1. UNDP/UNFPA/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction, World Health Organization, CH–1211 Geneva 27, Switzerland
2. Centro Rosarino de Estudios Perinatales (CREP), WHO Collaborative Center in Maternal and Child Health, Rosario 2000, Argentina
3. Geneva Foundation for Medical Education and Research, Geneva, Switzerland
4. Department of Nutrition, World Health Organization, CH–1211 Geneva 27, Switzerland