Analgesia during labor and vaginal birth among women with severe maternal morbidity: secondary analysis from the WHO multicountry survey on maternal and newborn health - Souza, Marcio A.; Guida, Jose P. S.; Cecatti, José Guilherme; Souza, João Paulo Dias de; Gülmezoglu, Ahmet Metin; Betran, Ana Pilar; Torloni, Maria R.; Vogel, Joshua P.; Costa, Maria Laura (BioMed Research International, 2019)