[1] Novametrics, Duffield DE56 4HQ, England
[2] Novametrics, Tacoma, WA USA
[3] Novametrics, Bias, France
[4] World Hlth Org, Dept Maternal Newborn Child & Adolescent Hlth & A, Geneva, Switzerland
[5] United Nations Populat Fund, Uganda Country Off, Kampala, Uganda
[6] United Nations Populat Fund Off Geneva, Geneva, Switzerland
[7] Univ Sydney, Fac Med & Hlth, Sydney, NSW, Australia
[8] Burnet Inst, Maternal Child & Adolescent Hlth, Melbourne, Vic, Australia