Despite its widespread use throughout the labor process, no advantage exists to continuing oxytocin infusion after the onset of active labor, according to a small trial of 104 women in Israel. Researchers found that stopping oxytocin at 5 cm dilation, instead of continuing it until delivery, shortened labor, though not significantly so, and halved the number of cesarean sections required.
The researchers admit that the study was underpowered and that the findings could be the result of chance, but their results also support the hypothesis that continuing oxytocin once the active phase of labor has begun actually complicates labor by desensitizing uterine receptors to exogenous and endogenous oxytocin.
Daniel-Spiegel E, Weiner Z, Ben-Shlomo I, et al. For how long should oxytocin be continued during induction of labour? BJOG. 2004;111:331-334.