In 2017, the French national authority for health issued national guidelines to support physiologic labor and reduce medical interventions. This study's primary aim was to evaluate the association between the publication of these guidelines and the vaginal delivery rate in a type IIb perinatal center. The secondary objectives were to evaluate the implementation of these guidelines, their association with the duration of labor, and the rates of postpartum hemorrhage and adverse neonatal outcomes.

A before-and-after, retrospective, single-center study comparing a "before" group (2016) and an "after" group (2018), one year after the recommendations were published. Women were eligible if they had no prior cesarean delivery and gave birth after 37 weeks of gestation to a singleton fetus in cephalic presentation after spontaneous labor. The analysis was stratified by parity.

Oxytocin administration decreased between the two periods (48% vs 35 %, P < 0.0001), as did the frequency of amniotomies (artificial rupture of membranes) (39.5 % vs 27.7 %, P < 0.0001). The duration of labor was significantly prolonged (360 vs 390 min, P < 0.0001), especially in nulliparous women (465 min vs 562 min, P<0.0001). The frequency of vaginal delivery rose between the two periods (94.6 % vs 96 %, P = 0.05), and the postpartum hemorrhage rate fell (6 % vs 4.5 %, P = 0.04). The numbers of neonates with an umbilical artery pH< 7.10 and of neonatal transfers also decreased.

The reduction of active interventions during labor is associated with a longer duration of labor and a decrease in the rates of cesarean births, postpartum hemorrhages, and neonatal transfers.