Neurodevelopment in Children Born to Hypothyroid Mothers Restored to Normal Thyroxine (T4) Concentration by Late Pregnancy in Japan: No Apparent Influence of Maternal T4Deficiency

The importance of maternal T₄ for brain development prior to the onset of fetal thyroid function has been suggested in basic studies, and a correlation between mild maternal T₄ deficiency in early gestation and disturbance of neurodevelopment in progenies has been shown in large case-control studies. These findings suggest that maternal T₄ deficiency in early pregnancy potentially affects neurointellectual development. On the other hand, no apparent adverse effect in children born to mothers with overt hypothyroidism in Japan has been reported where maternal T₄ had been restored to normal by late pregnancy.