[1] Hlth Canada, Populat Studies Div, Hlth Environm & Consumer Safety Branch, 50 Colombine Dr,AL 0801A, Ottawa, ON K1A 0K9, Canada
[2] INSPQ, CTQ, Quebec City, PQ, Canada
[3] Harvard Univ, Sch Publ Hlth, Dept Environm Hlth & Epidemiol, 665 Huntington Ave, Boston, MA 02115 USA
[4] Hlth Canada, Hlth Prod & Food Branch, Bur Chem Safety, Ottawa, ON K1A 0L2, Canada
[5] CHU Quebec, Ctr Rech, Axe Sante Populat & Prat Optimales Sante, Quebec City, PQ, Canada
[6] Ottawa Hosp, Res Inst, Clin Epidemiol Program, Ottawa, ON, Canada
[7] Univ Ottawa, Dept Obstet & Gynecol, Ottawa, ON, Canada
[8] Ottawa Hosp, Dept Obstet & Perinatal Med, Ottawa, ON, Canada