Rocha, B.D. da . et al. 2020. Upright positions in childbirth and the prevention of perineal lacerations: a systematic review and meta-analysis. Revista da Escola de Enfermagem da USP. 54, (Sep. 2020), e03610. DOI:https://doi.org/10.1590/s1980-220x2018027503610 .