1. National University of Colombia; Department of Obstetrics & Gynecology and Clinical Research Institute, Faculty of Medicine; Carrera 30 No. 45-03 Bogota Colombia
2. Free time independent Cochrane reviewer; 7838 Heatherton Lane Potomac USA 20854
3. University of Auckland; Department of Obstetrics and Gynaecology; FMHS Park Road Grafton Auckland New Zealand 1003
4. Ecole des Hautes Etudes en Santé Publique; Paris France