Congenital hypothyroidism screening by umbilical cord blood: thyroid stimulating hormone

Background: Congenital hypothyroidism (CH) is one of the common preventable cause of intellectual disability. Most cases of CH result from thyroid dysgenesis. CH is often asymptomatic in early infancy, and any delay in treatment can affect the child in terms of delayed cognitive milestones. NSCH (newborn screening for congenital hypothyroidism) has been universally accepted and it is one of the most cost effective screening programs in the field of preventive medicine and public health. Methods: A cross sectional study was conducted in Sri Venkata Sai Medical College and Hospital from 28 August to 28 February 2019 (1.5 years), this study was done on 73 newborns (70 deliveries, three mothers gave birth to twins). All data was collected prospectively. Mothers with known thyroid disease or on thyroid medication were excluded from the study. Under sterile aseptic conditions blood sample is collected from the umbilical cord soon after delivery. Results: In the present study Cord blood TSH level of >20 mIU/L was present in 10% (7) of neonates. When the blood TSH levels were repeated (on day 3) among those with high cord blood TSH levels (>20), the blood TSH levels was also high (>20) in 6 (85.7%) neonates and low (<20) in 1 (14.2%). In Neonates with cord blood TSH >20, 6 neonates also had Low T4 (T4<7) levels (85.7%) and 1 neonate (14.2%) had T4 >7. In the present study 6 neonates (85.7%) had Congenital Hypothyroidism. The present study finds that Cord blood TSH as a diagnostic tool has Sensitivity of 100% and specificity of 98.5% in diagnosing congenital hypothyroidism. Conclusions: The current study concludes that Cord blood TSH is a sensitive and specific marker to predict the presence of congenital hypothyroidism in neonates.