[1] WHO, Dept Reprod Hlth & Res, CH-1211 Geneva 27, Switzerland
[2] FHI 360, Durham, NC 27713 USA
[3] Univ N Carolina, Dept Maternal & Child Hlth, Gillings Sch Global Publ Hlth, Chapel Hill, NC 27599 USA
[4] Pathfinder Int, Adolescent Sexual & Reprod Hlth, Watertown, MA 02472 USA