Pregnancy, gestational diabetes, thyroid function: our experience

This is a retrospective study of 112 patients with GDM. The purpose is to evaluate the relationship between GDM and impaired thyroid function. All the patients were evaluated: TSH, FT4 and glycosylated hemoglobin (HbA1c). The normal range for TSH is between 0,45 and 2,5 μU/ml; for FT4 is instead between 0,9 and 1,8 ng/dl; for HbA1c is less than 6%. Patients with elevated TSH and low levels of free thyroxine were diagnosed as "hypothyroid"; those with elevated TSH and FT4 in the standard as "subclinical hypothyroid"; pregnant women who had high TSH and low FT4 were diagnosed as "hyperthyroid"; women with low TSH and normal FT4 as "subclinical hyperthyroid". Patients who had normal levels of both thyrotropin and free thyroxine were considered "euthyroid". Based on the values of TSH and FT4 we obtained the following results: 77 patients (68.75%) euthyroid; 18 (16.1%) subclinical hypothyroidism; 12 (10.7%) hypothyroid; 5 patients (4.4%) subclinical hyperthyroidism. Our study confirms the association between thyroid disease and gestational diabetes. In addition, the hypothyroid patients insulin-treated, compared with euthyroid, increased the insulin requirement. The results show that women with GDM have a risk greater for both clinical and subclinical hypothyroidism; for this reason it is advisable to carry out a program of screening for thyroid function.