Associations between thyroid hormones and sperm parameters in men undergoing fertility consultation

Although limited by its retrospective design, which could affect causal inference between THs and sperm parameters, this study demonstrated that TH levels, particularly FT3, showed significant associations with sperm motility and morphology, even within the euthyroid range. Furthermore, TAI status may potentially modulate TH effects on semen quality by some unidentified mechanisms. These findings supported that thyroid function screening should be provided for men with infertility and could help guide personalized endocrine interventions.