RESUMEN
To determine the thyroid status of mothers of newborns with primary congenital hypothyroidism. Thyroid function tests were carried out on 80 mothers of hypothyroid newborns and 80 mothers of non-hypothyroid newborns as control. The mean difference of the tests revealed that mothers of congenitally hypothyroid infants had a lower triiodothyronine resin uptake [T3RU] concentrations compared with the control population. The higher value of free thyroxin index [FTI] in case group showed a tendency to significance. The proportional frequency distribution showed; T3RU and triiodothyronine [T3] had a significant difference, and FTI showed a tendency to significance. There were no significant differences between; thyroid-stimulating hormone [TSH], thyroxine [T4] and anti-thyroid peroxidase antibodies [anti-TPO] in two groups. These results indicated that at least some cases of primary congenital hypothyroidism were attributable to the maternal thyroid disease. Therefore, we recommend that each pregnant woman should be assessed for thyroid function in region with a high prevalence of thyroid disease