Neonatal thyroxine supplementation in very preterm children: developmental outcome evaluated at early school age

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J M Briët1, A G van Wassenaer, F W Dekker

  • 1Department of Neonatology, University of Amsterdam, Amsterdam, The Netherlands. j.m.briet@amc.uva.nl

Pediatrics
|May 23, 2001
PubMed

Insights

Thyroxine (T4) supplementation in extremely premature infants showed benefits for cognitive and motor outcomes in those born before 29 weeks gestation. However, T4 supplementation was linked to developmental issues in infants born at 29 weeks gestation.

Area of Science:

  • Neonatal Medicine
  • Developmental Pediatrics
  • Endocrinology

Background:

  • Transient hypothyroxinemia in very premature infants is linked to developmental challenges.
  • Previous studies indicated thyroxine (T4) supplementation improved mental outcomes at 2 years for infants born at 25/26 weeks gestation.
  • The long-term effects of T4 supplementation beyond 2 years were previously unknown.

Purpose of the Study:

  • To evaluate the effects of neonatal thyroxine (T4) supplementation on neurodevelopmental outcomes at early school age (5.7 years).
  • To assess cognitive, behavioral, and motor development in survivors of a randomized, placebo-controlled T4 supplementation trial.

Main Methods:

  • A randomized, placebo-controlled trial involving 200 infants born before 30 weeks gestation.
  • Survivors were assessed at 5.7 years using standardized cognitive, behavioral, and motor assessments.
  • Neurologic functioning was qualitatively assessed.

Main Results:

  • Thyroxine (T4) supplementation showed benefits for children born before 29 weeks gestation, particularly those born at 25/26 weeks.
  • A 10-point IQ difference favored the T4 group in infants <27 weeks gestation.
  • In contrast, infants born at 29 weeks gestation showed a 15-point IQ difference favoring the placebo group.
  • Behavioral outcomes varied, with fewer problems in the T4 group for 25/26-week infants but more problems for 27-week infants.
  • Motor and neurologic outcomes favored T4 treatment for infants <29 weeks gestation, but not for those born at 29 weeks.

Conclusions:

  • Neonatal thyroxine (T4) supplementation offers developmental benefits for extremely premature infants born before 29 weeks gestation.
  • The most significant benefits were observed in infants born at 25/26 weeks gestation.
  • Conversely, T4 supplementation in infants born at 29 weeks gestation was associated with adverse developmental outcomes.
Abstract

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