作者单位:Maternal-Infant Care (MiCare) Research Centre, Mount Sinai Hospital, 700 University Avenue, Toronto[1]University of Toronto, Toronto, ON, Canada[2]University of Alberta, Edmonton, AB, Canada[3]Perinatal Epidemiology Research Unit, IWK Health Centre and Dalhousie University, Halifax, NS[4]University of Saskatchewan, Saskatoon, SK, Canada[5]University of Manitoba, Winnipeg, MB, Canada[6]