THYROID STIMULATING HORMONE LEVELS AMONG NEWBORN AND ASSOCIATION WITH CONGENITAL HYPOTHYROIDISM IN A TERTIARY CARE HOSPITAL OF NORTH INDIA

Background: Newborn screening for hypothyroidism has been very valuable to detect hypothyroidism in neonatal period. And early thyroxin replacement has improved neurological development and physical growth of such babies. Screening for TSH early in neonatal life, the necessity of doing confirmatory tests is still unclear. CH is one of the most common preventable causes of intellectual disability [1]. Screening programs for CH have been developed in many countries Objectives: The study was done to find the incidence of congenital hypothyroidism as well as the association of congenital hypothyroidism with serum TSH levels (10-20mIU/L.) Methods: In a prospective study, the various characteristics of the Newborn like birth weight, gender, gestational age and maternal thyroid status were recorded, stable newborn babies beyond 34 weeks of gestational age were screened for congenital hypothyroidism using venous TSH levels. Those with TSH levels ≥ 10mIU/L were subjected to confirmatory free T4 and TSH levels test for diagnosis based on recommendations of the Indian Society for Pediatric and Adolescent Endocrinology (ISPAE). The association between screening TSH levels 10-20mIU/L and congenital hypothyroidism was also studied. Results: 3000 neonates were screened for congenital hypothyroidism. 350 (11 %) were retested with free T4 and Serum TSH levels. Out of 350 newborns 10 were diagnosed as case of CH and started on levo thyroxin Overall incidence of CH among screened babies was 0.3%. There was significant association between screening TSH levels and congenital hypothyroidism. Two newborns (0.06%) and 8(0.2%) newborns diagnosed with congenital hypothyroidism had screening TSH levels in the range of 10-20 mIU/L and >20mIU/L respectively, but this association was not found to be statistically significant. Combined Repeat TSH and Free T 4 was more accurate but costly. Conclusion: Screening newborns for TSH levels and high index of suspicion when TSH is as low as 10mIU/L, recommending retest after 20 days of life to detect CH early in life and prevent treatable cause of mental retardation.