ABSTRACT: Background:Health researchers and provider groups have recommended that women in labor should receive continuous professional support. The objective of our study was to compare the risks and benefits of one-to-one nurse labor support with usual intrapartum nursing care. Methods: A randomized, controlled trial was conducted in a 637-bed university hospital in Montreal, Quebec, with 413 nulliparous women who were at more than 37 weeks' gestation, carrying singletons, and in labor. Women with scheduled cesarean section, scheduled induction, breech presentation, presence of paid labor support, or cervical dilatation over 4 cm were excluded. One-to-one care consisted of the presence of a nurse during labor and birth who provided emotional support, physical comfort, and instruction for relaxation and coping techniques. Usual care consisted of care for two or three laboring women with various types of supportive activities, Results: A beneficial trend due to one-to-one nurse support was found with a 17 percent reduction in risk of oxytocin stimulation (relative risk of experimental vs control = 0.83; 95% confidence interval = 0.67, 1.04). No significant differences were found in overall labor durations and overall rates of total cesarean section, cesarean section for cephalopelvic disproportion, epidural analgesia, admission to the neonatal intensive care unit, instrumental vaginal delivery, and perineal trauma. Conclusions: The beneficial trend attributed to one-to-one nursing in reduction of oxytocin stimulation suggests that implementation of recommendations for continuous professional support by intrapartum nursing staff may be appropriate in North America.