In our research we have evaluated the effects produced by obstetric psycho-prophylaxis on women previously prepared by us. To carry out this research we used a method of pain evaluation, quickly and easily administered: Vaona algometer, based on the association between the visual analogue and the scale of greys. The results of the research allow us to confirm that the RAT method, applied during labour, thanks to the positive influence on neuromuscolar relaxation and the psychological aspects of the women, induces a favourable modulation on the perception of pain.