1 Department of Obstetrics, Gynecology, and Reproductive Biology, College of Human Medicine, Michigan State University, lukeb@msu.edu Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, Michigan Massachusetts Department of Public Health, Boston, MA Department of Obstetrics & Gynecology, Geisel School of Medicine and, Dartmouth-Hitchcock, Lebanon, NH.