Are IV Fluids Necessary During Labor?

The latest national survey from the United States (U.S.) of childbirth experiences reported that most people (62%) received continuous “drip” intravenous (IV) fluids during labor (Declercq et al. 2014). A more recent survey of California hospital births found that 76% of people received IV fluids during labor with midwives versus 87% with an obstetrician attendant (Declercq et al. 2020).

Labor is considered by many to be a demanding exercise, but many people in the U.S. (and other countries) are not allowed to eat or drink (called “NPO,” nil per os, or “nothing by mouth”) during labor. Because it is necessary to stay hydrated during labor, IV fluids are usually administered.  However, if you read the Evidence Based Birth® Signature Article on Eating and Drinking During Labor, you will see that the practice of forbidding food and drink, while common, is not evidence-based.

“Nothing by mouth” during labor originated in the 1940s and is based on doctors’ fear that a person will inhale (aspirate) stomach contents while under general anesthesia for an emergency Cesarean. However, the increase in the use of epidurals and advances in surgery and anesthesia have made aspiration almost unheard of today. The American College of Nurse Midwives, World Health Organization, National Institute for Health and Care Excellence guidelines in the United Kingdom, and the Society of Obstetricians and Gynecologists guidelines in Canada all recommend that people be able to choose whether or not they want to eat and drink during labor.

If people can choose to eat or drink during labor, then are IV fluids necessary?

What Are Intravenous (IV) Fluids?

Many hospitalized patients receive IV fluid therapy to maintain adequate hydration when oral (by mouth) fluids are restricted. The three most common IV solutions in labor are normal saline, Ringer’s lactate, and dextrose solutions (Dawood et al. 2013). For how common they are, surprisingly little research has been done to compare the different types of IV fluids used during labor.

When IV fluids are medically necessary, the type of solution and the amount infused should be determined on an individual basis (ACOG, 2019). Normal saline and Ringer’s lactate are isotonic solutions, meaning that they allow water to flow freely at a cellular level, without causing cells to swell or shrink.

Dextrose is a type of sugar from corn or wheat that is almost identical to glucose. When dextrose is dissolved in water, this is also an isotonic solution, but it doesn’t act as one inside the body. It provides calories that the body can use for energy, but as the sugar is used, the solution becomes hypotonic and pulls water into the cells.

A trial in 1995 compared dextrose solution and normal saline for oxytocin administration and found that the dextrose solution caused blood sodium (salt) levels to fall too low in mothers and babies (Stratton et al. 1995). Nowadays, dextrose solutions are commonly mixed with normal saline or Ringer’s lactate to increase safety.

Ketosis means that there are raised levels of ketones that can be measured in blood and urine. During times of starvation or carbohydrate restriction, the body burns fat for energy, resulting in the release of ketones. Ketosis is a natural state that allows the body to use fat for energy. However, if monitoring indicates very low levels of blood sugar during labor, oral fluids with sugar or IV fluids with dextrose can be used to correct the imbalance. People with gestational diabetes or pre-pregnancy diabetes benefit from close monitoring of blood sugar levels during labor. Please read the Evidence Based Birth® Signature Article on Eating and Drinking During Labor for more information on guidelines for helping people with diabetes maintain a healthy blood sugar during labor.

Fluid volume overload, also known as hypervolemia, can happen when there is too much fluid in the blood. With hypervolemia, excess fluid can collect in the lungs and other tissues, and the heart has to work harder to pump the extra fluid around the body (Carvalho and Mathias 1994). Fluid overload is more likely with IV fluids than oral fluids because the fluid goes directly into the bloodstream, instead
of traveling through the stomach and intestines first, thereby overriding a healthy body’s ability to maintain fluid balance. Overload is less likely to happen in young people with healthy kidneys that can process extra IV fluids by getting rid of them through urine, and healthy hearts that can easily pump the extra blood volume (Floss and Borthwick 2008).

What Is the Evidence on IV Fluids During Labor?

Three studies, called meta-analyses, have combined data from many similar studies on IV fluids during labor. In 2013, Cochrane reviewers combined nine randomized trials and looked at results from 1,617 people (Dawood et al. 2013). The researchers were interested in whether or not routine IV fluids could shorten the length of labor. They also looked at how IV fluids might affect birth outcomes like Cesareans, operative births (assistance with forceps or vacuum during second stage), number of babies admitted to the NICU, or Apgar scores.

The second meta-analysis, which we will refer to as the 2017 meta-analysis, included seven randomized trials with a total of 1,215 people (Ehsanipoor et al. 2017). These researchers also studied the relationship between IV fluids and birth outcomes but they were mostly interested in whether or not an increased rate of IV fluids could safely reduce the Cesarean rate.

Finally, Riegel et al. (2018) conducted a meta-analysis of 16 randomized trials (with 2,503 participants) to examine whether dextrose IV fluids reduced the length of the first stage of labor.

All of the study participants in these meta-analyses were low-risk (as defined by the individual trials). Dawood and Ehsanipoor only included participants in spontaneous labor (labor that started on its own) and giving birth for the first time. Riegel included first-time birthing people and people who have given birth before who were in spontaneous or induced labor.

None of these studies reported on satisfaction or dehydration level, nor did they measure breastfeeding/chestfeeding rates or the effect of the IV fluids on the newborn’s early weight loss.

IV Fluids + Oral Fluids vs. Oral Fluids Alone

Very few researchers have ever compared IV fluids versus oral fluids alone. This in itself is very revealing! IV fluids have become so common during labor that when they are studied, it’s usually to compare one type or rate of fluid to another. Only three times in history have researchers ever compared IV fluids to oral fluids, and in all three studies, people in the IV fluids groups were also permitted to drink oral fluids.

In the first trial, 293 people in labor were randomly assigned to one of three groups: oral fluids alone (plain water and coconut water), oral fluids plus IV fluids of Ringer’s lactate at 125 mL/hr, or oral fluids plus IV fluids at 250 mL/hr (Kavitha et al. 2012). There were no differences between the groups in regards to length of labor (first stage, second stage, or total length), Cesareans, augmentations, or any other complications. There was a lower chance of vomiting with more IV fluids (6% vomiting in the 250 mL group, 11% in the 125 mL group, and 24% in the oral fluid group). There were no cases of fluid overload in the lungs, also known as pulmonary edema.

This was one of several studies in the meta-analyses that measured pulmonary edema; however, other signs and symptoms of fluid overload were not measured. For example, researchers did not measure whether people experienced swelling in the arms, legs, and chest. This swelling, called peripheral edema, can be painful and is a sign of fluid volume overload.

In the second study, 120 people were randomly assigned to either oral fluids alone (water or soda), or to oral fluids plus IV fluids of Ringer’s lactate at 60 mL/hr, 120 mL/hr, or 240 mL/hr (Direkvand-Moghadam and Rezaeian 2012). The researchers found longer first and second stages of labors in the people who had not received IV fluids. Also, Pitocin® augmentation was used more frequently in the group with no IV fluids. They found no differences between groups with rates of Cesarean, vomiting, or low Apgar scores in the newborn. The authors didn’t report on any markers of fluid overload.

When these two studies were combined, the Cochrane researchers found that people who had received IV fluids plus access to oral fluids had shorter labors (by about 30 minutes) compared to those who took oral fluids alone (Dawood et al. 2013). There was no difference in Cesareans or Apgar scores. 

It’s important to note that in both trials, the people receiving IV fluids were also permitted to take in oral fluids. In the first trial, they reported the average amount of total fluid intake received by group: 896 mL for those taking oral fluids alone, 727 mL for those receiving IV fluids of 125 mL/hr, and 1,326 mL for those receiving IV fluids of 250 mL/hr. The oral fluids alone group experienced the greatest fluid loss due to vomiting. We contacted the authors for more information and found out that the oral intake among the people in the IV fluids groups was not documented because they drank so little, so the IV fluids group totals essentially refer to IV fluid intake alone (Personal Communication, Dr. Jiji Mathews, 2016). The second trial didn’t report the total amount of fluid received in each group, but, interestingly, they did determine that the IV fluids groups drank just as much fluid orally as the oral fluids only group.

So, the people who took in more fluids had shorter labors by about 30 minutes when the studies were combined. This suggests that mild dehydration could contribute to slightly longer labors. That people receiving IV fluids in the second trial also chose to take in oral fluids in the same amounts as the oral fluids only group suggests that people without IV fluids may need support and encouragement to drink enough to stay hydrated during labor. It might not be enough to rely on feelings of thirst, when the laboring person is distracted by the work of labor.

A third trial, too recent to be included in the Cochrane review, compared Ringer’s solution plus oral fluids, 5% dextrose solution plus oral fluids, and oral fluids alone (Ahadi Yulghunlu et al. 2020). The researchers were interested in whether the type of hydration affected the length of labor in low-risk people giving birth for the first time.

The study participants were all in spontaneous labor and at least 4 cm dilated. They were randomly assigned to three groups (67 people in each). The people receiving the IV fluids were given a rate of 125 ml/hr. Subjects were blinded to the type of IV fluid, along with the researcher. Everyone, regardless of group assignment, was free to drink liquids (water, orange juice or apple juice).

The study found that people receiving IV fluids with dextrose had significantly shorter labors, on average, compared to the other groups. The average length of total labor was 525 minutes with oral fluids alone, 301 minutes with Ringer’s solution + oral fluids, and 172 minutes with dextrose solution + oral fluids. They also observed a significant reduction in the length of the active stage of labor and the third stage of labor with dextrose solution, but no difference in the second stage of labor. In addition, the people in the dextrose group used less Pitocin® and had a lower rate of prolonged labor (active labor >12 hours).

The study did not report the amount of oral fluids consumed by each group, or the amount of water they drank versus carbohydrate-containing fluids. If the oral fluids only group drank mostly water in small amounts, the outcome might have been different then if they had taken more fluids, especially oral carbohydrates. So, it’s possible that the benefits seen with dextrose IV fluids could also be achieved with a sufficient volume of oral carbohydrate-containing fluids. More research is necessary to gain a better understanding.

Comparing IV Fluids at Different Rates

Next, the Cochrane review looked at people receiving 125 mL/hr fluids vs. 250 mL/hr fluids, in addition to being able to drink freely.

This category includes the previous two studies and adds one more. In the additional study, researchers randomly assigned 80 people in labor to receive Ringer’s lactate at 250 mL/hr or “usual care” (Coco et al. 2010). “Usual care” meant that the person would receive IV fluids if the provider thought they were needed for medical reasons. The people in the IV fluids group received an average of 2,660 ml of IV fluids. Those in the “usual care” group ended up receiving an average of 1,627 mL of IV fluids over the course of their labor, which worked out to approximately 125 mL/hr. People in both groups were allowed to drink as much as they desired (water, juice, soda), and both groups drank similar amounts. There were no differences between groups with regard to total labor length, length of each stage of labor, Cesareans, augmentations, or any other outcome measured. The authors did not mention anything about measuring markers of fluid volume overload in the mothers or babies, so we contacted the primary author, who confirmed that markers of fluid volume overload were not measured.

When these three trials were combined, the Cochrane researchers found shorter labors (by 24 minutes) in people receiving IV fluids at 250 mL/hr and drinking freely than those receiving IV fluids at 125 mL/hr and drinking freely. They found no difference in Cesareans or any other outcome measured. This is more evidence that people without IV fluids or receiving fluids at a rate of less than 250 mL/hr may benefit from active encouragement to drink enough fluids for adequate hydration or face a slight increase in the length of labor.

The 2017 meta-analysis included one trial that was too recent to be included in the Cochrane review (Edwards et al. 2014; Ehsanipoor et al. 2017). They did not find any benefits from increased IV or oral hydration. The authors randomly assigned people to receive Ringer’s lactate with 5% dextrose at 25 mL/hr (101 people), 125 mL/hr (105 people), or 250 mL/hr (105 people). The 25 mL/hr group could drink freely, but the other two groups were only allowed to have ice chips. They found no differences as far as labor duration, augmentation, Cesareans, Apgar scores, or any other outcome assessed. There were no cases of pulmonary edema.

Nothing by Mouth and IV Fluids at Different Rates

(Is a “nothing by mouth” policy and IV fluids at 125 mL/hr a recipe for dehydration? YES)

Four trials compared different rates of IV fluids (125 mL/hr versus 250 mL/hr) in people who either had zero oral intake, or ice chips only, or occasional sips of water (Garite et al. 2000; Alavi et al. 2005; Eslamian et al. 2006; Maderia et al. 2007). This means that none of the participants in these studies were allowed to drink freely, similar to many hospital environments today.

When the results from these trials were combined, the Cochrane reviewers found longer labors (by about 90 minutes) in the people who received 125 mL/hr IV fluids versus 250 mL/hr. They also found a higher risk of Cesarean for any indication in the group that received IV fluids at 125 mL/hr. There were no differences detected in operative vaginal birth and not enough information to draw conclusions about fluid overload.

The findings of the 2017 meta-analysis of seven trials were consistent with the four trials pooled in the Cochrane review. The 2017 meta-analysis found that people who received IV fluids at 125 mL/hr versus 250 mL/hr had longer labors by about one hour and a 30% higher risk of Cesarean for any indication. The effects observed in the Cochrane review were larger than those in the 2017 meta-analysis, perhaps because the Cochrane estimate only describes the trials with restrictions on oral intake, while the 2017 meta-analysis estimate also includes some trials with unrestricted oral intake. The authors of the 2017 meta-analysis estimate that treating 18 laboring people with IV fluids at a rate of 250 mL/hr instead of 125 mL/hr could prevent one Cesarean (Ehsanipoor et al. 2017). However, this finding cannot be generalized to those who are allowed to drink freely, since most people included in their review were under strict oral intake restrictions.

What Is the Evidence on Dextrose IV Fluids?

Since muscle performance during prolonged exercise is improved with carbohydrate replacement, researchers think that carbohydrate replacement during childbirth may help the uterus contract and speed up labor (Riegel et al. 2018).

Riegel et al. (2018) is the first meta-analysis to study randomized trials specifically comparing IV fluids with dextrose versus no dextrose. They included sixteen randomized trials with a total of 2,503 participants. None of the participants had diabetes, preeclampsia, or newborns with intrauterine growth restriction. Studies were included regardless of oral intake restrictions. Only one of the studies allowed participants to eat and drink during labor as desired.

Most of the studies in the dextrose group used 5% dextrose (12 studies); four studies also gave at least some of their participants 2.5% or 10% dextrose. In the no dextrose (control) group, the studies used 0.9% normal saline solution or Ringer’s lactate. Only one of the studies in the no dextrose group included participants (16 people) who did not receive any IV fluids. Their access to oral fluids, however, was not reported.

The IV fluids were given at varying rates, from 20-300 mL/hr, and they were usually started during “active labor” (as defined by the individual studies).
Laboring people randomly assigned to dextrose IV fluids had a shorter first stage of labor by about 76 minutes on average, compared to those without dextrose IV fluids. There was no difference in the length of the second stage of labor or the total length of labor between groups. However, when the authors looked only at the best quality trials, they did find a significant reduction in the total length of labor with dextrose IV fluids.

The rate of Cesareans, vaginal birth with forceps/vacuum, chorioamnionitis (an infection of the placenta and amniotic fluid), and heavy bleeding after the birth were similar between groups with and without dextrose IV fluids. There was a trend towards a lower rate of labors lasting >12 hours with dextrose IV fluids.
Among newborns, there were no significant differences in Apgar scores or admission to the NICU. Six of the 16 trials reported umbilical arterial and venous gases and they were similar between groups.

There was no significant difference in the rate of newborn hypoglycemia (low blood sugar) between groups; however, there was a trend towards an increased rate of low blood sugar with dextrose IV fluids (5.7% versus 3.2%). The authors caution that it would be wise to observe newborns exposed to dextrose-containing fluids for signs and symptoms of low blood sugar after birth until more research confirms whether the risk is clinically important (Riegel et al. 2018).

The concern is that dextrose IV fluids during labor could cause hyperglycemia (high blood sugar) in the birthing person, leading the baby to compensate by secreting more of the hormone insulin, which can result in fetal hyperinsulinemia. Then after the umbilical cord is clamped, the source of incoming glucose is cut off and the newborn can experience low blood sugar.

In conclusion, dextrose IV fluids during labor appear to shorten the first stage of labor and possibly the total length of labor. There was a trend towards a higher rate of low blood sugar in newborns who received dextrose IV fluids. Larger randomized trials are needed to further study these effects.

AJOG MFM (Maternal-Fetal Medicine), a companion title to the American Journal of Obstetrics and Gynecology, published a recent review of evidence based labor management guidelines (Alhafez and Berghella, 2020). The authors made a strong recommendation that in the setting of oral restriction, IV fluids at a rate of 250 ml/hr containing dextrose are recommended.

IV Fluids and Breastfeeding/Chestfeeding

The studies that we’ve looked at have focused mainly on the risks of dehydration and its potential to slow labor and increase the Cesarean rate. But on the other end of the spectrum, fluid overload can cause painful swelling in the birthing person and excess fluid in the newborn at birth, potentially leading to feeding complications when the newborn’s weight at birth is artificially inflated.

Newborns are often weighed within minutes of birth, and that measurement becomes the baseline for assessing weight loss in the first days of life. Clinical guidelines caution that newborn weight loss greater than 7% from birth at three to five days of age is a sign of ineffective feeding that could mean supplementation with formula is necessary (AAP, 2012). However, research suggests that some newborns are born with a fluid overload and that the resulting diuresis (correction of fluids) leads to their weight loss (Giudicelli et al. 2022).

A randomized controlled trial in 2012 was the first of its kind to examine the effect of IV fluids on newborn weight loss (Watson et al. 2012). The people in the study were all low-risk, not allowed to eat or drink, and planning to have epidurals and to breastfeed. Half of the study group (100 people) were randomly assigned to lower amounts of IV fluids which consisted of <500 mLs of fluid before receiving the epidural and an hourly rate of 75 to 100 mL/hr. Another 100 people received higher amounts of IV fluids, meaning ≥500 mLs and an hourly rate of >125 mL/hr. The average volume infused was 1,430 mLs in the lower amount group, and 2,477 mLs in the higher amount group.

In contrast to other studies that found that higher amounts of IV fluids shorten labor, this trial did not find a difference in the length of labor between the two groups. There was no difference in Cesareans or augmentation, but there were more operative vaginal births in the group receiving less IV fluids.

In this study, the authors defined excess weight loss as >7% from birth at 48 hours. When comparing the two groups, they did not find a difference in the number of breastfed newborns who experienced excess weight loss. However, they found greater weight loss in the infants born to the people who received >2,500 mLs of IV fluids. They also found a higher volume of IV fluids was given to the parents of the infants who had lost >10% of their weight. This suggests that once a parent receives around 2,500 mLs or higher of IV fluids, newborn weight loss is affected (Watson et al. 2012). The authors recommend replacing 7% weight loss with a higher percentage since almost half of the infants who were breastfeeding/chestfeeding lost 7% of their birth weight (Watson et al. 2012).

Indeed, a systematic review found that weight loss is often 7% to 8% of birth weight or greater by the third day after birth among healthy, full-term, newborns who were breastfeeding or chestfeeding (DiTomasso and Cloud, 2019). Most newborns regained lost birth weight by 14 days after birth.

Several observational studies have also looked at the relationship between IV fluids and newborn weight loss.

A recent retrospective study from France looked back at 150 records of people who gave birth to healthy babies at term after a low-risk pregnancy (Giudicelli et al. 2022). Everyone included in the study was exclusively breastfeeding at discharge. The researchers found that the newborns whose parents received 1500 mLs or more of IV fluids during labor lost significantly more weight until the third day after birth compared to those whose parents received less than 1500 mLs. The results showed an increase in the risk of losing more than 8% of the birth weight during the three first days for infants with parents who had received 1500 mLs or more of IV fluids. Longer labors, the use of synthetic oxytocin, the use of epidurals, and labors ending in Cesarean were linked to higher volume of IV fluids infused. Rather than looking at weight loss on its own, the authors recommend frequent, careful assessment of the newborn’s wellbeing before suggesting feeding supplements.

An earlier study by Chantry et al. (2010) followed 448 people through pregnancy and after birth to determine risk factors for excess weight loss in newborns (Chantry et al. 2011). This study defined excess weight loss as >10% loss of birth weight at three days old. Of the breastfed/chestfed newborns, 16-19% experienced excess weight loss. The authors looked at the predictors of excess weight loss in those babies. The only two things that independently predicted excess weight loss in newborns were increased IV fluids given to the parent during labor and delayed milk production. If parents received more than 200 mL/hr of fluids during their labor, their babies were 3.2 times more likely to experience excess weight loss at three days compared to those who received less than 100 mL/hr of fluids. The infants whose parents had taken in more fluids were also found to urinate more during the first four hours of life. More than half (58%) of the infants in this study (whose parents intended to breastfeed or chestfeed) were supplemented with formula. Reasons for supplementation were excess weight loss, along with concerns about a delay in mature milk coming in.

Other researchers have shown that reports of excess weight loss trigger a new parent’s anxiety about their milk supply, which is then associated with discontinuing breastfeeding or chestfeeding (Flaherman et al. 2016). Additionally, supplementing formula in the hospital independently predicts a shorter duration of exclusive breastfeeding or chestfeeding after hospital discharge (Semenic et al. 2008).

Figure 1 (below) shows the possible unintended consequence of receiving IV fluids during labor.

In a smaller study, a different group of researchers also found that higher amounts of fluids during labor were associated with excess weight loss in newborns (Noel-Weiss et al. 2011). The authors suggested that clinicians use the 24-hour weight—not the birth weight—as the baseline to track infant weight over time. This gives the newborn time to urinate off the excess fluid weight from the IV fluids, and get closer to what would have been their real birth weight.

In another study, researchers in Canada observed that 87% of birthing parents initiated breastfeeding/chestfeeding, but 21% of them had stopped by one month. When asked about early weaning, the parents frequently cited sore breasts/chests and painful nipples. So, the researchers conducted a small observational study to figure out if IV fluids during labor could contribute to postpartum chest swelling (Kujawa-Myles et al. 2015). Thirteen of the 17 first-time birthing people included in the study had IV fluids during birth. Participants received an average amount of 2,787 mLs of total IV fluids. Oral fluid intake was not reported. The researchers found that people who had received more IV fluids during labor reported more post-partum chest tenderness on a self-assessment scale and had more chest firmness when palpated (touched) by the researcher. However, this study had a small sample size, and neither the participants nor the researcher conducting the chest exams were blinded to each participant’s IV fluid status—which could lead to a biased result. More research is needed on this topic, and we will update this article as results come in from further studies.

The bottom line is that large amounts of IV fluids during labor can potentially harm breastfeeding/chestfeeding by contributing to excess newborn weight loss concerns and by possibly leading to painful swelling in the postpartum parent.