ESPE Abstracts

Keywords: Preterm newborn, Small for gestational age, Thyroid hormones, Thyroid-stimulating hormone, Thyroid dysfunctions, Thyroid function tests.

Background: A common cause of neurodevelopmental impairment in children is congenital hypothyroidism, but can be preventable with adequate screening and proper management. Preterm newborns are more likely to have thyroid dysfunction, with small for gestational age (SGA) being an additional risk factor. However, only few studies addressed the altered thyroid hormone concentrations in the first few weeks of life concluding that TSH levels are higher in SGA newborns. As a result, we conducted a study to compare thyroid hormone levels and the incidence of thyroid dysfunction between SGA and appropriate for gestational age (AGA) infants.

Methods and materials: This is a cross-sectional retrospective single-centered study conducted at Notre Dame Des Secours University Medical Center (NDS-UMC), Byblos, Lebanon, between January 1, 2016 and November 31, 2020. The medical records including thyroid function test results, socio-demographic characteristics and clinical conditions of 260 preterm infants admitted to the NICU, were reviewed then divided into 2 groups: preterm SGA and preterm AGA newborns.

Results: A significantly higher percentage of preterm newborns who were SGA had abnormal thyroid function in general (31.8% versus 14.4%, P=0.002), and hyperthyrotropinemia in particular (18.2% versus 6.2%, P=0.004) compared to preterm AGA newborns. Moreover, preterm who were SGA had significantly higher mean TSH levels compared to those who were AGA (6.86 ± 4.31* versus 4.55 ± 3.22*, p <0.001).

Conclusion: Preterm SGA neonates had higher TSH levels and an increased incidence of thyroid dysfunction. Therefore, close follow up with periodic thyroid function testing, endocrine and cognitive assessment is of significant importance in SGA infants presenting these features. A small dose of L-thyroxin should be discussed for these preterm SGA newborns.