Effect of Intra-Uterine Growth Retardation on Umbilical Cord Blood Thyroid Hormone Level

The present endeavor is an attempt to see the influence of IUGR on umbilical cord plasma thyroid hormone level in order to sort out some ideas about the far-reaching consequence of growth retardation on the development of thyroid diseases in adult life. A group of 80 term babies delivered by normal vaginal delivery from eu-thyroid mothers was selected from a tertiary care teaching hospital and categorized into case (Term babies with birth weight ? 2 kg, n=40) and control (Term babies with birth weight ? 2.5 kg, n=40). Additional 17 term babies having birth weight ranging from 2.01 kg to 2.5 kg were made a separate group and were taken into account when correlation of birth weight with thyroid hormone status was studied. Serum TSH, total T3, total T4 level was measured by Micro plate immuno-enzymatic assay and serum glucose by GOD/POD technique. The collected data was analyzed with SPPSS (version 13) statistical package using t-test. The whole 97 babies were again divided in 4 different groups with a group mean birth-weight of 1.29, 1.8, 2.3 and 3.89 kg respectively. Serum TSH, total T3, total T4 and serum glucose levels were compared among these four groups in order to study correlation between the thyroid hormone status and degree of growth retardation. The collected data was analyzed by ANNOVA test. IUGR is associated with low umbilical cord serum total T4 level. The low the birth weight of the babies the lower will be the serum total T4 level, whereas serum TSH and serum total T3 showed no correlation with birth weight. There is also significant reduction of cord plasma glucose level in SGA babies as compared to AGA babies. Term SGA babies showed isolated reduction in cord plasma Total T4 level with little or no change in cord plasma TSH level. This ’sub-clinical hypothyroidism’ in term SGA babies highlights an altered Hypothalamo-Pituitary-Thyroid axis in IUGR.