1 Society of Obstetricians and Gynaecologists of Canada, Ottawa, ON, Canada; Department of Obstetrics, Gynaecology and Newborn Care, University of Ottawa, Ottawa, ON, Canada. Electronic address: jcook@sogc.com.
2 Maternal Mortality Prevention Team Division of Reproductive Health Centers for Disease Control and Prevention, United States.
3 Oxford Population Health, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom; National Perinatal Epidemiology Unit, University of Oxford, Oxford, United Kingdom.