ABSTRACT
It is has been known that the treatment with thyroxine in hypothyroid children results in normal physical growth, but mental development is less predictable. A comparative study of developmental milestones, anthropometry and intelligence quotient (IQ) in congenital hypothyroid children starting thyroxine therapy before and after 6 months of age was done. Forty-eight congenital hypothyroid children were enrolled. They were given thyroxine and were followed up. In 18 cases who received thyroxine at or before 6 months of age their anthropometric measurements in majority were 50th percentile or above. Their mental age was deficient on an average by 5 months as compared to chronological age and their IQ was above 85. In rest of 30 cases where thyroxine was started after 6 months of age anthropometric measurements in majority were less than 50th percentile. Their mental age was deficient on an average by 14 months with IQ ranging between 50 and 70. Thyroxine therapy before 6 months of age considerably improved mental function so that they are educable. On the contrary those with late thyroxine therapy showed mild to moderate mental retardation and need special care. In developing country like ours if treatment of hypothyroidism can be started even by 6 months of age considerable brain function can be salvaged so that they can attain a self supportive life.