1. Department of Obstetrics and Gynecology, School of Medicine, Washington University in St Louis, St Louis, Missouri
2. Department of Obstetrics and Gynecology, Perelman School of Medicine, Maternal and Child Health Research Center, University of Pennsylvania, Philadelphia
3. Department of Obstetrics and Gynecology, University of Alabama, Birmingham
4. Center for Women’s Reproductive Health, University of Alabama, Birmingham
5. Department of Obstetrics and Gynecology, Oregon Health & Science University, Portland
6. Division of Public Health Sciences, School of Medicine, Washington University in St Louis, St Louis, Missouri
7. Department of Pediatrics, School of Medicine, Washington University in St Louis, St Louis, Missouri