[1] Princeton Univ, Off Populat Res, Woodrow Wilson Sch Publ & Int Affairs, Princeton, NJ 08544 USA
[2] Ibis Reprod Hlth, Cambridge, MA USA
[3] Univ Calif San Francisco, Ctr Reprod Hlth Res & Policy, San Francisco, CA 94143 USA
[4] Family Hlth Int, Biomed Affairs Div, Res Triangle Pk, NC 27709 USA
[5] Univ Michigan, Ctr Populat Studies, Ann Arbor, MI 48109 USA