Continued versus discontinued oxytocin stimulation in the active phase of labour (CONDISOX): double blind randomised controlled trial

Abstract

Abstract Objective To determine whether discontinuing oxytocin stimulation in the active phase of induced labour is associated with lower caesarean section rates. Design International multicentre, double blind, randomised controlled trial. Setting Nine hospitals in Denmark and one in the Netherlands between 8 April 2016 and 30 June 2020. Participants 1200 women stimulated with intravenous oxytocin infusion during the latent phase of induced labour. Intervention Women were randomly assigned to have their oxytocin stimulation discontinued or continued in the active phase of labour. Main outcome measure Delivery by caesarean section. Results A total of 607 women were assigned to discontinuation and 593 to continuation of the oxytocin infusion. The rates of caesarean section were 16.6% (n=101) in the discontinued group and 14.2% (n=84) in the continued group (relative risk 1.17, 95% confidence interval 0.90 to 1.53). In 94 parous women with no previous caesarean section, the caesarean section rate was 7.5% (11/147) in the discontinued group and 0.6% (1/155) in the continued group (relative risk 11.6, 1.15 to 88.7). Discontinuation was associated with longer duration of labour (median from randomisation to delivery 282 v 201 min; P<0.001), a reduced risk of hyperstimulation (20/546 (3.7%) v 70/541 (12.9%); P<0.001), and a reduced risk of fetal heart rate abnormalities (153/548 (27.9%) v 219/537 (40.8%); P<0.001) but rates of other adverse maternal and neonatal outcomes were similar between groups. Conclusions In a setting where monitoring of the fetal condition and the uterine contractions can be guaranteed, routine discontinuation of oxytocin stimulation may lead to a small increase in caesarean section rate but a significantly reduced risk of uterine hyperstimulation and abnormal fetal heart rate patterns. Trial registration ClinicalTrials.gov NCT02553226 .