Tamizaje neonatal de hipotiroidismo congénito, análisis de la evidencia actual y propuesta de tamizaje para la población mexicana

Abstract

In recent years, the incidence of congenital hypothyroidism has almost doubled; this is attributed to the increased number of premature births and multiple pregnancies, changes in the design of current neonatal screening programmes, and to the improvement in available laboratory techniques, which have allowed the detection of subtle forms of the disease.

Screening strategies vary according to the objectives of each programme and in recent decades, there has been controversy about: a) the ideal method of detection: TSH (thyrotropin), thyroxine (T4) or simultaneous T4 and TSH, b) the usefulness of the decrease in TSH cut-off in whole blood recently implemented and c) the need for re-screening among premature newborns with low birth weight, Down syndrome, and other high-risk populations.

Although the benefit of early treatment of severe cases of congenital hypothyroidism to prevent mental retardation is clear, most of the new cases detected with the new strategies are mild, such as transient and persistent neonatal hyperthyrotropinaemia, for which the usefulness of treatment in neurocognitive development has not been proven in randomized clinical trials. The objective of this article is to make a screening proposal in the Mexican population based on the current available evidence and to establish future research areas that help to resolve these controversies.