[Effects of a policy for reasonable use of oxytocin during spontaneous labor at term]

To assess the effect of a modified definition of dystocia and of a different timing of interventions during spontaneous labor on the rate of oxytocin use and on its consequences on labor outcome.

We compared oxytocin use and labor outcome before and after the introduction of a new protocol for the management of spontaneous labor. By protocol, oxytocin use and/or artificial rupture of the membranes was restricted to cases without progress in cervical dilatation for≥1h and/or no progress of fetal descent for≥1h at full dilatation. The main outcome measure was the rate of oxytocin use. Secondary outcome criteria were the consequences on labor (duration of labor, tachysystole and uterine hyperstimulation, abnormal fetal heart rate, cesarean delivery rate) and neonatal outcome.

Oxytocin use was strongly reduced from 2015 (69.2%) to 2016 (39.8%; P<0.01) and 2017 (31.9%; P<0.01). Abnormal FHR rates decreased simultaneously (respectively 52%, 37% et 29%, P<0.05), as well as uterine hyperstimulation (respectively 33.6%, 21.3% et 23.0%; P<0.05). The cesarean delivery rate did not vary significantly from 2015 (11.5%) to 2016 (8.4%; NS) but it decreased from 2015 to 2017 (11.5% to 2.6%, respectively; P<0.05). No difference was found in postpartum hemorrhage rates or in neonatal outcome. The duration of labor was significantly longer for women who delivered in 2017, compared with 2015 (372 minutes versus 306 minutes, respectively; P<0.05). After multivariate analysis, FHR abnormalities were reduced (aOR 0.65 IC 95% [0.49-0.86]) as well as cesarean deliveries during labor (aOR 0.5 IC 95% [0.26-0.97]) in 2017 only, compared with the reference year 2015.

A simple and easy-to-use definition of dystocia and of interventions required during labor allowed a strong reduction of oxytocin use during labor with subsequent benefits such as reduced rates of FHR abnormalities, uterine hyperstimulations and cesarean deliveries, at the cost of a limited prolongation of labor, mainly in nulliparous women.