A randomized controlled trial to study the effect of IV hydration on the duration of labor in nulliparous women

Intravenous fluid rate of 250 mL/h versus 125 mL/h in nulliparous women: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Evidence regarding the type and rate of intravenous (IV) fluid administration during labor is still inconclusive and the studies assessing the impact of IV fluids had mixed results.

OBJECTIVES

To evaluate the effects of IV fluids at an infusion rate of 250 mL/h as compared with 125 mL/h on labor outcomes in nulliparous women.

SEARCH STRATEGY

We searched six databases for relevant studies through a search strategy containing the relevant keywords "IV hydration", "IV fluids", and "labor" from the inception of these databases to May 1, 2023, without any applied restrictions.

SELECTION CRITERIA

Search results were imported to Covidence for screening of eligible articles for this review. Randomized controlled trials (RCTs) assessing the impact of IV fluids at 250 mL/h on the outcomes of labor in nulliparous women at term (>37 weeks) as compared with 125 mL/h were included only.

DATA COLLECTION AND ANALYSIS

Data regarding the characteristics of included studies, participant's baseline characteristics, and concerned outcomes were collected in an Excel spreadsheet and all the concerned outcomes were pooled as risk ratios (RR) or mean difference (MD) with 95% confidence interval (CI) in the meta-analysis models using RevMan 5.4.

MAIN RESULTS

Pooled data from 11 RCTs with 1815 patients showed that 250 mL/h infusion rate had a significant reduction in cesarean section rate (RR 0.70, 95% CI 0.56-0.88, P = 0.002), the first stage of labor duration (MD -46.97, 95% CI -81.79 to -12.14, P = 0.008), the second stage of labor duration (MD -2.69, 95% CI -4.34 to -1.05, P = 0.001), prolonged labor incidence (RR 0.72, 95% CI 0.58-0.89, P = 0.003), as compared with 125 mL/h. Also, the vaginal delivery rate (RR 1.07, 95% CI 1.02-1.12, P = 0.009) was higher with a 250 mL/h infusion rate.

CONCLUSION

IV fluids at an infusion rate of 250 mL/h during labor in nulliparous women decreased the cesarean delivery rate, increased the vaginal delivery rate, shortened the first and second-stage labor duration, decreased the incidence of prolonged labor as compared with 125 mL/h. These findings suggest enhanced labor progression and a lower risk of labor complications with higher infusion rates. However, future research involving a more diverse population and exploring the potential benefits of combining IV infusion rates with other interventions, such as adding dextrose or less restrictive oral intake during labor, is needed.

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.

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.

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

BACKGROUND

Prolonged labor has been demonstrated to increase adverse maternal and neonatal outcome. A practice that may decrease the risk of prolonged labor is the modification of fluid intake during labor.

OBJECTIVE

Several studies demonstrated that increased hydration in labor as well as addition of dextrose-containing fluids may be associated with a decrease in length of labor. The purpose of our study was to characterize whether high-dose intravenous fluids, standard-dose fluids with dextrose, or high-dose fluids with dextrose show a difference in the duration of labor in nulliparas.

STUDY DESIGN

Nulliparous subjects with singletons who presented in active labor were randomized to 1 of 3 groups of intravenous fluids: 250 mL/h of normal saline, 125 mL/h of 5% dextrose in normal saline, or 250 mL/h of 2.5% dextrose in normal saline. The primary outcome was total length of labor from initiation of intravenous fluid in vaginally delivered subjects. Secondary outcomes included cesarean delivery rate and length of second stage of labor, among other maternal and neonatal outcomes.

RESULTS

In all, 274 subjects who met inclusion criteria were enrolled. There were no differences in baseline characteristics among the 3 groups. There was no difference in the primary outcome of total length of labor in vaginally delivered subjects among the 3 groups. First stage of labor duration, second stage of labor duration, and cesarean delivery rates were also equivalent. There were no differences identified in other secondary outcomes including clinical chorioamnionitis, postpartum hemorrhage, blood loss, Apgar scores, or neonatal intensive care admission.

CONCLUSION

There is no difference in length of labor or delivery outcomes when comparing high-dose intravenous fluids, addition of dextrose, or use of high-dose intravenous fluids with dextrose in nulliparous women who present in active labor.

Reduction of total labor length through the addition of parenteral dextrose solution in induction of labor in nulliparous: results of DEXTRONS prospective randomized controlled trial

BACKGROUND

Prolonged labor is a significant cause of maternal and fetal morbidity and very few interventions are known to shorten labor course. Skeletal muscle physiology suggests that glucose supplementation might improve muscle performance in case of prolonged exercise and this situation is analogous to the gravid uterus during delivery. Therefore, it seemed imperative to evaluate the impact of adding carbohydrate supplements on the course of labor.

OBJECTIVE

We sought to provide evidence as to whether intravenous glucose supplementation during labor induction in nulliparous women can reduce total duration of active labor.

STUDY DESIGN

We performed a single-center prospective double-blind randomized controlled trial comparing the use of parental intravenous dextrose 5% with normal saline to normal saline in induced nulliparous women. The study was conducted in a tertiary-level university hospital setting. Participants, caregivers, and those assessing the outcomes were blinded to group assignment. Inclusion criteria were singleton pregnancy at term with cephalic presentation and favorable cervix. Based on blocked randomization, patients were assigned to receive either 250 mL/h of intravenous dextrose 5% with normal saline or 250 mL/h of normal saline for the whole duration of induction, labor, and delivery. The primary outcome studied was the total length of active labor. Secondary outcomes included duration of the active phase of second stage of labor, the mode of delivery, Apgar scores, and arterial cord pH.

RESULTS

In all, 100 patients were randomized into each group. A total of 193 patients (96 in the dextrose with normal saline group and 97 in the normal saline group) were analyzed in the study. The median total duration of labor was significantly less in the dextrose with normal saline group (499 vs 423 minutes, P = .024) than in the normal saline group. The probabilities of a woman being delivered at 200 minutes and 450 minutes were 18.8% and 77.1% in the dextrose with normal saline group vs 8.2% and 59.8% in the normal saline group (Kolmogorov-Smirnov test P value = .027). There was no difference in the rate of cesarean delivery, instrumented delivery, Apgar score, or arterial cord pH.

CONCLUSION

Glucose supplementation significantly reduces the total length of labor without increasing the rate of complication in induced nulliparous women. Given the low cost and the safety of this intervention, glucose should be used as the default solute during labor.

Severe asymptomatic maternal antepartum hyponatremia leading to neonatal seizures: prevention is better than cure

Background

Pre-delivery maternal electrolyte derangements may reflect themselves in the newborn, since placental homeostasis determines electrolyte equilibrium between mother and fetus.

Case presentation

A term newborn, transferred to our Neonatal Intensive Care Unit 1 h after birth for an apnoea episode, presented with initially left-sided, and subsequently generalized tonic-clonic seizures due to severe hyponatremia (119 mmol/L). Seizures rapidly ceased after electrolyte correction plus a phenobarbital bolus. Deep hyponatremia was also detected in the mother (123 mmol/L).

Conclusions

As placental homeostasis determines electrolytes equilibrium between mother and fetus, obstetrics and neonatologists should be aware that any maternal dyselectrolytemia will reflect itself in the newborn; hence, it is fundamental to detect possible maternal electrolyte imbalances before delivery, in order to be prepared to timely correction of electrolyte derangements in the newborn.

A multi-center randomized trial of two different intravenous fluids during labor

OBJECTIVE

To determine if the intrapartum use of a 5% glucose-containing intravenous solution decreases the chance of a cesarean delivery for women presenting in active labor.

METHODS

This was a multi-center, prospective, single (patient) blind, randomized study design implemented at four obstetric residency programs in Pennsylvania. Singleton, term, consenting women presenting in active spontaneous labor with a cervical dilation of <6 cm were randomized to lactated Ringer's with or without 5% glucose (LR versus D5LR) as their maintenance intravenous fluid. The primary outcome was the cesarean birth rate. Secondary outcomes included labor characteristics, as well as maternal or neonatal complications.

RESULTS

There were 309 women analyzed. Demographic variables and admitting cervical dilation were similar among study groups. There was no significant difference in the cesarean delivery rate for the D5LR group (23/153 or 15.0%) versus the LR arm (18/156 or 11.5%), [RR (95% CI) of 1.32 (0.75, 2.35), p = 0.34]. There were no differences in augmentation rates or intrapartum complications.

CONCLUSIONS

The use of intravenous fluid containing 5% dextrose does not lower the chance of cesarean delivery for women admitted in active labor.

Intravenous fluids for reducing the duration of labour in low risk nulliparous women

BACKGROUND

Several factors may influence the progression of normal labour. It has been postulated that the routine administration of intravenous fluids to keep women adequately hydrated during labour may reduce the period of contraction and relaxation of the uterine muscle, and may ultimately reduce the duration of the labour. It has also been suggested that intravenous fluids may reduce caesarean sections (CS) for prolonged labour. However, the routine administration of intravenous fluids to labouring women has not been adequately elucidated although it is a widely-adopted policy, and there is no consensus on the type or volume of fluids that are required, or indeed, whether intravenous fluids are at all necessary. Women may be able to adequately hydrate themselves if they were allowed oral fluids during labour.Furthermore, excessive volumes of intravenous fluids may pose risks to both the mother and her newborn and different fluids are associated with different risks.

OBJECTIVES

To evaluate whether the routine administration of intravenous fluids to low-risk nulliparous labouring women reduces the duration of labour and to evaluate the safety of intravenous fluids on maternal and neonatal health.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (13 February 2013).

SELECTION CRITERIA

Randomised controlled trials of intravenous fluid administration to spontaneously labouring low-risk nulliparous women.

DATA COLLECTION AND ANALYSIS

The review authors independently assessed trials for inclusion, trial quality and extracted data.

MAIN RESULTS

We included nine randomised trials with 1781 women. Three trials had more than two treatment arms and were included in more than one comparison.Two trials compared women randomised to receive up to 250 mL/hour of Ringer's lactate solution as well as oral intake versus oral intake only. For women delivering vaginally, there was a reduction in the duration of labour in the Ringer's lactate group (mean difference (MD) -28.86 minutes, 95% confidence interval (CI) -47.41 to -10.30). There was no statistical reduction in the number of CS in the Ringer's lactate group (risk ratio (RR), 0.73 95% CI 0.49 to 1.08).Three trials compared women who received 125 mL/hour versus 250 mL/hour of intravenous fluids with free oral fluids in both groups. Women receiving a greater hourly volume of intravenous fluids (250 mL) had shorter labours than those receiving 125 mL (MD 23.87 minutes, 95% CI 3.72 to 44.02, 256 women). There was no statistically significant reduction in the number of CS in the 250 mL intravenous fluid group (average RR 1.00, 95% CI 0.54 to1.87, three studies, 334 women). In one study the number of assisted vaginal deliveries was lower in the group receiving 125 mL/hour (RR 0.47, 95% CI 0.27 to 0.81).Four trials compared rates of intravenous fluids in women where oral intake was restricted (125 mL/hour versus 250 mL/hour). There was a reduction in the duration of labour in women who received the higher infusion rate (MD 105.61 minutes, 95% CI 53.19 to 158.02); P < 0.0001, however, findings must be interpreted with caution as there was high heterogeneity amongst trials (I(2) = 53%). There was a significant reduction in CS in women receiving the higher rate of intravenous fluid infusion (RR 1.56, 95% CI 1.10 to 2.21; P = 0.01). There was no difference identified in the assisted delivery rate (RR 0.78, 95% CI 0.44 to 1.40). There was no clear difference between groups in the number of babies admitted to the NICU (RR 0.48, 95% CI 0.07 to 3.17).Two trials compared normal saline versus 5% dextrose. Only one reported the mean duration of labour, and there was no strong evidence of a difference between groups (MD -12.00, 95% CI -30.09 to 6.09). A trial reporting the median suggested that the duration was reduced in the dextrose group. There was no significant difference in CS or assisted deliveries (RR 0.77, 95% CI 0.41 to 1.43, two studies, 284 women) and (RR 0.59, 95% CI 0.21 to 1.63, one study, 93 women) respectively. Only one trial reported on maternal hyponatraemia (serum sodium levels < 135 mmol/L ). For neonatal complications, there was no difference in the admission to NICU) or in low Apgar scores, however 33.3% of babies developed hyponatraemia in the dextrose group compared to 13.3 % in the normal saline group (RR 0.40, 95% CI 0.17 to 0.93) (P = 0.03). One trial reported a higher incidence of neonatal hyperbilirubinaemia in the dextrose group of babies. There was no difference in neonatal hypoglycaemic episodes between groups.

AUTHORS' CONCLUSIONS

Although the administration of intravenous fluids compared with oral intake alone demonstrated a reduction in the duration of labour, this finding emerged from only two trials. The findings of other trials suggest that if a policy of no oral intake is applied, then the duration of labour in nulliparous women may be shortened by the administration of intravenous fluids at a rate of 250 mL/hour rather than 125 mL/hour. However, it may be possible for women to simply increase their oral intake rather than being attached to a drip and we have to consider whether it is justifiable to persist with a policy of 'nil by mouth'. One trial raised concerns about the safety of dextrose and this needs further exploration.None of the trials reported on the evaluation of maternal views of being attached to a drip during their entire labour. Furthermore, there was no objective assessment of dehydration. The evidence from this review does not provide robust evidence to recommend routine administration of intravenous fluids. Interpreting the results from trials was hampered by the low number of trials contributing data and by variation between trials. In trials where oral fluids were not restricted there was considerable variation in the amount of oral fluid consumed by women in different arms of the same trial, and between different trials. In addition, results from trials were not consistent and risk of bias varied. Some important research questions were addressed by single trials only, and important outcomes relating to maternal and infant morbidity were frequently not reported.

Increased intravenous hydration of nulliparas in labor

OBJECTIVE

To assess the effects of intravenous hydration on the duration of active labor in nulliparous women also allowed unrestricted oral consumption of fluids.

METHODS

In a randomized clinical trial 120 nulliparous women with uncomplicated singleton pregnancies at term were randomly assigned to drink fluids at will and receive either no intravenous hydration (group 1) or a Ringer lactate solution at rates of 60 mL, 120 mL, or 240 mL per hour (groups 2-4) throughout active labor.

RESULTS

There were differences in duration for the active phase of the first stage of labor (252.3 ± 40.9 min in group 1 vs 206.7±38.3 min in group 4; P<0.001) and for the second stage (64.3 ± 13.9 in group 1 vs 49.8 ± 11.4 min in group 4; P=0.01), but not for the third stage. The percentage of participants who needed labor augmentation with oxytocin was less when intravenous hydration was provided (53.3% in group 1 vs 20.0% in group 4; P=0.02).

CONCLUSION

Intravenous hydration significantly decreased the duration of active labor and reduced the frequency of both prolonged labor and oxytocin administration in nulliparous women. htpp://www.irct.ir registration number: IRCT201105256575N2.