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Standard- or high-dose oxytocin for nulliparous women with confirmed delay in labour: quantitative and qualitative
S Kenyon1, N Armstrong, T Johnston
1School of Health and Population Sciences, University of Birmingham, Birmingham, UK.
Objective:
Evidence suggests that a high dose of oxytocin for nulliparous women at 37-42 weeks of gestation with confirmed delay in labour increases spontaneous vaginal birth. We undertook a pilot study to test the feasibility of this treatment.
Design:
Pilot double-blind randomised controlled trial.
Setting:
Three teaching hospitals in the UK.
Population:
A total of 94 consenting nulliparous women at term with confirmed delay in labour were recruited, and 18 were interviewed.
Methods:
Women were assigned to either a standard (2 mU/min, increasing every 30 minutes to 32 mU/minute) or a high-dose regimen (4 mU/minute, increasing every 30 minutes to 64 mU/minutes) oxytocin by computer-generated randomisation. Simple descriptive statistics were used, as the sample size was insufficient to evaluate clinical outcomes. The constant comparative method was used to analyse the interviews.
Main Outcomes Measures:
The main outcome measures: number of women eligible; maternal and neonatal birth; safety; maternal psychological outcomes and experiences; health-related quality of life outcomes using validated tools and data on health service resource use; incidence of suspected delay of labour (cervical dilatation of <2 cm after 4 hours, once labour is established); and incidence of confirmed delay of labour (progress of <1 cm on repeat vaginal examination after a period of 2 hours).
Results:
We successfully developed systems to recruit eligible women in labour and to collect data. Rates of spontaneous vaginal birth (10/47 versus 12/47, RR 1.2, 95% CI 0.6-2.5) and caesarean section (15/47 versus 17/47, RR 1.1, 95% CI 0.6-2.0) were increased, and rates of instrumental birth were reduced (21/47 versus 17/47, RR 0.8, 95% CI 0.5-1.3). No evidence of increased harm for either mother or baby was found. The incidences of suspected delay (14%) and confirmed delay (11%) in labour were less than anticipated. Of those who did not go on to have delayed labour confirmed, all except one woman gave birth vaginally.
Conclusions:
A pilot trial assessing the efficacy of high-dose oxytocin was feasible, but uncertainty remains, highlighting the need for a large definitive trial. The implementation of national guidance of suspected and confirmed delay in labour is likely to reduce intervention.
