Study title: Thyroid hormone levels with change in HIE stages in term neonates.

Background: Perinatal asphyxia causes reduced supply of oxygen to almost all organs of the body. It causes Hypoxic Ischaemic Encephalopathy (HIE) in the brain which alters the level of thyroid hormones. There are very few studies which suggest how hypoxia and ischemia affects the level of thyroid hormone. Aims: To study the change in level of thyroid hormones(T3, T4 and TSH) in cord blood and venous blood at 18-24 hrs of life in different grades of HIE (Stage I, II, and III) Material and Methods: It was a Prospective Cohort study with a total of 60 full term neonates that required ventilation by bag and mask for >1min or APGAR scored < 7at 1 and 5 minutes or required intubation. According to Sarnat and Sarnat staging criteria babies staged as stage I, II and III. Cord blood samples and venous blood samples at 18-24 hours of life were taken and changes in level of thyroid hormones (T3, T4, TSH) were observed with radioimmunoassay. Student's T test used to assess continuous variables with a confidence limit of 95% and significance level of 5%. Results: In newborns of HIE Stage I, there was no significant difference between the mean levels of T3, T4 and TSH in cord blood and 18-24 hours sample. On the contrary in newborns with HIE Stage II and III we found a statistically significant decrease in the mean levels of T3, T4 and TSH in 18-24 hours sample after birth as compared to that of cord blood. Conclusion: InNeonates with higher grades of HIE there is decrease in physiological TSH surge which leads to diminished increase in T3 and T4. [ABSTRACT FROM AUTHOR]