There is scientific evidence indicating that various features of labor (uterine contractions, labor progression, maternal comfort, fetal condition) may be affected by the maternal position [3,14,39,47,53,59,60,66,70,84,89,92]. Custom has greatly influenced our present obstetrical care, perhaps more than our scientific knowledge [5,12,40,26,49,52,58,68,71,73,78,79,85,87]. This paper intends to review some of the factors that determined our traditions in this regard and also briefly reviews the recent scientific findings that challenge some of our present routines concerning the obstetrical management of the first stage of labor.