Randomized control trial investigation of the effect of high-dose versus low-dose oxytocin regimens in induction of labour

ABSTRACT

Induction of labour means stimulation of uterus to increase the frequency, duration and strength of contractions. There are numerous methods for induction of labour, but use of synthetic oxytocin is the most common method. In the academic hospitals, approximately 20-30 percent of labours are induced by use of oxytocin. There are two regimens for oxytocin administration i.e. low-dose and high-dose oxytocin. This study was performed to determine the effect of high-dose versus low-dose oxytocin regimens to induce labour in post-term pregnancies in primigravid women. sixty pregnant women were entered into this prospective, randomized, double blind clinical trial. The patients were assigned into two groups by randomized block sampling. Our study included primigravid pregnant women for whom the only indication for induction of labour was post-term pregnancy. Patients were randomly assigned into two groups [n=30] and received oxytocin according to either a low-dose or high-dose protocol. The required Data were extracted by observation, patient interview and also patients records. Statistical analysis was performed by means of X[2] and Mann-Whitney U tests. P value of <0.05 was considered statistically significant. There was no significant difference in the mean cervical dilatation, gestational age and maternal age before induction of labour in the 2 groups. Mean durations of active phase were 249.29 minutes and 191.91 minutes in the low-dose and high-dose groups respectively [p>0.05]. The mean values for hospitalization time from admission to complete dilatation of cervix were 512.47 and 449.95 minutes in the low-dose and high-dose groups correspondingly. The mean time from admission to delivery was 552.9 minutes in the low-dose group versus 512.16 minutes in the high-dose group. Lack of response to induction encountered in 20% and 33.3% of the cases of high-dose and low-dose groups accordingly [p>0.05]. The most common cause of cesarean section in the two groups was unresponsiveness to induction [46.1% in low-dose and 42.7% in high dose groups]. We faced 2 cases of neonatal death [6.7%] in the low-dose group. We conclude that high-dose oxytocin regimen shortens labour time. Therefore fewer cesarean sections are required and neonatal outcome will be better. Nonetheless the rate of hyperstimulation is more when high-dose oxytocin regimen is used