A randomized, double-blinded, controlled trial of the effects of fluid rate and/or presence of dextrose in intravenous fluids on the labor course of nulliparas

The association of intrapartum IV fluid rates during labor with birth weight

PURPOSE

Since discovering that intravenous (IV) fluid infusion rate of 250 mL/hr during labor decreases incidence of cesarean delivery and decreases time in labor when compared to infusion rate of 125 mL/hr, patients and midwives have expressed concern that increased fluid rates may lead to increased birth weights. Thus, our objectives were to determine the impact, if any, of increased IV fluid infusion rates on birth weight.

METHODS

This was a meta-analysis of all randomized controlled trials (RCTs) of low-risk, nulliparous women with gestations ≥ 36 weeks comparing IV fluid rates of 125 vs. 250 mL/hr. We conducted a comprehensive literature search to identify studies published since the meta-analysis by Ehsanipoor et al. (2017) that assessed the impact of IV fluid rate on birth weight. For our analysis, we included the articles published since 2017 as well as articles from the original meta-analysis that included birth weight (6/7 studies).

RESULTS

Eight trials, with an overall low risk of bias, including 1727 women were analyzed. 913 were in the 125 ml/hr group and 876 were in the 250 ml/hr group. The vast majority of the included trials used Ringer's solution or normal saline. Overall, there was no significant difference in birth weights between the two treatment groups (mean difference -22.69 g; 95 % CI -75.52 to + 27.14).

CONCLUSIONS

We conclude that in addition to the previously demonstrated decreased incidence of cesarean delivery and length of labor demonstrated in Ehsanipoor et al. afforded by increased rate of IV fluid intake, there is no significant impact on birth weight.

A double-blinded randomised controlled study of fluid restriction versus liberal fluid during induction of labour: A pilot study

BACKGROUND

Excess intravenous fluid for women requiring an induction of labour may adversely affect the duration of labour and maternal/neonatal outcomes.

AIMS

This study aimed to determine the difference in duration of labour and outcomes with a low background infusion rate, compared to liberal background intravenous fluid management.

MATERIALS AND METHODS

A double blind randomised controlled pilot study was performed on 200 women who underwent induction of labour at a single institution. Women were randomised to an intravenous rate of 40 mL/h versus 250 mL/h of Hartmann's solution. Fluid boluses were strictly controlled to limit bias. This trial was registered with the Australian clinical trial registry: ACTRN12621001298808.

RESULTS

Analysis of the total amount of fluid received showed good separation with Group 1 (40 mL/h) receiving 1,736 mL less than Group 2 (250 mL/h), median (interquartile range) 841 mL (458, 1691) versus 2,577 mL (1620, 4326) (P < 0.001). Median duration of labour was shorter in Group 1 by 24 min (P = ns). Subset analysis of nulliparous women showed that duration of labour was shorter in Group 1 by 83.5 min (P = ns).

CONCLUSION

As this was a pilot study, a significant difference in duration of labour or secondary outcomes was not seen. Given the increasing numbers of nulliparous women having an induction of labour, potential for adverse maternal and neonatal outcomes and the associated higher rate of operative birth, this study guides power calculations and supports proof of concept for future research into optimum fluid management during induction of labour for these women.

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.

A double-blinded randomized controlled trial on the effects of increased intravenous hydration in nulliparas undergoing induction of labor

BACKGROUND

Rates of labor induction are increasing, raising concerns related to increased healthcare utilization costs. High-dose intravenous fluid (250 cc/h) has been previously demonstrated to shorten the time to delivery in nulliparous individuals in spontaneous labor. Whether or not this relationship exists among individuals undergoing induction of labor is unknown.

OBJECTIVE

Our study aimed to evaluate the effect of high-dose intravenous hydration on time to delivery among nulliparous individuals undergoing induction of labor.

STUDY DESIGN

Nulliparous individuals presenting for induction of labor with a Bishop score of ≤6 (with and without rupture of membranes) were randomized to receive either 125 cc/h or 250 cc/h of normal saline. The primary outcome was length of labor (defined as time from initiation of study fluids to delivery). Both time to overall delivery and vaginal delivery were evaluated. Secondary outcomes included the lengths of each stage of labor, the percentage of individuals delivering within 24 hours, and maternal and neonatal outcomes, including cesarean delivery rate.

RESULTS

A total of 180 individuals meeting inclusion criteria were enrolled and randomized. Baseline demographic characteristics were similar between groups; however, there was a higher incidence of diabetes mellitus in the group receiving 125 cc/h. Average length of labor was similar between groups (27.6 hours in 250 cc/h and 27.8 hours in 125 cc/h), as was the length of each stage of labor. Cox regression analysis did not demonstrate an effect of fluid rate on time to delivery. Neither the admission Bishop score, body mass index, nor other demographic characteristics affected time to delivery or vaginal delivery. There were no differences in maternal or neonatal outcomes, including overall cesarean delivery rate, clinically apparent iatrogenic intraamniotic infection, Apgar scores, need for neonatal phototherapy, or neonatal intensive care unit stay.

CONCLUSION

There were no observed differences in the length of labor or maternal or neonatal outcomes with the administration of an increased rate of intravenous fluids among nulliparous individuals undergoing induction of labor.

Dextrose intravenous fluid therapy in labor reduces the length of the first stage of labor

The aim of this systematic review with meta-analysis was to evaluate the effect on length of labor when patients receive IVF with or without dextrose. Searches were performed in electronic databases from inception of each database to May 2018. Trials comparing intrapartum IVF containing dextrose (i.e. intervention group) with no dextrose or placebo (i.e. control group) were included. Only trials examining low-risk pregnancies in labor at ≥36 weeks were included. Studies were included regardless of oral intake restriction. The primary outcome was the length of total labor from randomization to delivery. The meta-analysis was performed using the random effects model. Sixteen trials (n = 2503 participants) were included in the meta-analysis. Women randomized in the IVF dextrose group did not have a statistically significant different length of total labor from randomization to delivery compared to IVF without dextrose (MD -38.33 min, 95% CI -88.23 to 11.57). IVF with dextrose decreased the length of the first stage (MD -75.81 min, 95% CI -120.67 to -30.95), but there was no change in the second stage. In summary, use of IVF with dextrose during labor in low-risk women at term does not affect total length of labor, but it does shorten the first stage of labor.