A Comparative Study of Low and High Dose Oxytocin Augmentation on Labor and Perinatal Outcome

Kwak, J H; Kang, J Y; Hwang, S Y; Cha, M S; Hwang, T Y; Kim, H H; Je, K W

Abstract

Oxytocin is frequently used in obstetrics for induction and augmentation of labor. Injudicious use of oxytocin can cause hyperstimulation and subsequent fetal hypoxia. In this study, low and high dose protocols of oxytocin were used to augment nonprogressive labor in normal nulliparous women. In the low dose oxytocin group, the rate of oxytocin infusion was maintained at the physiologic dose (2.75 mU/min) and in the high dose oxytocin group, was started at 4 mU/min and was increased by 4 mU/min to a maximum 40 mU/min. The aim of this study was to assess the effects of the low physiologic dose and high dose oxytocin augmentation on labor and perinatal outcomes in nulliparous women. The results were as follows: 1. The mean maternal age and birth weight were comparable. 2. No statistical difference was detected in the mode of delivery. 3. No statistical difference was detected in the duration of the active phase of the first stage of labor and of the second stage of labor but marked reduction in the total amount of oxytocin in the low dose oxytocin group (p< 0.05). 4. No statistical difference was detected in the incidence of adequate labor, hyperstimulation, and fetal heart rate deceleration. 5. No statistical difference was detected in the occurrence of fetal asphyxia as measured by the incidence of meconium staining, umbilical arterial pH, umbilical arterial base excess, and Apgar score below 7 at 5 minutes. But the uric acid concentration in umbilical blood was higher in the high dose oxytocin group (p<0.05). The results suggested that the use of the low physiologic dose oxytocin was able to augment nonprogressive labor effectively, reduce the total amount of oxytocin and possibility of acute hypoxemia that was not documented by standard markers of perinatal hypoxia at delivery.