Toxic elements in hair and in vitro fertilization outcomes: A prospective cohort study.

We analysed the association between the concentration of four toxic elements (As, Cd, Hg and Pb) and diverse reproductive outcomes in a cohort of 194 women with fertility disorders undergoing IVF in a public hospital. Concentration in hair specimens was explored as biomarker of exposure during the three months prior to oocyte retrieval. The proportion of negative results, especially regarding pregnancy and birth outcomes, is remarkable. However, we found that the probability of mature oocytes was inversely associated with the concentration of Hg in hair (RR = 0.81, 95% CI: 0.70-0.95) and directly associated with that of Pb (RR = 1.18, 95% CI: 1.03-1.35). These findings provide insights for future research on the links between heavy metal concentrations and IVF outcomes.