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Am J Perinatol 2021; 38(12): 1271-1276
DOI: 10.1055/s-0040-1712168
Original Article

Hypothyroxinemia Detected at 4 Weeks of Life in Preterm Infants Born at Less than 30 Weeks of Gestation

Dinushan C. Kaluarachchi
1   Department of Pediatrics, University of Wisconsin-Madison, Madison, Wisconsin
,
Tarah T. Colaizy
2   Department of Pediatrics, University of Iowa, Iowa City, Iowa
,
Michael R. Lasarev
3   Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, Wisconsin
,
David B. Allen
1   Department of Pediatrics, University of Wisconsin-Madison, Madison, Wisconsin
,
Jonathan M. Klein
2   Department of Pediatrics, University of Iowa, Iowa City, Iowa
› Author Affiliations Funding None.
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Abstract

Objective Data on free thyroxine (FT4) concentrations beyond first 2 weeks of preterm infants are limited. This study was aimed to describe the association between perinatal characteristics and FT4 concentrations and the incidence of hypothyroxinemia at 4 weeks.

Study Design Retrospective analysis of serum thyroid function tests at 4 weeks in preterm infants <30 weeks of gestation. Association between FT4 at 4 weeks of life and perinatal characteristics were determined by bivariate analysis and multivariable regression. Incidence of hypothyroxinemia was determined using a gestational age adjusted definition based on in utero levels at the equivalent postmenstrual age.

Results The study cohort consisted of 280 infants. FT4 concentrations at 4 weeks of life were significantly associated with gestational age, birth weight, gender, and maternal history of thyroid disease. Hypothyroxinemia was found in 32.8% of the study cohort.

Conclusion Perinatal characteristics are associated with FT4 concentrations at 4 weeks of life. Nearly one-third of infants born <30 weeks had hypothyroxinemia at 4 weeks of life when compared with in utero levels at the equivalent postmenstrual age.

Keywords

hypothyroxinemia - thyroxine - preterm infants

Authors' Contributions

D.C.K. designed the study, drafted the project proposal, collected data, and drafted and approved final manuscript as submitted. T.T.C. involved in designing of the study, reviewed, and approved final manuscript as submitted. M.R.L. involved in designing of the study, did the data analysis, reviewed, and approved final manuscript as submitted. D.B.A. involved in designing of the study, reviewed, and approved final manuscript as submitted. J.M.K. involved in designing of the study, reviewed, and approved final manuscript as submitted.




Publication History

Received: 03 December 2019

Accepted: 14 April 2020

Article published online:
04 June 2020

© 2020. Thieme. All rights reserved.

Thieme Medical Publishers
333 Seventh Avenue, New York, NY 10001, USA.

 

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