Risk of spontaneous miscarriage in euthyroid women with thyroid autoimmunity undergoing IVF: a meta-analysis

OBJECTIVE: To investigate whether thyroid autoimmunity (TAI) is associated with increased risk for spontaneous miscarriage in subfertile, euthyroid women undergoing IVF. DESIGN: Meta-analysis of observational studies. PATIENT(S): Four prospective studies that reported data on 1098 subfertile women undergoing IVF (141 with TAI and 957 controls) were included in the meta-analysis. MAIN OUTCOME MEASURE: Miscarriage risk ratio (RR). SECONDARY OUTCOME MEASURES: Clinical pregnancy rate and delivery rate. RESULT(S): Euthyroid, subfertile women with TAI undergoing IVF demonstrated significantly higher risk for miscarriage compared with controls (four studies-fixed effects RR: 1.99, 95% confidence interval: 1.42- 2.79, P<0.001). No significant difference in clinical pregnancy and delivery rates was detected between groups. CONCLUSION: Based on the currently available evidence, it appears that the presence of TAI is associated with an increased risk for spontaneous miscarriage in subfertile women achieving a pregnancy through an IVF procedure.