1. The University of Liverpool; Cochrane Pregnancy and Childbirth Group, Department of Women's and Children's Health; First Floor, Liverpool Women's NHS Foundation Trust Crown Street Liverpool UK L8 7SS
2. Centro Rosarino de Estudios Perinatales (CREP); Moreno 878 piso 6 Rosario Santa Fe Argentina 2000
3. Nottingham Health Science Partners; Nottingham Clinical Trials Unit; C Floor, South Block Queen's Medical Centre Nottingham UK NG7 2UH
4. Division of Health Sciences, Warwick Medical School, The University of Warwick; Warwick Clinical Trials Unit; Gibbet Hill Road Coventry UK CV4 7AL
5. World Health Organization; UNDP/UNFPA/UNICEF/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP), Department of Reproductive Health and Research; 20 Avenue Appia Geneva Switzerland 1211
6. Parkview Tower, 5th Floor Ras Beirut Lebanon
7. London School of Hygiene and Tropical Medicine; Medical Statistics Department; London UK