Efficacy of "optimal hydration" during labor: HYDRATA study protocol for a randomized clinical trial

The effects of intravenous hydration regimens in nulliparous women undergoing induction of labor: A systematic review and meta-analysis

INTRODUCTION

Labor is both a physiological and physical activity that requires energy expenditure by the woman. Despite this, women are often fasted in labor, with hydration requirements addressed predominantly by intravenous therapy. Little is known about how best to manage this in nulliparous women undergoing induction of labor, who can be prone to lengthy labors. Therefore, we undertook a systematic review and meta-analysis to determine the effects of intravenous hydration regimens on nulliparous women undergoing induction of labor.

MATERIAL AND METHODS

A systematic review and meta-analysis were conducted. Databases searched were PubMed, CINAHL, Embase, Cochrane, Scopus, and Web of Science using the search strategy combination of associated key concepts for intravenous therapy and nulliparous laboring women. The primary outcome was excessive neonatal weight loss. Meta-analyses for categorical outcomes included estimates of odds ratio (OR) and their 95% confidence intervals (CI) calculated; and for continuous outcomes the standardized mean difference, each with its 95% CI. Heterogeneity was assessed visually and by using the χ2 statistic and I2 with significance being set at p < 0.10.

RESULTS

A total of 1512 studies were located and following screening, three studies met the eligibility criteria. No studies reported excessive neonatal weight loss. Increased rates of intravenous therapy (250 mL/h vs. 125 mL/h) during labor were not found to reduce the overall length of labor (mean difference -0.07 h, 95% CI -0.27 to 0.13 h) or reduce cesarean sections (OR 0.74, 95% CI 0.45-1.23), when women were not routinely fasted.

CONCLUSIONS

Our review found no significant improvements for nulliparous women who received higher intravenous fluid volumes when undergoing induction of labor and were not routinely fasted. However, data are limited, and further research is needed.

Comparative evaluation of normal saline, 1/3-2/3, and ringer's lactate infusion on labour outcome, PH, bilirubin, and glucose level of the umbilical cord blood in nulliparous women with labour induction: a randomised clinical trial

This study aimed to compare the effects of infusion of normal saline, 1/3-2/3, and Ringer's lactate fluids on labour outcome, pH, bilirubin, and glucose level of umbilical cord blood. In this randomised clinical trial, 450 nulliparous women with Bishop score ˂5 and indication of pregnancy termination were randomly divided into three groups to receive normal saline, 1/3-2/3, or Ringer's lactate infusion at a rate of 125 mL/h for hydration, upon starting induction of labour. Results of this study indicated that the incidence of hypoglycaemia (p = .19), hyper bilirubinemia (p = .87) and acidosis (p = .10) was similar in neonates of the three groups. Also, there were no statistically significant differences between the three groups with regard to the duration of labour; glucose, bilirubin and pH level of cord blood; and mode of delivery. It can be concluded that infusion of Ringer's lactate, normal saline or 1/3-2/3 fluid during labour is not associated with different maternal or foetal/neonatal outcomes, and none of the fluids has superiority to the others.Impact statementWhat is already known on this subject? Several studies have been conducted on the association between type and volume of infused fluid on labour duration and neonatal outcomes. However, there has been some controversy.What do the results of this study add? This is the first study that has investigated the association between infusion of Ringer's lactate, normal saline or 1/3-2/3 fluid during labour with labour outcome and pH, bilirubin, and glucose level of the umbilical cord blood and results showed that these fluids have no effect on maternal or foetal/neonatal outcomes and also none of these fluids has superiority to the others.What are the implications of these findings for clinical practice and/or further research? Due to contradictory results of previous studies, further research with greater sample sizes and different fluids type and volumes may be needed to examine the association between infusion of fluids and neonatal and labour outcomes more precisely.