Contaminants may affect male newborns

MONTREAL, June 16 (UPI) -- Canadian epidemiologists say they have linked lower male newborn birth weights to an increased frequency of genital malformations.

Lead researcher Dr. Guy Van Vliet of Sainte-Justine University Hospital Research Center in Montreal suggest both decreased male birth weight as well as decreased male fertility are linked to the increased presence of environmental contaminants that may affect male hormone action.

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

That is exactly what the researchers found, Van Vliet said.

The researchers used the Public Health Agency of Canada's database on the birth weights of more than 5 million children born in Canada from 1981-2003.

The study, published in the journal Epidemiology, found a sustained decrease in birth weight between boys and girls.

"Our study underlines the importance of probing the impact of environmental contaminants on the health of mothers and fetuses and on the reproductive potential of future generations," Van Vliet said in a statement.