1 Center for Clinical Epidemiology, Jewish General Hospital, Montreal, Quebec, Canada; Department of Obstetrics and Gynecology, Jewish General Hospital, McGill University, Montreal, Quebec, Canada. Electronic address: haim.abenhaim@gmail.com.
2 Department of Obstetrics and Gynecology, Royal Victoria Hospital, McGill University, Montreal, Quebec, Canada.
3 Center for Clinical Epidemiology, Jewish General Hospital, Montreal, Quebec, Canada.