Most common cause of Neonatal Hypothyroidism is

Iodine deficiency is the commonest cause of congenital hypothyroidism in ceain pas of India, while thyroid dysgenesis is the most common aetiology in non-endemic areas (75% of all cases). Thyroid scan pictures showing different types of thyroid dysgenesis. At upper panel hypoplasia (A), hemiagenesis (B), ectopia (C), double ectopia (D), and athyreosis (E) compared with normal thyroid (G) shown at lower panel. Panel F showing scintigraphy performed at the time of diagnosis (F1 and F2) repoed as hemiagenesis while repeated scintigraphy at the time of the study (at 12 years age) showed ectopia (F3). Radiopharmaceutical uptake by thyroid tissue is shown by black arrows and salivary glands by empty arrows. Reference: Ghai essential of paediatrics, eighth edition, p.no:516