Congenital Hypothyroidism among Infants Undergoing Thyroid Function Test in a Tertiary Care Centre: A Descriptive Cross-sectional Study

Introduction: Congenital hypothyroidism is the most preventable and treatable cause of mental retardation in newborns and infants. Screening for congenital hypothyroidism in newborns and infants is not a routine practice in our part of the world. This study aimed to find out the prevalence of congenital hypothyroidism among infants undergoing thyroid function test in a tertiary care centre. Methods: A descriptive cross-sectional study was done in the Department of Biochemistry, from laboratory records starting 14th April, 2013 to 13th April, 2020 after obtaining ethical clearance from the Institutional Review Committee (Reference number: 1502/019). Data of infants whose thyroid function tests were performed were obtained using convenience sampling. Thyroid-stimulating hormone was categorised per the European Society of Paediatric Endocrinology guidelines. Data were entered and analysed using Microsoft Excel 2011 and the Statistical Package for the Social Sciences version 11.5. Point estimate at a 95% Confidence Interval was calculated along with frequency and percentages for binary data. Results: Among 1243 infants, 56 (4.50%) (3.35-5.65 at 95% Confidence Interval) infants were diagnosed with congenital hypothyroidism. Conclusions: The prevalence of congenital hypothyroidism was higher than other studies done in similar settings. An unexpected finding of treatment-induced hyperthyroidism was observed, indicating a lack of regular and timely follow-up of infants diagnosed with congenital hypothyroidism.