Congenital Hypothyroidism: Need for Universal Neonatal Screening

Normal thyroid function is essential for brain development postnatally, in the first two to three years of life. Over 80% newborns with congenital hypothyroidism appear normal, and cannot be suspected to have CH on the basis of clinical features alone. Delayed thyroxin replacement results in permanent mental retardation. Therefore, neonatal thyroid screening programs have been set up in developed countries, so that appropriate replacement can be started in the first 2 weeks of life. These programs have been shown to be highly cost effective. Worldwide, CH occurs in 1/3,000-4,000 newborns; in India, where the incidence may be higher, screening is not being done universally. In Indraprastha Apollo Hospital, the neonatal team has been screening all newborns (inborn and outborn) almost since its inception (Jan 1997). Most countries have opted for primary TSH screening, while the US uses primary T4. For logistical reasons, we have so far done both tests in each baby, and have moved from screening in the second week of life, to just before discharge (48-72 hrs of life), to testing in the cord blood (liquid sample, not filter paper), keeping the TSH cut-off as 30 uU/ml. Our incidence appears to be much higher than the universal incidence.