Objective: To compare two low-dose oxytocin protocols in terms of fetal distress, uterine hyperstimulation, cesarean delivery rate, maximum dose of oxytocin, and length of labor.
Methods: We randomized 865 patients into 15-minute (incremental dose 1 mU/minute until 5 mU/minute, then 1 or 2 mU/minute) or 40-minute (incremental dose 1.5 mU/minute until 7 mU/minute, then 1.5 or 3.0 mU/minute) low-dose protocols. Before oxytocin use, all subjects were stratified according to parity and purpose of oxytocin, ie, for induction or augmentation of labor.
Results: The 40-minute dosing protocol had a significantly lower maximum dose of oxytocin (augmentation, 6.5 versus 8.2 mU/minute, P < .001; induction, 11.5 versus 14.5 mU/minute, P < .001), a lower incidence of uterine hyperstimulation (augmentation, 18.8 versus 31.8%, P < .001; induction, 19.1 versus 33.0%, P < .002), and less fetal distress (augmentation, 15.5 versus 26.1%, P < .005). No significant differences were found in the cesarean rate or length of labor.
Conclusion: A dosing interval of 40 minutes led to lower incidences of uterine hyperstimulation and fetal distress, and decreased the maximum dose of oxytocin, without affecting the length of labor or the cesarean rate.