INTRODUCTION: Maternal position plays an essential role in achieving labour progress as it supports the physiological mechanisms of labour. Evidence supports that adopting upright positions may facilitate physiological childbirth. AIM: To describe the use of various positionsamong nulliparous pregnant women in the last 24 h before birth and describe physical positions in relation to maternal and neonatal outcomes at time of birth. METHODS: Cohort study of 105 nulliparous women with an uncomplicated singleton pregnancy. Body position was measured by two triaxial accelerometers (SENS motion®), and maternal and neonatal outcomes at time of birth were obtained from medical records. Positions were described for the total population and further stratified into two groups based on time spent in sacrum non-flexible (lying, sitting) and sacrum flexible (standing, walking) positions.Descriptive analyses of maternal position in relation to birth outcomes and comparisons between the two groups were made. RESULTS: Lying down was the mostfrequent position adapted, with a median time of 659 (78
1208) minutes, equivalent to 11.0 hours. Women spent 1152 (687
1369) minutes in sacrum non-flexible positions, equivalent to 19.2 hours or 80 % of the last 24 hours before childbirth. More than 90 % gave birth in a sacrum non-flexible position. Women spending more time in sacrum non-flexible positions had more epidural analgesia than women spending more time in sacrum flexible positions (42.6 % and 21.3 %, p = 0.03). CONCLUSIONS: Women spent 80% of their time in sacrum non-flexible positions during the last 24 hours before childbirth. At birth, more than 90% gave birth in sacrum non-flexible positions.