title: Authors' reply to Thilagnathan.
authors.affiliation: Departments of Medicine, Health Policy Management and Evaluation, and Obstetrics and Gynecology, St Michael's Hospital, University of Toronto, Toronto, Canada.
authors.forename: Joel G
authors.initials: JG
authors.lastname: Ray
authors.affiliation: University of Toronto, Toronto, Canada.
authors.forename: Emily
authors.initials: E
authors.lastname: Bartsch