Abstract
BACKGROUND: Maternal thyroid autoimmune condition on reproductive health is a topic worthy of attention. Current studies of different groups have produced conflicting results regarding the precise relationship between thyroid autoimmunity (TAI) and IVF/ICSI outcomes. METHODS: A retrospective cohort study included 3197 infertile euthyroid women undergoing their first fresh cycle of IVF/ICSI in our center between January 2015 to May 2024. Participants were split into two groups: the TAI group (n = 965) and the control group (n = 2232) based on the thyroid autoantibody status. Adjusted multivariate logistic regression models were employed to assess the association between TAI and embryo quality as well as pregnancy outcomes. The subgroup and stratified analyses were performed to evaluate the role of thyroid autoantibody types and titers. The subgroup analysis was conducted based on serum TSH levels and ovarian response. RESULTS: The TAI was negatively related to embryos with two-pronucleus (2PN), available cleavage embryos, and high-quality cleavage embryos, no matter which type of thyroid autoantibody is positive. Stratification analysis of thyroid autoantibody titers showed the association was greater as the thyroglobulin antibodies (TGAb) and thyroid peroxidase antibodies (TPOAb) titers increased, respectively. The subgroup analysis showed that TAI patients with high normal thyroid stimulating hormone (TSH) levels (≥ 2.5uIU/mL) and poor ovarian response (POR) were more likely to have fewer 2PN embryos, available cleavage embryos, and high-quality cleavage embryos. However, no association between TAI and pregnancy outcomes was found in all models. CONCLUSION: This study provides comprehensive evidence for the adverse effects of TAI on embryo quality during IVF/ICSI. It is necessary to closely monitor the thyroid hormones and autoantibody levels during treatment, especially in TAI women with TSH ≥ 2.5 uIU/mL and POR.