1. Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota, USA.
2. Division of Pharmacotherapy and Experimental Therapeutics, School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
3. Department of Obstetrics and Gynecology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
4. UNC Project Malawi, Lilongwe, Malawi.
5. Department of Obstetrics and Gynecology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
6. Division of Reproductive Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.