Background: Normal thyroid function is essential for neonatal growth and brain development. In a newborn infant with severe disease, endocrine regulation of hormones can be affected by abnormal metabolism. The assessment of thyroid parameters results in the recognition of a dysfunction and its association with disease severity. Objective: This study aimed to assess thyroid function profiles in critically ill neonates in the neonatal intensive care unit (NICU) compared with healthy controls. Additionally, we aimed to detect the presence of TD and its possible association with critical illness. Methods: A case-control study was performed in 100 neonates, comprising 50 sick neonates and 50 healthy controls. We measured thyroid function tests (T3, FT4 and TSH) within 48 h of NICU admission and documented the absence of clinical data such as GA and BW. Statistical analysis was done by Student’s t test and Mann–Whitney U test, where p 0.05). Results: Critically ill neonates had mean T3, FT4, and TSH levels of 2.3, 1.0, and 8.7, compared with 2.5, 1.1, and 8.9 in controls. Differences were not statistically significant (p > 0.05). Conclusion: The general profile of overall thyroid status was similar in the two groups but isolated cases with significantly elevated TSH encourage a close follow-up and screening.
