Changes in labor outcomes after implementing structured use of oxytocin augmentation with a 4-hour action line

Oxytocin augmentation is essential in labor management, but how to optimize its use is still debated. Joint international guidelines regarding prolonged labor and the use of oxytocin augmentation are still not available. Due to its potential harmful side effects, a decreased use of oxytocin is encouraged. We aimed to implement a structured protocol on the use of oxytocin augmentation and to observe changes in labor outcomes.

The protocol was implemented at the Obstetric Department of Sørlandet Hospital, Kristiansand, Norway on 1 January 2012; therefore, data from the hospital were collected prospectively and compared for two time-period cohorts: the historic control cohort (2009-2010) and the study period cohort (2012-2013). The structured protocol instructs, and restricts, the birth attendants to diagnose prolonged labor, by protocol definition only, before commencing oxytocin infusion for augmentation. Nulliparous women with singleton, term deliveries (≥37 weeks), cephalic presentation, and spontaneous onset of labor (Ten-Group Classification System (TGCS) group 1) were included in the analysis. The main outcome was use of oxytocin augmentation.

The study cohort and control cohort comprised 1103 (26.2%) and 1399 (33.1%) of all laboring women, respectively (p < .01). The protocol was followed satisfactorily in 78% of the study cohort. The use of oxytocin augmentation was reduced in the study cohort versus the control cohort; 41.3 versus 48.9% (p < .01); mean oxytocin infusion duration was shorter (100 versus 123 min; p < .01); and mean total oxytocin dose decreased (1009 versus 1293 mU; p < .01). The cesarean section rate was 5.9% in the study cohort versus 8.0% in the control cohort (p = .04). The estimated mean duration of the active phase of labor increased by 47 min (p < .01) after the implementation. The frequency of estimated postpartum hemorrhage >1000 ml was higher, 4.9 versus 2.0% (p < .01), but the use of blood transfusions remained stable, 2.5 versus 2.7% (p = .78), the study cohort versus control cohort, respectively.

Implementation of a protocol of structured use of oxytocin augmentation reduced the frequency, dosage, and duration of oxytocin without increasing the cesarean section rate in TGCS group 1.