[1] Univ North Carolina Chapel Hill, Dept Obstet & Gynecol, Chapel Hill, NC USA
[2] UNC Project Malawi, Lilongwe, Malawi
[3] Univ North Carolina Chapel Hill, Dept Epidemiol, Chapel Hill, NC USA
[4] Univ North Carolina Chapel Hill, UNC Ctr AIDS Res, Chapel Hill, NC USA
[5] Univ Michigan, Dept Hlth Behav & Hlth Educ, Ann Arbor, MI USA
[6] Univ North Carolina Chapel Hill, Dept Hlth Behav, Chapel Hill, NC USA
[7] Univ Zambia, Dept Populat Studies & Global Hlth, Lusaka, Zambia
[8] Ctr Int Hlth Educ & Biosecur, Lilongwe, Malawi
[9] Partners Hope, Lilongwe, Malawi
[10] Univ Zambia, Dept Hlth Policy & Syst, Lusaka, Zambia
[11] Univ North Carolina Chapel Hill, 335 S Columbia St CB 7577, Chapel Hill, NC 27599 USA