The Assessment Of Thyroid Hormone Levels In Term And Preterm Infants Diagnosed With Transient Tachypnea Of The Newborn: A Cross-Sectional Study

Aim: The study aims to evaluate the effect of thyroid hormone levels on the development of transient tachypnea of the newborn (TTN) and neonatal outcomes in preterm and term infants during hospitalization.Methods: Eighty-seven newborns with gestational age >= 34 weeks admitted to neonatal intensive care unit (NICU) between January 2016 and December 2019 were enrolled in our retrospective study. The hospital database system and patient files were scanned for data collection. Infants were divided into three groups (late preterm, early term, and term). Maternal features and demographic characteristics, thyroid hormones, neonatal outcomes during hospitalization of newborns with TTN were recorded.Results: The mean fT4 level was 1.51 +/- 0.33 ng/dL and the median thyroid-stimulating hormone (TSH) level was 3.1 mIU/L. Among 87 infants, 21 were late-preterm, 41 were early-term, and 25 were term infants. There was no difference in the mode of delivery, gender, need, and duration of mechanical ventilation, and non-invasive ventilation or O-2 therapy. The mean fT4 level was 1.35 +/- 0.29 ng/dL in late preterms 2.5 +/- 2.1 ng/dL in early terms and 1.56 +/- 0.25 ng/dL in term infants. Late preterms had a lower fT4 level than early term and term groups which was statistically significant but no difference was present between subgroups in TSH levels.Conclusion: Evaluation of thyroid function should be considered especially in preterm babies hospitalized to NICU because of respiratory distress for an individualized approach if treatment is needed.