[1] WHO, Dept Maternal Newborn Child & Adolescent Hlth, CH-1211 Geneva, Switzerland
[2] WHO, Dept Mental Hlth & Subst Abuse, 20 Ave Appia, CH-1211 Geneva 27, Switzerland
[3] WHO, Pan Amer Hlth Org, Ctr Perinatol Women & Reprod Hlth, Montevideo, Uruguay
[4] WHO, Dept Reprod Hlth & Res, CH-1211 Geneva, Switzerland
[5] WHO, Dept Pandem & Epidem Dis, CH-1211 Geneva, Switzerland
[6] WHO, Reg Off Europe, Div Communicable Dis & Hlth Secur, DK-2100 Copenhagen, Denmark
[7] WHO, Dept Communicable Dis & Hlth Anal, Pan Amer Hlth Org, Washington, DC USA