Association between thyroid autoantibodies and miscarriage and preterm birth: meta-analysis of evidence

To evaluate the association between thyroid autoantibodies and miscarriage and preterm birth in women with normal thyroid function. To assess the effect of treatment with levothyroxine on pregnancy outcomes in this group of women.

Systematic review and meta-analysis. DATA SOURCES: Medline, Embase, Cochrane Library, and SCISEARCH (inception-2011) without any language restrictions. We used a combination of key words to generate two subsets of citations, one indexing thyroid autoantibodies and the other indexing the outcomes of miscarriage and preterm birth. STUDY SELECTION: Studies that evaluated the association between thyroid autoantibodies and pregnancy outcomes were selected in a two stage process. Two reviewers selected studies that met the predefined and explicit criteria regarding population, tests, and outcomes. DATA SYNTHESIS: Odds ratios from individual studies were pooled separately for cohort and case-control studies with the random effects model.