Environmental toxins may limit fertility (11/26/2007)

Mothers who are exposed to certain toxic environmental compounds prior to pregnancy could limit their offspring's fertility, says a new study by researchers at U of T and Mount Sinai Hospital's Samuel Lunenfeld Research Insititute.

The study, published in the Dec. 3 issue of The Journal of Clinical Investigation, provides evidence derived from a mouse model that exposure to the compounds called polycyclic aromatic hydrocarbons (PAHs) prior to conceiving and when lactating reduces the number of eggs in the ovaries of female offspring by two-thirds. PAHs are known carcinogens and one of the most widespread organic pollutants. The compounds are found in cigarette smoke, car exhaust, fumes from wood stoves and in charred and smoked foods.

"The impact of this research is significant," said Professor Jim Woodgett of medical biophysics and Lunenfeld's director of research. "While the anti-smoking message is clear, these findings serve as a preventative measure for all Canadians and should raise awareness of common environmental toxins."

PAHs accumulate in the body's breast and fatty tissues before pregnancy and are later released into the blood during pregnancy, affecting the fetus.

"While young girls and women may not have thought about their reproductive future, exposure to these toxins now may reduce the fertility of their children," said Professor Andrea Jurisicova of obstetrics and gynecology, lead author of the study and Canada Research Chair in Molecular and Reproductive Medicine at the Lunenfeld.

The reduction of eggs in a woman's ovaries can lead to premature menopause which not only limits reproduction but is also associated with osteoporosis, heart disease, stroke and depression.

"This kind of research has important potential implications for future generations. The findings underline the importance of funding and designing cohort and other epidemiologic studies to assess the reproductive and child health effects of exposure to PAHs and other environmental toxins in human populations," said Dr. Michael Kramer, scientific director of the Canadian Institutes for Health Research's Institute of Human Development, Child and Youth.

Note: This story has been adapted from a news release issued by the University of Toronto

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