These hormonal changes and metabolic demands occur not only in pregnancy, but
also in labor and puerperium and result in profound alteration in the biochemical parameters of thyroid function. Important changes in thyroid economy during various trimesters of pregnancy have been studied extensively. However there is little information from India about thyroid economy during labor and role of these thyroid hormones in labor, and the data reported on thyroid function during labor and immediate puerperium vary. Banovac K et al. reported that after delivery, serum TT3 and T4 fell transiently with a simultaneous increase in reverse T3, whereas serum TSH concentration showed no significant variation12. González-Jiménez reported that serum TSH levels showed a
slight increment during gestation with a significant decrease (p