Increased intravenous fluid intake and the course of labor in nulliparous women

Intrapartum hydration assessment and management: A cross-sectional survey of Australian and New Zealand maternity units

BACKGROUND

Hydration assessment and management during labour play an important role in maternal and newborn outcomes. Studies indicate that clinical practice is inconsistent, with limited consensus evident in clinical guidelines. Current practices in fluid management across public and private maternity units within Australia and New Zealand remain unknown. Respondents highlighted the importance of maternal hydration assessment and management to well-being. However, inconsistencies were noted in the documentation, medication use and adherence to clinical protocols.

AIM

Our study aimed to investigate unit-level clinical practice regarding intrapartum hydration assessment and management across Australian and New Zealand private and public hospitals. The scope of this study focuses on fluid management during both spontaneous and induced labour.

METHOD

We conducted a cross-sectional, descriptive survey to assess the fluid management practices of Australian and New Zealand maternity services.

RESULTS

Of the 307 eligible maternity units, 89 participated (responding key informants included midwives, obstetricians, managers, and educators). All acknowledged the importance of maternal intrapartum hydration assessment and management. However, variations existed in assessment methods, with urine colour (87.6 %, n = 78) and frequency (84.3 %, n = 75), as well as maternal and fetal vital sign assessments (83.1 %, n = 74) being most prevalent. Documentation format and tools varied, and midwives identified this as their role. Despite the significance attributed to hydration by clinicians, not all felt confident in their capabilities to assess or manage intrapartum hydration. Free-text responses emphasised the significance of this topic from an educational perspective.

CONCLUSION

Respondents highlighted the significance of maternal intrapartum hydration assessment and maternal and newborn well-being management. However, inconsistent documentation, medication usage, including intravenous fluids, and clinical protocols were evident.

Evidence-based guidelines for intrapartum maternal hydration assessment and management: A scoping review

PROBLEM

Inconsistent practice relating to intrapartum hydration assessment and management is reported, and potential harm exists for laboring women and birthing persons.

BACKGROUND

Labor and birth are physically demanding, and adequate nutrition and hydration are essential for labor progress. A lack of clear consensus on intrapartum hydration assessment and management during labor and birth currently exists. In addition, there is an inconsistent approach to managing hydration, often including a mixture of intravenous and oral fluids that are poorly monitored.

AIM

The aim of this scoping review was to identify and collate evidence-based guidelines for intrapartum hydration assessment and management of maternal hydration during labor and birth.

METHODS

PubMed, Embase, and CINAHL databases were searched, in addition to professional college association websites. Inclusion criteria were intrapartum clinical guidelines in English, published in the last 10 years.

FINDINGS

Despite searching all appropriate databases in maternity care, we were unable to identify evidence-based guidelines specific to hydration assessment and management, therefore resulting in an "empty review." A subsequent review of general intrapartum care guidelines was undertaken. Our adapted review identified 12 guidelines, seven of which referenced the assessment and management of maternal hydration during labor and birth. Three guidelines recommend that "low-risk" women in spontaneous labor at term should hold determination over what they ingest in labor. No recommendations with respect to assessment and management of hydration for women undergoing induction of labor were found.

DISCUSSION

Despite the increasing use of intravenous fluid as an adjunct to oral intake to maintain maternal intrapartum hydration, there is limited evidence and, subsequently, guidelines to determine best practice in this area. How hydration is assessed was also largely absent from general intrapartum care guidelines, further perpetuating potential clinical variation in this area.

CONCLUSION

There is an absence of guidelines specific to the assessment and management of maternal hydration during labor and birth, despite its importance in ensuring labor progress and safe care.

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.

Effect of a carbohydrate-rich beverage on rate of cesarean delivery in primigravidae with epidural labor analgesia: a multicenter randomized trial

BACKGROUND

Labor represents a period of significant physical activity. Inefficient energy supply may delay labor process and even lead to cesarean delivery. Herein we investigated whether ingestion of a carbohydrate-rich beverage could reduce cesarean delivery in laboring women with epidural analgesia.

METHODS

This multicenter randomized trial was conducted in obstetrician-led maternity units of nine tertiary hospitals in China. Primigravidae with single term cephalic pregnancy who were preparing for vaginal birth under epidural analgesia were randomized to intake a carbohydrate-rich beverage or commercially available low-carbohydrate beverages during labor. The primary outcome was the rate of cesarean delivery. Secondary outcomes included maternal feeling of hunger, assessed with an 11-point scale where 0 indicated no hunger and 10 the most severe hunger, and maternal and neonatal blood glucose after childbirth.

RESULTS

Between 17 January 2018 and 20 July 2018, 2008 women were enrolled and randomized, 1953 were included in the intention-to-treat analysis. The rate of cesarean delivery did not differ between the two groups (11.3% [111/982] with carbohydrate-rich beverage vs. 10.9% [106/971] with low-carbohydrate beverages; relative risk 1.04, 95% CI 0.81 to 1.33; p = 0.79). Women in the carbohydrate-rich beverage group had lower subjective hunger score (median 3 [interquartile range 2 to 5] vs. 4 [2 to 6]; median difference - 1; 95% CI - 1 to 0; p < 0.01); their neonates had less hypoglycemia (1.0% [10/968] vs. 2.3% [22/956]; relative risk 0.45; 95% CI 0.21 to 0.94; p = 0.03) when compared with those in the low-carbohydrate beverage group. They also had higher rates of maternal hyperglycemia (6.9% [67/965] vs. 1.9% [18/953]; p < 0.01) and neonatal hyperglycemia (9.2% [89/968] vs. 5.8% [55/956]; p < 0.01), but none required special treatment.

CONCLUSIONS

For laboring primigravidae with epidural analgesia, ingestion of a carbohydrate-rich beverage compared with low-carbohydrate beverages did not reduce cesarean delivery, but relieved maternal hunger and reduced neonatal hypoglycemia at the expense of increased hyperglycemia of both mothers and neonates. Optimal rate of carbohydrate supplementation remains to be determined.

TRIAL REGISTRATION

www.chictr.org.cn ; identifier: ChiCTR-IOR-17011994 ; registered on 14 July 2017.

Factors associated with blood cord unit bankability: an analysis of a 15-year-long case series

Blood banking is a long and complex process requiring an accurate screening of potential donors and high-quality control systems. Previous studies in literature investigated factors potentially determining a higher cell levels with the aim of optimizing donors' selection and improving banking process. This study aims to identify factors associated with the concentration of stem cells in umbilical cord blood, so increasing the probability of bankability, focusing on the possible implications in terms of obstetric and resources management. This is a retrospective study conducted in the Obstetric Units of two Italian Hospitals in Montebelluna and Castelfranco Veneto. Study has been conducted on cord blood units banked between 1999 and 2015. Data on medical histories and clinical characteristics of mother and baby have been retrieved via a retrospective examination of medical records. A total of 869 cord blood units were studied. At multivariable analysis, in agreement with literature, birthweight and placental weight have been found to be associated with higher concentration of total nucleated cells. As additional factor, amount of fluid infused was associated with cord blood units' count. This study is the first one to clearly identify the role of fluid infusion on cord blood units' counts in addition to placental weight and delivery. Some non-modifiable features can help in predicting bankability from pre-natal aspects to factors more related with obstetric management is suggested.

Hyponatraemia reversibly affects human myometrial contractility. An in vitro pilot study

Background

In a previous study we found a significant correlation between dystocia and hyponatraemia that developed during labour. The present study examined a possible causal relationship. In vitro studies often use area under the curve (AUC) determined by frequency and force of contractions as a measure of myometrial contractility. However, a phase portrait plot of isometric contraction, obtained by plotting the first derivate of contraction against force of contraction, could indicate that bi-or multiphasic contractions might be less effective compared to the smooth contractions.

Material and methods

Myometrial biopsies were obtained from 17 women undergoing elective caesarean section at term. Each biopsy was divided into 8 strips and mounted isometrically in a force transducer. Seven biopsies were used in the first part of the study when half of the strips were immersed in the hyponatraemic study solution S containing Na⁺ 120 mmol/L and observed for 1 hour, followed by 1 hour in normonatraemic control solution C containing Na⁺ 136 mmol/L, then again in S for 1 hour, and finally 1 hour in C. The other half of the strips were studied in reverse order, C-S-C-S. The remaining ten biopsies were included in the second part of the study. Response to increasing doses of oxytocin (OT) in solutions S and C was studied. In the first part of the study we calculated AUC, and created phase portrait plots of two different contractions from the same strip, one smooth and one biphasic. In both parts of the study we registered frequency and force of contractions, and described appearance of the contractions.

Results

First part of the study: Mean (median) contractions per hour in C: 8.7 (7.6), in S 14,3 (13). Mean (SD) difference between groups 5.6 (4.2), p = 0.018. Force of contractions in C: 11.8 (10.2) mN, in S: 10.8 (9.2) mN, p = 0.09, AUC increased in S; p = 0.018. Bi-/multiphasic contractions increased from 8% in C to 18% in S, p = 0.001. All changes were reversible in C. Second part of the study: Frequency after OT 1.65 x 10−⁹ M in C:3.4 (2.9), in S: 3.8 (3.2), difference between groups: p = 0.48. After OT 1.65 x 10−⁷ M in C: 7.8 (8.9), increase from previous OT administration: p = 0.09, in S: 8.7 (9.0), p = 0.04, difference between groups, p = 0.32. Only at the highest dose of OT dose was there an increase in force of contraction in S, p = 0.05, difference between groups, p = 0.33. Initial response to OT was more frequently bi/multiphasic in S, reaching significance at the highest dose of OT(1.65 x 10−⁷ M), p = 0.015. when almost all contractions were bi/multiphasic.

Conclusion

Hyponatraemia reversibly increased frequency of contractions and appearance of bi-or multiphasic contractions, that could reduce myometrial contractility. This could explain the correlation of hyponatraemia and instrumental delivery previously observed. Contractions in the hyponatraemic solution more frequently showed initial multiphasic contractions when OT was added in increasing doses. Longer lasting labours carry the risk both of hyponatraemia and OT administration, and their negative interaction could be significant. Further studies should address this possibility.

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

There is a lack of consensus in the international scientific community with respect to the most suitable hydration strategies when attending nulliparous women during low-risk births. This paper describes the protocol for a randomized controlled trial to compare two hydration strategies and their influence on maternal and neonatal morbidity. The study population consists of nulliparous women admitted to the obstetrics department of a University Hospital. The women are being randomized into two groups: the "optimal hydration" group, which will be guaranteed 300 ml/hr liquids (crystalloids and bottled mineral water) with a minimum diuresis of 35 ml/hr; and the "variability in hydration" group, which will receive intravenous (alternating normal saline, Ringer's lactate solution, glucose, or Voluven®) and clear (bottled mineral water or isotonic drinks [Aquarius®]) liquids, without any established perfusion rate, and without established minimum diuresis. Outcomes for mothers include duration of labor, cesarean section, fever, and dehydration. Outcomes for newborns are respiratory distress, hypoglycemia, hyponatremia, jaundice, weight loss over 48 hr, and breastfeeding difficulties. Analysis will be per-protocol. Administering optimal hydration may improve health and safety for mothers and their newborn and reduce maternal and neonatal morbidity. The study is registered at www.clinicaltrials.gov. The project received funding by the Ministry of Health of Spain and is approved by the Research Ethics Committee.

The effects of intravenous dextrose 5%, Ringer's solution, and oral intake on the duration of labor stages in nulliparous women: a double-blind, randomized, controlled trial

Background and objectives: Childbirth consists of a three-stage period beginning with uterine contractions and ending in the expulsion of the placenta. The present study was conducted to compare the effects of Ringer's solution, dextrose solution 5%, and oral intake on the duration of total labor and labor stages (primary outcome) and the frequency of oxytocin administration and prolonged labor (secondary outcome) in nulliparous women with spontaneous vaginal delivery.Materials and methods: The present randomized clinical trial was conducted on 201 nulliparous women in labor assigned with a randomized block design to three groups, each receiving either Ringer's solution plus oral fluids, dextrose solution 5% solution plus oral fluids or oral fluids alone. The solutions were intravenously administered at a rate of 125 ml/h in the groups receiving the solutions and the subjects in the oral fluids group could consume liquids of their choice (water, orange juice, and apple juice). The duration of total labor and labor stages (the active stage, the second, and third stages of labor) were recorded by the researcher in minutes. Furthermore, the frequency of oxytocin administration and prolonged labor were recorded by the researcher by using a checklist. Data were analyzed using the Kruskal-Wallis test, Mann-Whitney's U-test, chi- square test and Fisher exact test.Results: The mean (±SD) duration of total labor was 301.2 (±50.0) minutes in the Ringer group, 171.9 (±36.4) in the dextrose 5% group, and 524.8 (±103.4) in the oral fluids group, suggesting a statistically significant intergroup difference (p < .001). The mean (±SD) duration of the active stage of labor was 276.7 (±91.3) minutes in the Ringer group, 150.6 (±78.5) in the dextrose 5% group, and 302.4 (±136.8) in the oral fluids group, suggesting a statistically significant intergroup difference (p < .001). A significant difference was also observed between the three groups in terms of the duration of the third stage of labor (p < .001); however, no significant differences were observed in terms of the duration of the second stage of labor (p = .058). Furthermore, a significant difference was observed between the three groups in terms of the need for oxytocin administration (p ≤ .001) and the frequency of prolonged labor (p = .001).Conclusion: The results suggest that the consumption of dextrose solution by nulliparous women reduces the duration of labor, the need for oxytocin administration and the frequency of prolonged labor compared to when Ringer's solution and oral fluids are used.

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.

Maternal and neonatal hyponatremia during labor: a case series

BACKGROUND

Hyponatremia during labor and delivery may result in severe maternal and neonatal sequelae. Our aim was to describe the direct effect of hyponatremia in labor on pregnancy outcome.

METHODS

A case series of parturients diagnosed with hyponatremia during labor and their neonates. Clinical presentation, laboratory workup, and maternal and neonatal outcomes are presented.

RESULTS

Four parturients and their corresponding six neonates were diagnosed with hyponatremia. Of these, two cases were caused by water intoxication and two were preeclampsia induced. While two were identified due to maternal or neonatal symptoms, two were diagnosed by routine laboratory testing. In all cases, low maternal sodium resulted in similarly low neonatal sodium. Neonatal symptoms included respiratory distress syndrome (RDS), lethargy, and jaundice.

CONCLUSION

Psychogenic drinking during labor and preeclampsia may predispose to maternal hyponatremia, resulting in neonatal hyponatremia. Early recognition and treatment can prevent further maternal deterioration and adverse neonatal sequelae.

Oxytocin Use in Labor: Legal Implications

Oxytocin is one of the most commonly used medications in obstetrics and has been associated with claims of negligence in cases of adverse outcomes. Errors involving intravenous oxytocin administration for induction or augmentation of labor are most commonly dose related and include failure to avoid or treat tachysystole or failure to asses or treat a fetal heart rate pattern indicative of disruption in oxygenation. Clinicians should be knowledgeable regarding pharmacokinetics of oxytocin and the effect of uterine contractions on fetal oxygenation as well as safe titration of oxytocin to achieve the desired effect while minimizing harm.

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.

Maternal pulse pressure at admission is a risk factor for fetal heart rate changes after initial dosing of a labor epidural: a retrospective cohort study

OBJECTIVE

To examine low maternal admission pulse pressure (PP) as a risk factor for new onset postepidural fetal heart rate (FHR) abnormalities.

STUDY DESIGN

Retrospective cohort study of nulliparous, singleton, vertex-presenting women admitted to labor and delivery after 37 0/7 weeks that received an epidural during labor. Women with a low admission PP were compared with those with a normal admission PP. The primary outcome was new onset FHR abnormalities defined as recurrent late or prolonged FHR decelerations in the first hour after initial dosing of a labor epidural.

RESULTS

New onset FHR abnormalities, defined as recurrent late decelerations and/or prolonged decelerations, occurred in 6% of subjects in the normal PP cohort compared with 27% in the low PP cohort (odds ratio, 5.6; 95% confidence interval, 2.1-14.3; P < .001). A multivariate logistic regression analysis generated an adjusted odds ratio of 28.9 (95% confidence interval, 3.7-221.4; P < .001).

CONCLUSION

New onset FHR abnormalities after initial labor epidural dosing occur more frequently in women with a low admission PP than those with a normal admission pulse. Admission PP appears to be a novel predictor of new onset postepidural FHR abnormalities.

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.

A randomized controlled trial of the effect of intrapartum intravenous fluid management on breastfed newborn weight loss

OBJECTIVE

To determine the effect of conservative versus usual intrapartum intravenous (IV) fluid management for low-risk women receiving epidural analgesia on weight loss in breastfed newborns.

DESIGN

A randomized controlled trial.

SETTING

A tertiary perinatal center in a large urban setting.

SAMPLE

Women experiencing uncomplicated pregnancies who planned to have epidural analgesia and to breastfeed.

METHODS

Healthy pregnant women were randomized to receive an IV epidural preload volume of <500 mLs continuing at an hourly rate of 75-100 mL/h (conservative care) or an epidural preload volume of ≥500 mLs and an hourly rate >125 mL/h (usual care). The primary study outcome was breastfed newborn weight loss >7% prior to hospital discharge. Secondary study outcomes included breastfeeding exclusivity, referral to outpatient breastfeeding clinic support, and delayed discharge. Other outcomes were admission to the neonatal intensive care unit and cord blood pH <7.25.

RESULTS

Two hundred women participated (100 in the conservative care and 100 in the usual care groups). Forty-eight of 100 infants in the usual care group and 44 of the 100 infants in the conservative care group lost >7% of their birth weight prior to discharge, p < 0.52 RR 0.92 [0.68-1.24].

CONCLUSION

A policy of restricted IV fluids did not affect newborn weight loss. Women and their care providers should be reassured that the volumes of IV fluid <2500 mLs are unlikely to have a clinically meaningful effect on breastfed newborn weight loss >7%. Exploratory analyses suggest that breastfed newborn weight loss increases when intrapartum volumes infused are >2500 mLs. Care providers are encouraged to consider volumes of IV fluid infused intrapartum as a factor that may have contributed to early newborn weight loss in the first 48 h of life.

A randomized controlled trial comparing parenteral normal saline with and without 5% dextrose on the course of labor in nulliparous women

OBJECTIVE

The objective of this study was to compare intravenous normal saline with and without 5% dextrose on the course of labor in nulliparous women in active phase of spontaneous labor.

STUDY DESIGN

In a randomized controlled trial, term, nulliparous women with singleton pregnancy in active labor were randomized into one of two groups receiving either normal saline or normal saline alternating with 5% dextrose at rate of 175 ml/h. The primary outcome was total length of labor from onset of study fluid in vaginally delivered women. Maternal and neonatal outcomes were also analyzed.

RESULTS

Of 250 women enrolled, in vaginally delivered subjects, there was significant difference in the duration of labor (p=0.0) and prolonged labor (p=0.01), with favorable results for women in 5% dextrose alternating with normal saline. No statistically significant differences were observed in the cesarean section rates between the groups. The cord pH was significantly higher in neonates born to women in 5% dextrose alternating with normal saline infusion as compared to normal saline alone (p=0.01), however, no neonate in the study had acidemia.

CONCLUSION

Administration of a 5% dextrose solution alternating with normal saline is a better parenteral fluid for significantly decreasing duration of labor in term vaginally delivered nulliparous women in spontaneous active labor as compared to normal saline alone.

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.

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

PURPOSE

To compare the effects of two different regimens of intravenous hydration and oral hydration on the duration of active labor.

METHODS

Two hundred and ninety-three low risk term primigravida in active labor were randomized into three groups. The first group had 99 patients who received oral fluids only, the second group of 98 patients received intravenous Ringer lactate at the rate of 125 ml/h (IV 125 ml) and the third group had 96 patients who received intravenous Ringer lactate at a rate of 250 ml/h (IV 250 ml). Amniotomy and oxytocin administration were allowed according to the physician's discretion.

RESULTS

The mean duration of labor in the oral fluid group was 391, 363 min in the 125 ml/h group and 343 min in the 250 ml/h group, P = 0.203. The incidence of prolonged labor more than 12 h in the oral fluid group was 7.1% in the oral fluid group, 4.1% in the 125 ml/h group and 3.1% in the 250 ml/h group, P = 0.402. The oxytocin requirement was 37% in the oral group, 32% in the 125 ml/h group and 33% in the 250 ml/h group, P = 0.68. There was a statistically significant reduction in the incidence of vomiting in patients receiving intravenous hydration, i.e. 24.2% in the oral group, 11.2% in the 125 ml/h group and 6.3% in the 250 ml/h group, P = 0.001. There was no difference in the mode of delivery, maternal or neonatal complications between the three groups.

CONCLUSION

This study establishes a trend towards decreased incidence of prolonged labor and less vomiting in patients receiving intravenous hydration.

Intrauterine Resuscitation During Labor: Review of Current Methods and Supportive Evidence

When the fetal heart rate pattern is suggestive of fetal compromise during labor, various methods to promote fetal well-being are traditionally initiated. They include maternal repositioning, reduction of uterine activity, an intravenous fluid bolus, oxygen administration, correction of maternal hypotension, amnioinfusion, and alteration of second-stage labor pushing efforts. Although these intrauterine resuscitation techniques are commonly used, and in some cases considered standard care, supportive data could be more robust. Nevertheless, there is enough evidence to suggest they are beneficial to the fetus and there is minimal risk of harm when used with clinical common sense. Until more data are available, it seems reasonable to err on the side of fetal safety by using these techniques when appropriate, based on the specific fetal heart rate pattern.

"Active labor" duration and dilation rates among low-risk, nulliparous women with spontaneous labor onset: a systematic review

INTRODUCTION

Laboring women are often admitted to labor units under criteria that are commonly associated with the onset of active-phase labor (i.e., cervical dilatation of 3-5 cm in the presence of regular contractions). Beginning with these criteria through complete dilatation, this systematic review describes labor duration and cervical dilation rates among low-risk, nulliparous women with spontaneous labor onset.

METHODS

Studies published in English (between 1990 and 2008) were identified via MEDLINE and CINAHL searches. Data were abstracted and weighted "active labor" durations (i.e., from 3-5 cm through complete dilatation) and linear dilation rates were calculated.

RESULTS

Eighteen studies (n = 7009) reported mean "active labor" duration. The weighted mean duration was 6.0 hours, and the calculated dilation rate was 1.2 cm per hour. These findings closely parallel those found at the median. At the statistical limits, the weighted "active labor" duration was 13.4 hours (mean + 2 standard deviations) and the dilation rate was 0.6 cm per hour (mean - 2 standard deviations).

DISCUSSION

These findings indicate that nulliparous women with spontaneous labor onset have longer "active" labors and therefore slower dilation rates than are traditionally associated with active labor when commonly used criteria are applied as the starting point. Revision of existing active labor expectations and/or criteria used to prospectively identify active phase onset is warranted.

A randomized, double-blinded, controlled trial comparing parenteral normal saline with and without dextrose on the course of labor in nulliparas

OBJECTIVE

The objective of the study was to compare intravenous normal saline with and without dextrose on the course of labor in nulliparae.

STUDY DESIGN

In a double-blinded, controlled trial, term, nulliparae with singletons in active labor were randomized into 1 of 3 groups receiving either normal saline (NS), NS with 5% dextrose (D5NS), or NS with 10% dextrose (D10NS) at 125 mL/h. The primary outcome was total length of labor from onset of study fluid in vaginally delivered subjects. Maternal and neonatal outcomes were also analyzed.

RESULTS

Of 300 subjects enrolled, 289 met inclusion criteria and completed the study. In vaginally delivered subjects, significant differences were noted in the second stage (P = .01) and total length of labor (P = .02). No significant differences were observed in the cesarean section rates between the groups (P = .21). No differences were noted in maternal or neonatal secondary outcomes.

CONCLUSION

Administration of a dextrose solution, regardless of concentration, was associated with a shortened labor course in term vaginally delivered nulliparae subjects in active labor.

Hyponatremia complicating labour--rare or unrecognised? A prospective observational study

Objective

The aim of this study was to investigate the occurrence of hyponatraemia following delivery, with a hypothesis that hyponatraemia has a high prevalence in labouring women.

Design

Prospective observational study.

Setting

Consultant-led delivery suite in County Hospital, Kalmar, Sweden.

Sample

A total of 287 pregnant women at term (37 full gestational weeks).

Methods

Oral fluids were allowed during labour. Blood samples were collected on admission, after delivery, and from the umbilical artery and vein.

Main outcome measure

Hyponatraemia defined as plasma sodium ≤130 mmol/l after delivery.

Results

Hyponatraemia was found in 16 (26%) of the 61 mothers who received more than 2500 ml of fluid during labour. Two-thirds of fluids were orally ingested. Decrease in plasma sodium concentration during labour correlated with duration of labour and the total fluid volume administered. Analysis by multivariate logistic regression showed that hyponatraemia was significantly correlated with fluid volume (P < 0.001) but not with oxytocin administration or epidural analgesia. Hyponatraemia correlated significantly with prolonged second stage of labour, instrumental delivery, and emergency caesarean section for failure to progress (P = 0.002).

Conclusions

Hyponatraemia is not uncommon following labour. Tolerance to a water load is diminished during labour; therefore, even moderate fluid volumes may cause hyponatraemia. Women should not be encouraged to drink excessively during labour. Oral fluids, when permitted, should be recorded, and intravenous administration of hypotonic fluids should be avoided. When abundant drinking is unrecognised or intravenous fluid administration liberal, life-threatening hyponatraemia may develop. The possibility that hyponatraemia may influence uterine contractility merits further investigation.

Oxytocin: new perspectives on an old drug

Oxytocin is the drug most commonly associated with preventable adverse perinatal outcomes and was recently added by the Institute for Safe Medication Practices to a small list of medications "bearing a heightened risk of harm," which may "require special safeguards to reduce the risk of error." Current recommendations for the administration of this drug are vague with respect to indications, timing, dosage, and monitoring of maternal and fetal effects. A review of available clinical and pharmacologic data suggests that specific, evidence-based guidelines for the intrapartum administration of oxytocin may be derived from available data. If implemented, such practices may reduce the likelihood of patient harm. These suggested guidelines focus on limited elective administration of oxytocin, consideration of strategies that have been shown to decrease the need for indicated oxytocin use, reliance on low-dose oxytocin regimens, adherence to specific semiquantitative definitions of adequate and inadequate labor, and an acceptance that once adequate uterine activity has been achieved, more time rather than more oxytocin is generally preferable. The use of conservative, specific protocols for monitoring the effects of oxytocin on mother and fetus is likely not only to improve outcomes but also reduce conflict between members of the obstetric team. Implementation of these guidelines would seem appropriate in a culture increasingly focused on patient safety.