1 Department of Obstetrics and Gynecology, Western Michigan University, Homer Stryker MD School of Medicine, 1000 Oakland Drive, Kalamazoo, MI 49008, USA. Electronic address: kevin.ault@med.wmich.edu.
2 Division of Maternal-Fetal Medicine, Department of Obstetrics & Gynecology, University of Washington, 1959 NE Pacific Street, Box 356460, Seattle, WA 98195, USA. Electronic address: abk26@uw.edu.