Multivariate analysis of psychomotor development in congenital hypothyroidism.

In the Finnish programme of screening for congenital hypothyroidism (CHT), thyroid replacement therapy is started very early (at a median age of 6 days). Our experience with the first 50 patients detected by this programme confirms that clinically relevant mental retardation is avoided by early therapy. But some intrauterine damage is inevitable and its degree correlates with the severity of the CHT. Age at the start of therapy, in our narrow range, did not appear to influence the outcome, as we found only a paradoxical positive correlation between the two. Our results suggest that thyroid hormone is transferred from the mother to her hypothyroid child during delivery.