High and low dose oxytocin in augmentation of labor. A randomized control study of oxytocin augmentation of labour. 1. Obstetric outcome. Early versus delayed oxytocin augmentation in nulliparous women with prolonged labour--a randomised controlled trial.
To compare the efficacy and safety of high dose oxytocin in the augmentation of labor.
                Two hundred pregnant women requiring augmentation of labor were randomly assigned to receive oxytocin by either a low dose protocol (1.5 microm/min initially, increased by 1.5 microm/min every 30 min) or a high dose protocol (4.5 microm/min initially, increased by 4.5 microm/min every 30 min).
                High dose of oxytocin was associated with a significant shortening of labor 4 (1.10-10) vs. 6 (1-10) h, p<0.0001 without a significant difference in cesarean delivery rate, neonatal and maternal outcome.
                The use of high dose oxytocin is associated with significantly shorter labor without any adverse fetal and maternal effects. Sixty women who were progressing slowly in spontaneous labour were assigned at random to three management protocols. Group 1 were observed without the use of oxytocin for 8 h while groups 2 and 3 were managed with a low-dose and high-dose oxytocin protocol respectively. The caesarean section rates were not significantly different between the three groups: 45%, 35% and 26% respectively. Cervical dilatation rate increased significantly after oxytocin infusion in both treatment groups compared with controls. The 'delay-to-delivery' interval and second stage duration were significantly shorter in the high-dose group than in the control group. There were no measurable differences in the condition of the newborn infants between the three groups. To study the effects of early versus delayed oxytocin augmentation on the obstetrical and neonatal outcome in nulliparous women with spontaneous but prolonged labour.
                Randomised controlled study.
                Two delivery units in Sweden.
                Healthy nulliparous women with normal pregnancies, spontaneous onset of active labour, a cervical dilatation of 4-9 cm and no progress in cervical dilatation for 2 hours and for an additional hour if amniotomy was performed due to slow progress.
                Women (n = 630) were randomly allocated either to labour augmentation by oxytocin infusion (early oxytocin group) or to postponement of oxytocin augmentation for another 3 hours (expectant group).
                Mode of delivery (spontaneous vaginal or instrumental vaginal delivery or caesarean section) and time from randomisation to delivery.
                The caesarean section rate was 29 of 314 (9%) in the early oxytocin group and 34 of 316 (11%) in the expectant group (OR 0.8, 95% CI 0.5-1.4), and instrumental vaginal delivery 54 of 314 (17%) in the early oxytocin versus 38 of 316 (12%) in the expectant group (OR 1.5, 95% CI 0.97-2.4). Early initiation of oxytocin resulted in a mean decrease of 85 minutes in the randomisation to delivery interval.
                Early administration of oxytocin did not change the rate of caesarean section or instrumental vaginal delivery but shortened labour duration significantly in women with a 2-hour arrest in cervical dilatation. No other clear benefits or harms were seen between early and delayed administration of oxytocin.
Higher dose of oxytocin starting and increment dose (4 mU per minute or more) was associated with a reduction in the length of labour and in caesarean section, and an increase in spontaneous vaginal birth. However, there is insufficient evidence. The number of studies and the quality of the available evidence is of concern. Additionally, there is insufficient evidence for other maternal and neonatal outcomes, and how women feel about the higher doses of oxytocin. Therefore, no firm recommendation can be made. Further research should evaluate the effect of high dose oxytocin for women delayed in labour and should include these outcomes.