Is thyroid autoimmunity associated with gestational diabetes mellitus?

Because inflammatory markers have been associated with incident diabetes mellitus, we aimed to evaluate if thyroid peroxidase antibodies (TPOAbs) in early pregnancy are predictive of gestational diabetes mellitus (GDM). Six hundred nineteen pregnant women without former diabetes mellitus were evaluated for TPOAb positivity after booking. A universal GDM screening protocol and the Third Workshop–Conference criteria were used for GDM detection. In addition to bivariate analysis, multivariate logistic regression models were constructed with GDM as the dependent variable and TPOAb positivity as one of the potential predictive ones. The rate of TPOAb positivity was 10%; and that of GDM, 6.9% (6.8% in women without and 8.1% in women with TPOAb positivity, not significant). Thyroid peroxidase antibodies did not enter the multivariate logistic regression model to predict GDM that identified the following independent predictive variables: maternal age (odds ratio [OR] 1.5, 95% confidence interval [CI] 0.57-4.0 for the second tertile; OR 2.84, 95% CI 1.16-6.96 for the third tertile), prior GDM (OR 9.38, 95% CI 3.34-26.39), and diabetes mellitus in first-degree relatives (OR 3.22, 95% CI 1.65-6.27). In conclusion, we have not identified TPOAb positivity in early pregnancy as a predictor of GDM.