1. Department of Obstetrics and Gynecology, School of Medical Sciences, University of Campinas, Campinas, Brazil
2. Department of Social Medicine, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
3. The UNDP/UNFPA/UNICEF/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction, Department of Reproductive Health and Research, World Health Organization, Geneva, Switzerland
4. Federal University of Sao Paulo, Sao Paulo, Brazil
5. Maternal and Child Health Program, Burnet Institute, Melbourne, Australia