Abstract

Objective: Congenital hypothyroidism (CH) is the leading cause of mental retardation worldwide although preventable. The prevalence of congenital hypothyroidism is about 1/3000. Hypothyroidism is more frequent in preterm infants, especially in sick preterms, than in term infants. In our study, we aimed to ascertain the frequency of CH in very low birth weight preterm infants (VLBW, <1500 g).

Material and Methods: The study was carried out on the basis of the  retrospective evaluation of medical records in VLBW infants who were hospitalized in a period of 52 months. Thyroid function tests (TFT) [free thyroxine (sT4), thyroid  stimulating  hormone  (TSH)]  were  recorded  in  patients  who  survived  5  days  following  the  first  admission. Patients with abnormal TFT results were divided into subgroups according to the control TFT results. Thyroid hormone supplementation was administered for the CH group.

Results: A total of 581 patients where TFT results for the 5th day were available were included in the study. The first TFT results of 79 patients was abnormal. In the second control, 26 patients were diagnosed with CH because of abnormal TFT values and thyroid hormone supplementation was administered. In VLBW infants, the rate of CH was 4.4% (1/23). In addition, the gestational age and birth weight of the patients with CH was significantly lower (p=0.000, p=0.037) and the female sex ratio was higher (p=0.017).

Conclusion: The rate of congenital hypothyroidism was found to be higher in the female gender with a lower gestational age and birth weight in the preterm infants. Thyroid dysfunction is prevalent in preterm infants. While considering the neurodevelopmental consequences especially in preterm infants, it is important to ensure re-measurement of thyroid function tests to identify CH.

Keywords: Very low birth weight, Congenital hypothyroidism, Premature, Thyroid dysfunction

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Copyright © 2019 The Author(s). This is an open access article distributed under the Creative Commons Attribution License (CC BY), which permits unrestricted use, distribution, and reproduction in any medium or format, provided the original work is properly cited.

How to cite

1.
Çakır U. Evaluation of Thyroid Functions in Very Low Birth Weight Preterm Infants. Turk J Pediatr Dis [Internet]. 2019 May 24 [cited 2025 Aug. 23];13(3):165-70. Available from: https://turkjpediatrdis.org/article/view/608