Am J Perinatol 2003; 20(6): 333-340
DOI: 10.1055/s-2003-42691
Copyright © 2003 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel.: +1(212) 584-4662

Are Perinatal Risk Factors Helpful in Predicting and Optimizing Treatment Strategies for Transient Hypothyroxinemia in Very-Low-Birth-Weight Infants?

Michelle J. Kantor Herring1 , Kathleen H. Leef2 , Robert G. Locke2,3 , John L. Stefano2,3 , Louis  Bartoshesky3,4 , David A. Paul2,3
  • 1Department of Neonatology, North Shore Medical Center, Miami, Florida
  • 2Department of Pediatrics, Section of Neonatology, Christiana Care Health Services, Newark, Delaware
  • 3Thomas Jefferson University Medical College, Philadelphia, Pennsylvania
  • 4Department of Pediatrics, Section of Medical Genetics, duPont Hospital for Children, Wilmington, Delaware
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Publication History

Publication Date:
06 October 2003 (online)


Transient hypothyroxinemia is common in premature infants and has been associated with intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), poor neurodevelopmental outcomes, and mortality. Recent trials have failed to show that supplemental thyroid hormone improves overall neurodevelopmental outcome. The objective of this article is too determine perinatal risk factors for transient hypothyroxinemia (TH). We studied a cohort of infants born between July 1993 and July 2000 who were less than 1500 g and who received a newborn screening for thyroid function (n = 932). Total serum thyroxine (T4) was collected routinely on the fifth day of life. T4 was correlated with gestational age (R = 0.59, p < 0.01). After controlling for potential confounding variables, gestational age, dopamine, and mechanical ventilation were found to be independently associated with low T4 (overall model: r 2 = 0.41, p < 0.01). Number needed to treat (NNT) analysis showed treating all infants less than 27 weeks would lead to treating 6.3 infants for every one with a subsequent T4 < 5μg/dL. By combining gestational age and need for dopamine support, NNT = 2.4 for every one infant with subsequent T4 < 5μg/dL. Low gestational age, mechanical ventilation, and need for dopamine were associated with low T4 levels and may be helpful in optimizing treatment strategies for TH.