From the Dept. of Pediatrics, Endocrinology and Metabolism Division, Shiraz University of Medical Sciences, Shiraz, Islamic Republic of Iran
Abstract: (4440 Views)
Birth is associated with significant changes in the hypothalamic-pituitarythyroid
axis and these changes complicate the proper assessment of thyroid
function in neonates. Normal values forT4 (thyroxine) and TSH (thyroid stimulating
hormone) in cord blood are not well established. The present study was carried out
on 4000 specimens of cord sera of both sexes in order to establish reliable reference
values for these hormones. Our data imply that the level ofT4 in cord sera (mean±
1 SD: 10.99±2.46 µg/dL) is less than that of the neonatal period but is comparable
to that of older infants. The concentration of TSH (mean±1 SD: 7.09+4.54µU/mL)
is comparable to the level expected in the first week of life but is higher than that
of older infants. The values of T4 and TSH obtained from cord blood of boys and
girls did not show any statistically significant differences.
It is suggested that these values can be used as normal reference values for T4
and TSH in cord blood.