Thyroid Hormone Profile in a Full-term Neonates with Late-onset Sepsis, an Experience from Central India: A Case–control Study

A BSTRACT Background: Neuroendocrine fluctuations, particularly thyroid hormone abnormalities, serve as critical indicators of physiological stress in septic neonates. Objective: The objective of this study was to evaluate the thyroid hormone profiles – total triiodothyronine (T3), thyroxine (T4), thyroid-stimulating hormone (TSH), and free fractions (fT3, fT4) – in septic full-term neonates and correlate these levels with the severity of sepsis and clinical outcomes. Methods: A case–control study was conducted over 1 year at a tertiary care center in Central India. The study included 50 full-term neonates (weight >2500 g, age >72 h) diagnosed with sepsis, alongside 50 age- and sex-matched healthy controls. To ensure data integrity, neonates with birth asphyxia, maternal thyroid dysfunction, or those receiving steroid therapy were excluded from the study. Cases were categorized into “probable” or “culture-proven” sepsis. Hormonal levels were measured using electrogenerated chemiluminescence, with statistical significance established at P < 0.05. Results: Among the cases, 60% were diagnosed with probable sepsis, whereas 40% were culture-proven. The mortality rate in the septic group was 30%, significantly higher than the 0% observed in controls. Data analysis revealed that mean TSH, T3, T4, fT3, and fT4 levels were significantly lower in septic neonates compared to healthy peers. Furthermore, nonsurvivors and culture-proven cases exhibited the most profound hormonal suppression compared to survivors and probable sepsis cases, respectively. Conclusion: Septic neonates exhibit significantly reduced thyroid hormone levels, with the degree of suppression directly correlating with disease severity and mortality. These findings suggest that routine thyroid function testing could be a vital tool for early risk stratification and prognostic assessment in neonatal sepsis.