A normal serum total or free T4 concentration and a high serum TSH concentration define subclinical hypothyroidism.

In cases where the serum TSH is marginally elevated (eg, 6 to 10 mU/L), one option is to monitor carefully, repeating a serum TSH and free T4 in a week. Some infants will normalize TSH without treatment using this approach.

However, if the serum TSH does not normalize by four to six weeks of age, we recommend starting thyroid hormone treatment, because of the critical dependence of the developing central nervous system on adequate amounts of T4. high low asymmetrical wedding selections