1. Departments of Public Health Sciences and Obstetrics and Gynecology, College of Medicine, Penn State University, Hershey, Pennsylvania.
2. Department of Health Promotion and Policy, School of Public Health and Health Sciences, University of Massachusetts Amherst, Amherst, Massachusetts.
3. William F. Connell School of Nursing, Boston College, Chestnut Hill, Massachusetts.
4. Department of Obstetrics and Gynecology, Penn State University, Milton S. Hershey Medical Center, Hershey, Pennsylvania.