Thyroid Autoantibodies and Excess Risk for Miscarriage and Preterm Birth

The presence of thyroid autoantibodies is relatively common in women of reproductive age, even among those with normal thyroid function. To estimate the association between these autoantibodies and risk for miscarriage or preterm birth, researchers conducted a systematic review and meta-analysis of 19 cohort studies and 12 case-control studies that involved more than 12,000 women.

Thyroid autoantibodies were associated with excess risk for miscarriage (odds ratio, 3.9; P<0.001) and preterm birth (OR, 2.1; P=0.01). Although miscarriage rates generally rise as women age, the observed excess in miscarriage rates among women with thyroid autoantibodies was not explained by differences in maternal age. Pooled analysis of two randomized trials tha…