Neonatal Screening for Hypothuroidism and its relationship to Mental Retandation

Abstract

This is the first systematic investigation for a sample of population selected for study. A total number of 1863 determinations were made. This data was prepared from 862 subjects which include neonates, established cretins, children, infants and mother. Hormone assays were made using both liquid RIA technique with serum sample and a new technique was standardise in which 1/8” discs of dry blood spots were used for assay. The later technique is extremely useful for neonates and where ethical problems associated with sample collections are to be faced. Conversion factor giving interrelationship between the two methods of assay was calculated. The result provides data for normal children profile and pattern of T4 & TSH levels from 0-9 days for neonates. Indicates a stable T4 pattern 5-9 (µg/dl) while a surge for TSH was observed within 24 hours after birth which is maintained at least up to 6th days. There is no influence of maternal hormones in this TSH surge and maternal TSH level remain within normal range. This change in TSH levels of neonates maybe regraded due to environmental change after birth. Whether raised TSH among neonates is essential to maintain a normal T4 level during the 1st week after birth or not is a point or not is a point which requires further investigation. T4 levels in relationship to FT4 levels may provide a more useful index for early diagnosis of neonatal hypothyroidism rather than T4/TSH index. Data has been provided for FT4 determination, which is a first ever report made for this category of subject. Data is also provided for established cretins in comparison to those not clinically hypo thyroids.