Intravenous Ringer's lactate versus usual care during labor in nulliparous women: a systematic review and meta-analysis of randomized controlled trials

Background: Due to limited research on the effectiveness and safety of intravenous (IV) fluids administered during labor, there are no guidelines available. Thus, this meta-analysis aims to evaluate efficacy of IV Ringer's lactate during labor as compared to usual care.Methods: Six databases were searched for the randomized controlled trials (RCTs) comparing the effects of IV Ringer's lactate at 125 mL/h or 250 mL/hr during labor in nulliparous women at term as compared to usual care, and the search results were imported to Covidence for screening of the articles. All the concerned outcomes were pooled as risk ratios (RR) or mean difference (MD) with 95% CI in the meta-analysis models using RevMan 5.4.Results: Pooled data from 7 RCTs with 967 nulliparous women showed that the active stage of labor duration (MD -32.16 with 95% CI [40.43 to -23.90], p < 0.00001), need of oxytocin augmentation (RR 0.72 with 95% CI [0.54 to 0.96], p = 0.03) and incidence of prolonged labor (RR 0.57 with 95% CI [0.34 to 0.95], p = 0.03) was significantly lower with IV Ringer's lactate. However, the total duration of labor (p = 0.23), duration of second stage of labor (p = 0.31) and cesarean section rate (p = 0.070) did not differ between the two groups. The test for subgroup analysis based on infusion rate was significant (p = 0.01) for the active stage of labor.Conclusion: IV Ringer's lactate reduced the duration of active labor, the need for oxytocin augmentation and the prolonged labor incidence. However, it did not differ in effect on immediate neonatal health but was found to have more potential for reducing maternal vomiting as compared to usual care with unrestricted oral intake. Further research is needed to explore its effects in the larger and more diverse populations and with different IV fluids for evidence-based guidelines.