Background exposure to toxic metals in women adversely influences pregnancy during in vitro fertilization (IVF).

Low-level environmental exposure to Hg, Pb and Cd may interfere with pregnancy during in vitro fertilization (IVF). The aim of this study was to generate hypotheses concerning associations between background exposures and pregnancy. In modified Poisson regression models including 24 women and adjusted for urine Cd and creatinine, blood Pb, age, race and smoking, 1 μg/L increases in blood Hg are associated with decreases of 35% (P=0.03) and 33% (P=0.01) in clinical and biochemical pregnancies, respectively. In alternate Poisson models including 26 women and adjusted for blood Pb, blood Hg, age, race and smoking, 1 μg/L increases in blood Cd are associated with decreases of 94% (P=0.01) and 82% (P=0.04) in clinical and biochemical pregnancies, respectively. No effects are detected in 15 men, although inverse associations are suggested for urine cadmium and pregnancy. These data suggest that low-level, background exposures to Hg and Cd may interfere with pregnancy following IVF.