1 Department of Gynecology and Obstetrics, Department of Population, Family, and Reproductive Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA, Johns Hopkins Bayview, 4940 Eastern Ave, A-101, Baltimore, MD 21224, USA. Electronic address: aburke@jhmi.edu.
2 Department of Obstetrics and Gynecology, University of Zimbabwe, Harare, Zimbabwe.