Newborn weights affected by environmental contaminants

http://www.eurekalert.org/pub_releases/2009-06/uom-nwa061509.php

Public release date: 15-Jun-2009
Contact: Nicole Saint-Pierre
University of Montreal

New study from Sainte-Justine University Hospital Research Center, University of Montreal, McGill University and Public Health Agency of Canada

This release is available in French.

Montreal, June 15, 2009 – Recent epidemiological studies have revealed an increase in the frequency of genital malformations in male newborns (e.g., un-descended testes) and a decrease in male fertility.

The role played by the growing presence in our environment of contaminants that reduce male hormone action could explain this phenomenon.

It is known that the birth weight of males is higher than that of females due to the action of male hormones on the male fetus.If the exposure of pregnant women to environmental contaminants that diminish the action of male hormones has increased over the years, one would expect to see a decrease in the sex difference in birth weight.

This is exactly what a new study published in the July 2009 issue of Epidemiology shows. Investigators analyzed the Public Health Agency of Canada's database on the birth weights of more than five million children born in Canada between 1981 and 2003.