Oxytocin Titration for Induction of Labour: A Prospective Randomized Study of 15 Versus 30 Minute Dose Increment Schedules
Authors: Chua S. , Arulkumaran S. , Kurup A. , Tay D. , Ratnam S. S. 
Published: February 2008

EDITORIAL COMMENT: : The onset of labour is induced in approximately 1 in 5 women, and spontaneous labours are augmented with oxytocin infusions in 1 in 6A. At the Mercy Maternity Hospital, and presumably in many other midwifery hospitals, the incidence of surgical induction of labour is 23% and 85 % of women having surgical induction receive an oxytocin infusionB. These statistics bear witness to the enormous workload imposed upon labour ward nursing staff whose duty it is to supervise the administration of oxytocin infusions.

This paper confirms other reports that oxytocin titration for induction of labour is just as effective with 30‐minute dose increments as with the more time consuming 15‐minute increments. Since the risks of fetal distress and hyperstimulation are similar with both regimens, it is surely sensible to favour the 30‐minute method.

Although it is usual to distinguish between augmentation and induction of labour with an oxytocin infusion, it should be obvious that a labour induced by oxytocin becomes a labour augmented by oxytocin, unless, which is uncommon, the infusion is discontinued when labour becomes established. This point is made to stress the fact that the risk of uterine rupture to the multipara labouring against unrecognized obstruction, can occur in induced labours in addition to those where spontaneous labour is augmented.

In this study the oxytocin infusions were apparently started at the time of amniotomy. This has become an accepted regimen presumably to minimize the induction‐delivery interval and hence lessen the risks to mother and fetus of intrauterine infection, albeit at the risks of receiving an oxytocin infusion. A re all these oxytocin infusions necessary? They are expensive in nurses' time and cost of infusion equipment. They are the blight on the lives of medical students during their rostered time in delivery suites, since they are often asked to ‘sit with the drip’ rather than observe more generally the progress of labour and deliveries of all the women in labour. Thirty years ago the accepted regimen was for an oxytocin infusion to begin 24 hours after surgical induction when labour had not occurred. Have we gone from one extreme to the other? Why do we not allow 4, 8 or 12 hours to elapse after amniotomy before the oxytocin infusion is commenced? From the point of view of patients, many of whom wish to avoid an oxytocin infusion when induction of labour is indicated, we should assess whether there is a better method than ‘double induction therapy’. We would like to publish data on such trials in this journal.

Summary: : Two hundred and twenty four patients admitted for induction of labour were randomized into 2 groups. The oxytocin dose was escalated every 15 minutes in the first group whilst for the second group the dose was increased every 30 minutes till optimal uterine activity was achieved. There was no significant difference in the mean maximum dose of oxytocin and length of labour in the 2 groups studied. Transient reduction of the dose of oxytocin was needed in 20.5% of patients in the ‘15 minute’ group and 17.0% of cases in the ‘30 minute’ group because of uterine hyperstimulation or fetal heart rate (FHR) changes; this difference was not statistically significant. The incidence of operative deliveries were similar in the 2 groups. The neonatal 1 and 5 minute Apgar scores, cord arterial blood pH, incidence of assisted ventilation and admission to the neonatal intensive care unit were similar in the 2 groups. The 15 minute schedule does not offer any advantage over the 30 minute escalation schedule for induction of labour. Hyperstimulation and FHR changes are a possibility with any regimen and close monitoring of FHR and uterine activity is advisable with the use of oxytocin.