Objective: To investigate the effects of thyroid stimulating hormone (TSH) and thyroid peroxidase antibody(TPOAb) on pregnancy outcomes of in vitro fertilization-embryo transfer (IVF-ET). Methods: The patients who underwent IVF-ET at the Reproductive Medicine Center of Hefei Maternal and Child Health Care Hospital from December 2019 to November 2023, and had normal free thyroxine and 0.3-<10 mIU/L TSH levels were selected as subjects. The patients were divided into three groups based on TSH levels: 0.3-<2.5 mIU/L, 2.5-4 mIU/L, and >4-<10 mIU/L, and the patients with normal free thyroxine and TSH levels were further divided into TPOAb-positive and TPOAb-negative groups. The biochemical pregnancy rate, clinical pregnancy rate and miscarriage rate were compared among patients with different TSH and TPOAb groups. Results: A total of 3 876 patients were recruited, including 830 patients with fresh embryo transfer cycles and 3 046 patients with frozen-thawed embryo transfer cycles. In the patients with fresh embryo transfer cycles, the biochemical pregnancy rate, clinical pregnancy rate and miscarriage rate were 59.16%, 52.77% and 19.41%, respectively. In the patients with frozen-thawed embryo transfer cycles, these rates were 55.52%, 46.98% and 20.27%, respectively. For both groups, there were no statistically significant differences in biochemical pregnancy rate, clinical pregnancy rate and miscarriage rate between TPOAb-positive and TPOAb-negative patients or among the patients with different TSH groups (all P>0.05). Additionally, a follow-up study of 150 patients who had successfully delivered after IVF-ET from 2020 to 2022 with TSH levels of >4-<10 mIU/L showed that no intellectual developmental issues or tendencies toward intellectual developmental disorders were found in their offsprings. Conclusion In the context of normal free thyroxine levels, this study did not find any impacts of mildly elevated TSH levels or isolated TPOAb positivity on the pregnancy outcomes of IVF-ET.