Perineal trauma in a low-risk maternity with high prevalence of upright position during the second stage of labor - Peppe, Mariana Vitor; Stefanello, Juliana; Infante, Bruna Fregonesi; Kobayashi, Mauricio Tsuguio; Baraldi, Claudia de Oliveira; Brito, Luiz Gustavo Oliveira (Revista Brasileira de Ginecologia e Obstetrícia, 2018)