Does the presence of thyroid antibodies affect the course and outcome of pregnancy in type 1 diabetic women?

Objective: The aim of the study was to evaluate the significance of the presence of thyroid peroxidase autoantibodies (anti-TPO Abs) in type 1 diabetes mellitus (DM1) pregnant women relative to the course of pregnancy and, especially, with regard to metabolic control, thyroid function, maternal complications and neonatal outcome.

Methods: In a prospective observational study of 91 DM1 women with singleton pregnancies, anti-TPO, anti-thyroglobulin, thyroid-stimulating hormone (TSH), and free thyroxine index (T4/thyroid binding capacity) were measured in each trimester. At each visit, HbA1c, body mass index, and units of insulin per kilogram were recorded, as were complications and pregnancy outcome.

Results: Twenty-one (27%) of the 78 women who met the inclusion criteria presented with positive anti-TPO Abs. There were no differences regarding glycemic control (HbA1c) or insulin dose. First-trimester TSH levels were significantly higher in the anti-TPO-positive group than in the anti-TPO-negative group. Finally, no differences were observed regarding diabetic or obstetric complications and neonatal outcome.

Conclusion: One fourth of DM1 pregnant women presented with positive anti-TPO Abs. However, the presence of anti-TPO Abs does not seem to be related with worse metabolic control or adverse pregnancy outcome. Further investigation is needed; meanwhile, the effort for early treatment of thyroid dysfunction and strict metabolic control in all DM1 women should be continued.