Body Burdens of Mercury (Hg), Cadmium (Cd), and Lead (Pb) and Oocyte Fertilization among Women Undergoing a First Cycle of In Vitro Fertilization

ISEE-0188 Background and Objective: Exposures to non-essential trace metals, including Hg, Cd, and Pb, are ubiquitous and threaten reproductive health. This study aims to investigate associations between body burdens of these metals and in vitro oocyte fertilization among a cohort of women undergoing a first IVF treatment cycle. Methods: Between 2006 and 2008, 55 women between 28–44 years of age initiating their first IVF treatment cycle were recruited to and finished the study. Urine specimens were analyzed for Cd using inductively-coupled plasma mass spectrometry (ICP-MS) and corrected for creatinine concentrations. Whole blood specimens from 50 participants were analyzed for total Hg, Cd, and Pb using ICP-MS. The successful fertilization of a mature oocyte (MII) was defined as the presence of two pronuclei 16–18 hours following insemination. Participants contributed a median of 8 oocytes (range 2–39). Multiple logistic regression models were used to evaluate associations between successful fertilization and metals, while adjusting for potential confounders selected using directed acyclic graphs. Generalized estimating equations were used to adjust standard errors for clustering of outcomes by subject. Results: Median blood concentrations for total Hg (4.15 μg/L) exceeded that reported by NHANES for the 2001–2002 female U.S. population (0.70 μg/L); however concentrations for the other metals were comparable. Adjusting for age, cigarette smoking, and ethnicity, there were no statistically significant associations between successful fertilization and blood total Hg (β = 0.05 P = 0.557), Cd (β = 0.82 P = 0.134), or Pb (β = −0.31, P = 0.587), or urine Cd (β = 0.52 P = 0.503). A comprehensive model simultaneously including blood Hg, Cd and Pb, as well as potential confounders produced similar results, as did a model considering only urine Cd and potential confounding variables. Conclusion: These results are not supportive of a deleterious effect for body burdens of Hg, Cd, or Pb received from background sources on oocyte fertilization during first IVF cycles.