The study, published in the Journal of Clinical Investigation, found female mice injected under the skin with polycyclic aromatic hydrocarbons before pregnancy or while lactating were found to have normal-sized litters but their female offspring had markedly reduced numbers of follicles -- cell clusters that each contain an egg.

The University of Toronto researchers led by Andrea Jurisicova further found that the effect of polycyclic aromatic hydrocarbons on the number of follicles was mediated through the aryl hydrocarbon receptor.

The potential importance of these findings for women of child-bearing age was demonstrated by the observation that polycyclic aromatic hydrocarbons triggered similar molecular pathways in human ovarian tissue transplanted into immunocompromised mice, Jurisicova said.