Thyroperoxidase and Thyroglobulin Antibodies in Early Pregnancy and Placental Abruption

OBJECTIVE: To estimate the relationship between thyroid antibodies and placental abruption. METHODS: This cohort study assesses thyroperoxidase and thyroglobulin antibodies in relation to placental abruption among 10,062 women with singleton viable pregnancies (from the First and Second Trimester Risk of Aneuploidy [FaSTER] trial). A thyroperoxidase antibody cutoff of 50 international units/mL is used for comparison with published data from another cohort. RESULTS: Women with elevated thyroperoxidase antibody levels in the first and second trimesters have a higher rate of placental abruption than antibody-negative women. This relationship is less strong in the first trimester (1.51% compared with 0.83%; odds ratio [OR], 1.83; 95% confidence interval [CI], 0.99-3.37) than in the second trimester (1.78% compared with 0.82%; OR, 2.20; 95% CI, 1.21-3.99). A similar, but weaker, relationship is present for thyroglobulin antibodies. Sixty-four of 782 thyroperoxidase antibody-positive pregnancies without abruption become negative by the second trimester; one pregnancy with abruption becomes antibody-positive. Odds ratios for pregnancies with both thyroperoxidase and thyroglobulin antibody elevations are also higher (first trimester: OR, 2.10; 95% CI, 0.91-4.86; second trimester: OR, 2.73; 95% CI, 1.17-6.33). CONCLUSION: The present data confirm an association between thyroid antibody elevations and placental abruption described in a recent report. These findings, however, do not provide support for recommending routine testing for thyroid antibodies during pregnancy. LEVEL OF EVIDENCE: II.