Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among reproductive-aged women. Follicular uid quality affects early embryonic development and multiple stages of pregnancy. This study measured 12 elements in follicular uid and 5 blood hormones, aiming to identify the associations between multielement concentrations, as well as blood hormone levels, and PCOS to investigate the interference of multielement coexposure on PCOS and examine the potential roles of hormones. Eight elements (As, Cu, Se, Sr, V, Zn, Cr, Ca), but not Mg, showed a positive dose-effect relationship with PCOS. The OPLS models of follicle-stimulating hormone (FSH) and anti-Müllerian hormone (AMH) with relevant elements showed that Mg, Zn, Fe, Se and V had a more signi cant effect on FSH and that As, Se, V, Cu and Zn were positively correlated with AMH (VIP > 1). Further analysis indicated a synergistic effect for FSH and Mg, both of which were protective factors against PCOS; the associations between the ve elements and PCOS incidence were mediated by AMH. Changes in hormone levels between multielement coexposure and PCOS development suggest that FSH and Mg are protective against PCOS; female exposure to As, Se, V, Cu, and Zn may affect PCOS progression by perturbing AMH levels. c p values of all parameters were obtained by non-parametric Mann-Whitney U test. * indicates p < 0.05, ** indicates p < 0.01.d IVF: In Vitro Fertilization e ICSI: Intracytoplasmic sperm injection

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among reproductive-aged women. Follicular fluid quality affects early embryonic development and multiple stages of pregnancy. This study measured 12 elements in follicular fluid and 5 blood hormones, aiming to identify the associations between multielement concentrations, as well as blood hormone levels, and PCOS to investigate the interference of multielement coexposure on PCOS and examine the potential roles of hormones. Eight elements (As, Cu, Se, Sr, V, Zn, Cr, Ca), but not Mg, showed a positive dose–effect relationship with PCOS. The OPLS models of follicle-stimulating hormone (FSH) and anti-Müllerian hormone (AMH) with relevant elements showed that Mg, Zn, Fe, Se and V had a more significant effect on FSH and that As, Se, V, Cu and Zn were positively correlated with AMH (VIP > 1). Further analysis indicated a synergistic effect for FSH and Mg, both of which were protective factors against PCOS; the associations between the five elements and PCOS incidence were mediated by AMH. Changes in hormone levels between multielement coexposure and PCOS development suggest that FSH and Mg are protective against PCOS; female exposure to As, Se, V, Cu, and Zn may affect PCOS progression by perturbing AMH levels.