1. Department of Health Promotion and Policy, School of Public Health and Health Sciences, University of Massachusetts Amherst, Amherst, Massachusetts, USA.
2. Cooley Dickinson ObGyn and Midwifery, Cooley Dickinson Medical Group, Northampton, Massachusetts, USA.
3. Department of Public Health Sciences, Penn State College of Medicine, Hershey, Pennsylvania, USA.
4. Department of Obstetrics and Gynecology, Penn State College of Medicine, Hershey, Pennsylvania, USA.