[1] Univ Calif Berkeley, Sch Publ Hlth, Div Epidemiol, Berkeley, CA 94720 USA
[2] Publ Hlth Res Inst, Mysore 570020, Karnataka, India
[3] CSI Holdsworth Mem Hosp, Dept Obstet & Gynecol, Mysore 570021, Karnataka, India
[4] Vikram Hosp, Mysore 570020, Karnataka, India
[5] Univ Calif San Francisco, San Francisco, CA 94143 USA