So, I’ve been looking forward to writing these posts on IV’s. I am a Registered Nurse, and I have put in my fair share of IV’s into people’s veins. I’ll admit it, I like to check out people’s veins in line at the grocery store. But I hate getting them myself. So when I was pregnant with my first child, I was bummed to find out that receiving IV fluids would be a standard part of my care.
But were these IV fluids necessary?
I’ll admit, I figured that since I was not allowed to eat or drink, it was better to stay hydrated than not. But I thought the rate of my IV fluids (~250 mL/hour) seemed rather high. And then I was in labor for 24 hours. And I received an epidural, which meant that I got an additional fluid bolus. But I didn’t fully experience the risks of these IV fluids until I got home from the hospital.
The next day, out of curiosity, I stepped on the scale. I had given birth to a 6.5 lb (2.95 kg) baby, plus the placenta and all that stuff. So I figured I’d be down about 10-12 pounds, right?
I had lost 3 pounds. Only three pounds.
What the heck??Instead of losing weight, I gained fluid. And lots of it. Think 24 hours times 250 mL/hour fluids. Think roughly 5-6 Liters of fluids infused into my body. Think 3+ pitting edema from my thighs to my feet (that is swelling that you can push dents into– see picture on right). Think extremely painful breast edema and engorgement that lasted for weeks, which made breastfeeding an uphill battle.
Now I never had any swelling– not even a little bit– during my entire pregnancy. So I was kind of surprised by what was going on. But I figured that maybe this was a normal physiological reaction to giving birth. And to tell you the truth, I didn’t even realize that this fluid volume overload was related to my excess IV fluid intake until several years later, when a midwife pointed out to me that my breast engorgement was probably caused by the IV fluids. Even being a nurse, I had never figured this out on my own.
The physiologic rationale for giving IV fluids is that labor is a physically demanding exercise. And many women in the United States (and other countries) are not allowed to drink or eat (NPO) during labor. However, if you read one of my earlier posts on Eating and Drinking during labor, you will see that this NPO practice is not evidence based. “Nothing by mouth” during labor is based on the clinician’s fear that a woman will need a general anaesthetic and inhale stomach contents during surgery– but the odds of this happening are less than being struck by lightning (7 events in 10 million births).
So now I am going to present to you the scientific evidence for IV fluids during labor.
Interestingly, although IV fluids during labor has been standard practice for decades, the first randomized controlled trials evaluating this practice were done in the past 10-12 years. Two studies have been done with first-time moms who were NPO (nothing by mouth) and were admitted during spontaneous labor. Garite et al. (2000) randomized 195 women to receive either 125 mL or 250 mL per hour of IV fluids. Women in the 125 mL group had a higher percentage of total labor duration greater than 12 hours (26% in the 125 mL group vs. 13% in the 250 mL group), but that was the only difference between groups. However, the authors did not measure any markers of fluid volume overload in the moms and babies. Interestingly, the authors note that in their previous clinical experience, moms who receive only 125 mL/hour of IV fluids seem thirsty and dehydrated. However not once in the entire article do the authors suggest that we could just let the thirsty moms drink!
In the second study with moms who were NPO, Eslamian et al. (2006) randomized 300 first-time moms to receive either 125 or 250 mL/hour. The first stage of labor and the total duration of labor were significantly shorter in the 250 mL group. Prolonged labor (greater than 15 hours) was more common in the 125 mL group, and the 125 mL group was more likely to have oxytocin augmentation for slow labor. There were no differences between groups with duration of pushing and C-section rate. The authors did not measure any markers of fluid overload in moms or babies.
Two more recent studies have looked at IV fluids in first-time moms (in spontaneous labor) who were allowed to drink as much fluids as they liked during labor. Coco et al. (2010) randomized 80 moms to receive IV fluids at 250 mL per hour or no IV fluids. Women in both groups were allowed to drink as much fluids as they desired (water, juice, sodas). There were no differences between groups with regard to total labor length, first stage of labor length, pushing, or oxytocin augmentation. No adverse effects were seen in either group. The authors did not mention anything about measuring markers of fluid volume overload in the moms or babies, so I contacted the primary author and asked– and no, no markers of fluid volume overload were measured. The researchers of this study concluded that women intuitively know how to drink enough fluids to self-regulate their fluid status during labor, making IV fluids unnecessary.
Finally, in 2012, Kavitha et al. randomized 293 moms into one of three groups: oral fluids (plain water and coconut water), IV fluids at 125 mL/hr, or IV fluids at 250 mL/hr. The women in the IV fluid groups were also allowed to have oral fluids. There were no differences between groups with length of labor (first stage, second stage, or total length), oxytocin augmentation, or any other complications. There were no differences in complication rates, and no cases of pulmonary edema (However, again, other signs and symptoms fluid volume overload were not measured). There was a decreased incidence of vomiting in the 250 mL group (6% vomiting in the 250 mL group versus 11% in the 125 mL group and 24% in the oral fluid group).
So after reading these studies, we can conclude that IV fluids offer only one benefit (decreased vomiting) to women who are allowed to drink during labor. But I still had a lot of questions after reading these studies. What is the effect of IV fluids on mom’s fluid status after delivery? Breastfeeding and engorgement? On baby fluid outcomes? None of the RCT’s covered these questions. So our next best evidence is to turn to some observational studies that looked at the relationship between IV fluids during labor and fluid volume overload in babies.
I found two observational studies that looked at the relationship between IV fluids during labor and newborn weight loss. I could not find any studies about IV hydration and postpartum edema (swelling) or breast edema/engorgement. Add that to the list of research studies I would like to conduct some day!
Chantry et al. (2010) followed 448 pregnant women through pregnancy and after birth to determine risk factors for excess weight loss in newborns (excess weight loss was defined as >10% of birth weight at 3 days old). Of the breastfed newborns, 16-19% experienced excess weight loss. The authors ran a regression (a powerful type of statistical technique) to determine the predictors of excess weight loss in these babies. The only two things that predicted excess weight loss in newborns were increased IV fluids given during labor and delayed milk production. If moms received more than 200 mL/hour of fluids, their babies were 3.2 times more likely to experience excess weight loss at 3 days compared to moms who had less than 100mL/hr of fluids. The infants whose mothers had a higher IV fluid rate—well, these babies also peed more during the first 4 hours of life. When you put 2 and 2 together, this means that the babies had too much fluid on board. They peed more after birth. Hence the excess weight loss at 3 days. The bad news?? Thirty percent of infants in this study (whose moms intended to exclusively breastfeed) were supplemented with formula. And in this study, supplementation with formula at 3 days was associated with decreased intent to breastfeed. Reason for supplementation? You guessed it. Excess weight loss, along with concerns about a delay in milk coming in.
So, this is the possible unintended consequence of receiving IV fluids during labor:
IV fluids (100-200+ mL/hour) during labor
Excess fluid loss in the newborn
Care provider concerned about “excess weight loss”
Mom feels like she is not making enough milk
Supplementation with formula
Decreased intent to breastfeed
In a smaller study, a different group of researchers also found that higher amounts of IV fluids during labor were associated with excess weight loss in newborns. The authors suggested that clinicians use the 24-hour weight—not the birth weight—as the baseline weight when following infant weight over time. Okay, this is just me talking, but wouldn’t a simpler, more evidence-based solution be to just let women drink during labor and avoid the whole IV fluid thing in the first place, seeing as that is the cause of the whole weight loss problem to begin with?
So, in summary, among women who have unrestricted access to oral fluids, IV hydration during labor offers only one advantage– it may reduce the incidence of nausea/vomiting. It does not have any other benefits. It does not shorten the length of labor. The risks are that IV hydration during labor may lead to an artificially high drop in the newborn’s weight, which can adversely affect breastfeeding. The risks related to post-partum edema and engorgement are unknown.
New addition to this post: I know that some of you would like to avoid this unnecessary intervention but may have difficulty convincing your healthcare provider to go along with you. So for a PDF, printable summary of this article on IV fluids written especially for your health care provider, click here.
If you would also like to print off the summary on eating and drinking during labor for your health care provider, click here.
Other printables are listed here.
So what do you think? Would you rather have IV fluids during labor or would you rather be allowed to drink? Any other thoughts that you have about IV fluids during labor?
- Chantry, C. J., L. A. Nommsen-Rivers, et al. (2011). “Excess weight loss in first-born breastfed newborns relates to maternal intrapartum fluid balance.” Pediatrics 127(1): e171-179.
- Coco, A., A. Derksen-Schrock, et al. (2010). “A randomized trial of increased intravenous hydration in labor when oral fluid is unrestricted.” Fam Med 42(1): 52-56.
- Eslamian, L., V. Marsoosi, et al. (2006). “Increased intravenous fluid intake and the course of labor in nulliparous women.” International journal of gynaecology and obstetrics 93(2): 102-105.
- Garite, T. J., J. Weeks, et al. (2000). “A randomized controlled trial of the effect of increased intravenous hydration on the course of labor in nulliparous women.” Am J Obstet Gynecol 183(6): 1544-1548.
- Kavitha, A., K. P. Chacko, et al. (2012). “A randomized controlled trial to study the effect of IV hydration on the duration of labor in nulliparous women.” Arch Gynecol Obstet 285(2): 343-346.
- Noel-Weiss, J., A. K. Woodend, et al. (2011). “An observational study of associations among maternal fluids during parturition, neonatal output, and breastfed newborn weight loss.” Int Breastfeed J 6:9.