Exposure to heavy metals (lead, cadmium and mercury) and its effect on the outcome of in-vitro fertilization treatment

We investigated the effect of lead, cadmium and mercury exposure on pregnancy and fertilization rate outcome among 619 Saudi women (age 19-50 years) who sought in-vitro fertilization (IVF) treatment between 2002 and 2003. The concentrations of lead, cadmium and mercury were measured in both blood and follicular fluids. At levels well below the current US occupational exposure limit guidelines (40microg/dL) and even less than the current Centers for Disease Control and Prevention level of concern for preventing lead poisoning in children (10microg/dL), blood lead level was negatively associated with fertilization outcome in both adjusted and unadjusted logistic regression models. We found that among various demographic, socioeconomic and environmental factors, fish consumption was positively associated with blood lead levels. These results support the hypothesis that a raised blood lead level affects infertility and intervention to reduce the lead exposure might be needed for women of reproductive age. The present results also revealed unexpected finding - the positive relationship between follicular cadmium levels and fertilization outcome, which points to the necessity for further investigation. Though adverse effect of mercury on pregnancy outcome or fertilization rate was not evident in this study, mercury5.8microg/L (EPA safety limit) was found in the blood and follicular fluid of 18.7% and 8.3% of the women, respectively. Concerns about its possible adverse effects on the physiology of reproduction or fetal development cannot be ruled out. It should be noted that skin-lightening creams and dental amalgam were important contributors to mercury exposure. Such finding is alarming and priority for further studies are, urgently, needed.