1. Department of Obstetrics, Hospital Maternidade Escola de Vila Nova Cachoeirinha, São Paulo, SP, Brazil
2. Department of Obstetrics and Gynecology, Faculty of Medicine, Pontifícia Universidade Católica de São Paulo, São Paulo, SP, Brazil
3. Department of Obstetrics, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil