Impaired central sensitivity to triiodothyronine is associated with gestational diabetes mellitus

Thyroid hormones play an important role in the regulation of glucose metabolism. Recently, some studies determined the relationship between diabetes and abnormality of indices of thyroid hormone sensitivity. Thyroid dysfunction may play a role in the etiology of gestational diabetes mellitus (GDM).

In the present study, we aim to determine central and peripheral thyroid hormone resistance by evaluating indices of thyroid hormone sensitivity and thyroid function tests and to investigate its effect on the etiology of GDM.

A total of 1416 euthyroid pregnant women were included in this study. Of these, 241 (17%) had GDM and 1175 (83%) did not have GDM. We evaluated the association of indices of sensitivity to thyroid hormones including TFQI_FT4, TFQI_FT3, TSHI, TT4RI, and FT3/FT4, with GDM in pregnant euthyroid women.

We found higher FT3, TFQI_FT3, and FT3/FT4 ratio in the GDM group. The present study also showed that significantly increased FT3 and TFQI_FT3 levels were associated with a higher risk of GDM after adjustment for potential confounding factors such as age and body mass index (BMI).

FT3 and TFQI_FT3 were independently associated with the risk of GDM. The results of the present study may shed light on future studies by providing new information on the association of FT3 at the first antenatal visit with GDM.