[1] Univ British Columbia, Reprod Endocrinol & Infertil, Vancouver, BC, Canada
[2] Inst Clin Evaluat Sci, Kingston, ON, Canada
[3] Queens Univ, Family Med, Kingston, ON, Canada
[4] Bloomberg Sch Publ Hlth, Populat Family & Reprod Hlth, Baltimore, MD USA
[5] Queens Univ, Dept Obstet & Gynecol, Kingston, ON, Canada