High levels of mercury in the blood, possibly caused by eating a lot of seafood, are associated with infertility in men and women, researchers have found.
Infertility-mercury link measured
Researchers at the Chinese University of Hong Kong studied mercury levels in 157 infertile couples and 26 fertile couples.
They found that 35% of the men and 23% of the women in the infertile group had abnormally high blood mercury concentrations, compared with 15% of men and 3.8% of women in the fertile group.
Lead researcher Dr Christine Choy and colleagues also compared how much seafood the couples ate and found that patients who reported eating more seafood tended to have higher blood mercury levels.
The sea water around Hong Kong is contaminated with heavy metals, which may be a possible source of excessive mercury exposure, the researchers report in the October issue of the British Journal of Obstetrics and Gynaecology.
The correlation between the quantity of seafood consumed and blood mercury concentrations suggests that higher seafood consumption may contribute to higher blood mercury concentrations, the researchers write.
High infertility rates
The researchers suggest that the mercury might disrupt sperm membrane permeability or motion in men. The link between female fertility and mercury is less clear, although it could cause cellular or genetic damage in the ovaries, the researchers suggest.
Infertility levels in China are high, with about one in six couples affected. Forty percent of infertility cases are linked to men and another 40% are due to female problems.
The researchers suggest cutting back on seafood consumption to avoid high blood mercury levels.