1. Faculdade de Ciências Aplicadas, Universidade de Campinas, UNICAMP, Limeira 13484-350, São Paulo, Brazil
2. Lundquist Institute at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
3. Department of Obstetrics and Gynecology, David Geffen School of Medicine, University of California Los Angeles at Harbor-UCLA, Torrance, CA 90502, USA
4. Ana Abrao Breastfeeding Center, Escola Paulista de Enfermagem, Universidade Federal São Paulo, UNIFESP, São Paulo 04037-001, São Paulo, Brazil