Potentials in Very Preterm Infants in Relation to l-Thyroxine Supplementation

Abstract

Objective. To study the effect ofl-thyroxine supplementation on neurologic maturation in very preterm infants with transient hypothyroxinemia. Design. Randomized, double-blind, placebo-controlled,l-thyroxine supplementation trial. Setting. Level III neonatal intensive care unit. Subjects. A total of 200 infants <30 weeks' gestational age. Intervention. Subjects were randomly assigned to receivel-thyroxine (8 μg/kg birth weight per day) or a placebo during the first 6 weeks of life. Methods. Median nerve somatosensory evoked potentials were recorded, measuring cortical N1 peak latency at 2 weeks of age, at term, and at 6 months (corrected) age. Results. Cortical N1 peak latency was not decreased significantly in the l-thyroxine group compared with the placebo group throughout the study period. Conclusion. l-Thyroxine supplementation during the first 6 weeks of life did not decrease cortical N1 peak latency in infants of <30 weeks' gestational age.