Thyroid autoimmunity in patients with recurrent spontaneous miscarriages.

Recurrent spontaneous miscarriage (RSM) is a multifactorial problem. Auto- and alloimmune parameters have been implicated. Antithyroid antibodies (ATA) were tested in a group of women with RSM. The presence of antipaternal antibodies (APCA) was evaluated as an index of alloimmune contribution. Thirty euthyroid women with RSM (three or more consecutive miscarriages) aged 25-37 years were compared with 15 matched controls. Thyroid peroxidase (TPO) and thyroglobulin antibodies were tested with a chemiluminescence immunoassay and APCA were tested with a cross-match reaction. Results were compared using the chi-squared test. There was a higher frequency of ATA in women with RSM compared to controls (37% versus 13%, p < 0.05). Twenty of the women (67%) with RSM were tested negative for APCA, indicating an alloimmune contribution to their infertility. In this subgroup of women, the frequency of ATA continued to be higher than controls (40% versus 13%, p < 0.05). In conclusion, women with RSM, independent of APCA status, have a higher frequency of ATA. This may represent an additional marker for impaired regulation of the maternal immune system.