Received March 24, 2025
Accepted November 25, 2025

Objective: To evaluate the association between antithyroid antibodies detectability and positivity and ovarian reserve. Additionally, we aimed to evaluate the correlation between TSH levels and parameters of ovarian reserve [anti-Mullerian (AMH) levels and antral follicle count (AFC)]. Subjects were women seeking assisted reproductive therapy and oocyte cryopreservation. Methods: AMH, AFC and antithyroid antibodies. In a subgroup of patients, antithyroid antibodies were stratified into categories for the association analyses. The reference values were as follows: antithyroid peroxidase (TPO-Ab): undetectable (< 9 IU/mL), low detectable (9−21 IU/mL), high detectable (22−34 IU/mL), and positive (> 34 IU/mL); antithyroglobulin (Tg-Ab): undetectable (< 10 IU/mL), low detectable (10-60 IU/mL ), high detectable (61-115 IU/mL), and positive (> 115 IU/mL). AMH levels < 1.1 ng/mL and/or AFC < 7 follicles were considered to indicate low ovarian reserve. Results: A total of 453 patients were enrolled. 24.4% had at least one positive antithyroid antibody. Low detectable values for TPO-Ab and Tg-Ab were found in 42.3% and 66.9%, respectively. TPO-Ab and Tg−Ab levels were not statistically different between women with AMH < or ≥ 1,1 ng/mL; there was also no statistically significant difference between antithyroid antibodies levels and AFC < or ≥ 7 follicles. AMH levels did not show significant association with detectability nor positivity of the antithyroid antibodies. No statistically significant correlation was observed between AMH and TSH nor AFC and TSH. Conclusion: Although the detectability of TPO-Ab has been associated with different outcomes, TPO-Ab and/or Tg-Ab were not associated with ovarian reserve in our study.