The evaluation of transient hypothyroidism in patients diagnosed with congenital hypothyroidism

Congenital hypothyroidism (CH) is divided into two groups as 'permanent' and 'transient' We aimed to determine the rate of transient and permanent congenital hypothyroidism of the newborns referred to our clinic.

Of the newborns who were referred to our clinic from the neonatal screening program, those who were diagnosed with CH and started treatment were included in the study. The treatments of the patients whose required daily treatment dose was reduced to under 1 µg/kg were terminated and those who were followed monthly and whose fT4 and thyroid-stimulating hormone (TSH) levels were normal at least 3 times without treatment were considered to have transient hypothyroidism.

Of the 256 newborns referred to our clinic from the neonatal screening program, 114 (44.5%) were diagnosed with CH. Of the CH patients, 70% (n = 58) were evaluated to have permanent and 30% (n = 25) transient hypothyroidism. Neonatal and serum TSH levels and treatment doses were found to be significantly lower in the transient hypothyroidism patients.

Initial measurements of the serum TSH level and the required doses of L-thyroxine therapy for maintaining normal thyroid hormone levels, growth, and development may have a predictive role for differentiating permanent forms of CH from transient forms.