The pain experimented by women during the labor is considered as one of the most important, significative and stressing events in the life of a woman. It is widely known than labour is the caused of severe pain. Our purpose is to review the aspects related to the experience of acute pain of patients in labor, related to the normal physiology in this process and to describe different variables that can modify it. From the evidence we conclude that perception of pain is subjective and variable, and it is influenced or modified for multiple factors, by past living experiences or transmitted through generations, by socio-cultural environment and individual expectative in front of this event, also by psychological, clinical, biochemical and genetic factors that predispose to experience a different perception of its severity. This information seems relevant to us for a better comprehension of pain during the labor and for developing strategies that would allowed a relief in a more effective way helping the maternal-fetal welfare and a better experience of maternity, especially during labor.