1. Department of Maternal and Child Health, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
2. Carolina Population Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
3. Department of Family Health Care Nursing, University of California, San Francisco, California, USA.
4. Department of Obstetrics and Gynecology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
5. N.C. Women's Hospital, UNC Chapel Hill, North Carolina, USA.
6. Momma's Village of Fayetteville, Fayetteville, North Carolina, USA.