Results: Meanage of the study group was 23.46±3.07 years, andthat of controls was 23±2.8 years. In Phase A, serum TT3 & TSH levels were significantly higher than in controls [1.479±0.52 vs 1.248±0.3 ng/mL &
3 (0.9-6.5) vs 1.2 (0.4-3) μIU/mL respectively; P< 0.05]. In Phase B, there were fall in levels of TT3,
TT4, but TSH decreased significantly [1.8(0.6-6) vs 3 (0.9-6.5) μIU/mL; P< 0.05]. In Phase C, TT3 showed significant fall [1.117±0.39 vs 1.421±0.4 ng/mL; P< 0.05]. Conclusion: All the values ofthyroid function test were within normal range in controls & study group in all phases. All alterations, the significant rise in TT3 in Phase A, and the fall in phase C and the significant rise in TSH in Phase A and the fall in Phase B, seen during labor seemed to be need based and was significantly influenced by stress present during labor.