Zung A, et al. - In this observational study involving 113 children, researchers evaluated the clinical and neurological results in newborns with primary congenital hypothyroidism presented with delayed TSH elevation (dTSH; defined as elevated TSH in the second neonatal screening after normal TSH in the initial screening), and defined parameters that can predict the evolution of transient vs permanent hypothyroidism in these newborns. Between newborns with spontaneous recovery and children with a final diagnosis of either transient or permanent hypothyroidism, birth parameters, thyroid screening results, thyroid gland imaging, levothyroxine dose, and neurological outcome were contrasted. Of the children with a history of dTSH, 93% showed recovery, either spontaneously or following levothyroxine treatment (transient hypothyroidism). Newborns with spontaneous recovery showed milder thyroid dysfunction at the newborn screening vs those who began levothyroxine treatment. In most cases of dTSH, thyroid dysfunction is transient. No accurate parameters can predict a priori transient compared with permanent hypothyroidism.