بررسي مقايسه اي آزمون هاي تيروييد در سرم بند ناف نوزادان حاصل از زايمان واژينال با سزارين

The comparison of thyroid function tests in cord blood following cesarean section and vaginal delivery

The present study was designed to explore the influence of route of delivery on fetal pituitary-thyroid axis. The endocrine profiles (umbilical venous plasma) of three groups of term infants were compared immediately after delivery . Samples were taken after 30 vaginal deliveries, 30 emergency cesarean during labor and 30 elective cesarean sections before labour. The study was performed in Kowsar hospital. The samples were matched based on pariety, age, gestational age, and none of them had previous history of medical complications. Measurement of hormones was done using RIA. The mean cord serum TSH level of fetuses in vaginal or emergency cesarean group was significantly lower than that of fetuses in elective cesarean one (P<0.0001) (3.3+1.8mlu/mL, 9.0+3.2 mlu/mL, 12.1+.6.4 mlu/mL respectively). The mean cord plasma concentration of T4 and T3 were significantly higher after elective cesarean section compared with the two labour groups (P<0.05). (T4: 7.4+1.3 miug/mL, 7.4+2.4 miug/mL, 8.5+1.3 miug/mL) (T3: 0.5110.16 ng/mL, 0.62+0.12 ng/mL, 0.76+0.2 ng/mL). These results suggest that labour reduces plasma thyroid hormone concentration at birth. These adaptations seems to be as a stimulus for the subsequent surge in T3 previously reported to occur over the first few hours after birth in vaginally delivered infants.