Thyroid autoimmunity and pre-term delivery: brief review and meta-analysis.

ABSTRACT

BACKGROUND: About 10% of women in childbearing age are positive for thyroid antibodies. The presence of such antibodies has been associated with adverse obstetrical outcomes, in particular miscarriage and pre-term delivery, even though the strength of these associations varies widely from one study to another. AIM: To evaluate from the available data of the literature, the association between thyroid autoimmunity and pre-term delivery. MATERIALS AND METHODS: MEDLINE, EMBASE, Cochrane Library search from 1990 to 2010. A combination of key words was used to generate 2 subset of citations, one indexing thyroid antibodies and the other indexing pre-term delivery as adverse outcome. RESULTS: Seven studies, collecting about 23,000 patients were selected. Meta-analysis of the studies showed an association between thyroid autoimmunity and pre-term delivery [odds ratio =1.67 (confidence interval 1.44- 1.94; p<0.001)]. CONCLUSIONS: The results of the meta-analysis confirmed the association between thyroid autoimmunity and pre-term delivery. A cause-effect relationship has to be still clarified and interventional studies are required.