1. Vanderbilt University School of Nursing, Vanderbilt University, Nashville, TN, USA
2. Vanderbilt Institute for Global Health, Vanderbilt University Medical Center, Nashville, TN, USA
3. Division of Epidemiology and Biostatistics, School of Public Health, University of Cape Town, Cape Town, South Africa
4. Vanderbilt Institute for Spatial Research, Vanderbilt University, Nashville, TN, USA
5. University of California, San Francisco, Department of Obstetrics, Gynecology & Reproductive Sciences, San Francisco, CA, USA