*School of Public Health, Oregon Health & Science University and Portland State University, Portland, OR

†Center for Health Systems Effectiveness, Oregon Health & Science University, Portland, OR

‡Department of Obstetrics and Gynecology, Oregon Health & Science University, Portland, OR

M.I.R. reported receiving personal fees from the American College of Obstetricians and Gynecologists, Bayer, and Merck & Co. outside the submitted work. The Oregon Health & Science University Institutional Review Board manages these potential conflicts of interest. The remaining authors declare no conflict of interest.

Correspondence to: Menolly Kaufman, PhD, MPH, School of Public Health, Oregon Health & Science University and Portland State University, Center for Health Systems Effectiveness, Oregon Health & Science University, 3181 S.W, Sam Jackson Park Road, MDYCHSE, Portland, OR 97239-3098. E-mail: [email protected].

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