Progression of the first stage of spontaneous labour: a prospective cohort study in two sub-Saharan African countries - Oladapo, Olufemi T.; Souza, João Paulo Dias de; Fawole, Bukola; Mugerwa, Kidza; Perdoná, Gleici da Silva Castro; Alves, Domingos; Souza, Hayala Cristina Cavenague de; Reis, Rodrigo; Ciabati, Lívia Maria de Oliveira; Maiorano, Alexandre C. (PLOS Medicine, 2018)