Dr. Rebecca Dekker

Hi everyone. On today’s podcast, we’re going to talk about the impact of epidurals on the pushing phase of labor. Welcome to the Evidence Based Birth® Podcast. My name is Rebecca Dekker, and I’m a nurse with my PhD and the founder of Evidence Based Birth®. Join me each week as we work together to get evidence-based information into the hands of families and professionals around the world. 

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And now let’s talk all about the evidence on epidurals and the second stage of labor. This episode is replacing EBB 13, which was one of the first episodes of the EBB podcast back in the year 2018. If you prefer to learn by video, go visit our EBB YouTube channel, where you’ll find several new high-definition videos all about the evidence on epidurals. You can also find all the scientific references for today’s episode on our website at ebbirth.com/320. Morgan Cayama  Richardson, one of our EBB research fellows, prepared the research for today’s episode. So a big thank you to Morgan for compiling this research. 

A few weeks ago in episode 317, we gave you an overview of the newest evidence on epidurals and spinals for pain management during labor, including the effectiveness, benefits, risks, and alternatives. In today’s podcast, episode 320, we’re going to zoom in on the impact of epidurals on the second stage of labor. The second stage of labor begins when the cervix is fully dilated, includes the pushing phase, and ends when the baby is born. It’s important to talk about the length of the second stage of labor because longer second stages have been linked with poorer health outcomes, including a higher risk of maternal infection, a higher risk of having a severe tear of the perineum, a higher risk of postpartum hemorrhage or excessive bleeding, a higher risk of postpartum fever, and a higher risk of needing forceps, vacuum, or a Cesarean. So we have a lot of research showing that longer second stages are linked with higher risks of health problems. Are epidurals associated with longer second stages? And does research show there are more risks in the second stage if you have an epidural? Well, that’s what we’re going to cover in today’s episode. So are you ready? Let’s go. 

Impact of Epidurals on the Second Stage of Labor

So let’s start by talking about how physiologically an epidural or spinal could impact the pushing phase. Researchers have suggested that epidurals could potentially decrease your pushing efforts by reducing the effectiveness or strength of uterine contractions. This is because epidurals numb or decrease the feelings from nerves on your cervix and pelvic tissues. Now, normally, as the baby’s head descends and puts pressure on the cervix, there are nerve endings that send messages back to the pituitary gland in your brain. This stimulates your pituitary gland to produce more oxytocin, which is the hormone that strengthens contractions. So there’s this continual feedback loop where the baby’s head puts pressure on the cervix. The pituitary gland releases more oxytocin. The uterine contractions get stronger and more expulsive to push the baby down and out. This puts more pressure on the cervix, so more oxytocin is released, and so on. This is called the utero-pituitary reflex and was first studied by J.K.W. Ferguson, a scientist, who was looking at sheep giving birth in the 1940s. Some people call this the Ferguson reflex, but I’ve been thinking recently that here at EBB, we should try to avoid reinforcing the trend of naming birth reflexes after men. So I’ll be calling it the utero-pituitary reflex, or in the context of this podcast, just the reflex that we’re discussing. 

So what does this have to do with epidurals? Well, it’s thought that the epidural can interrupt this utero-pituitary reflex. And possibly epidurals might also be relaxing the muscles of the pelvic floor, which could affect the baby as it’s rotating and coming out through the pelvis. If the theory is correct that epidurals weaken your contractions, then it’s likely that a dose-response relationship exists between the concentration of the local anesthetic in the epidural and the effects on the second stage of labor. In other words, the higher the dose of medication in the epidural, the weaker your contractions because of that interference with the normal reflex. This is why sometimes with an epidural or spinal, you will often see synthetic oxytocin, known as Pitocin or Syntocinon, given through an IV, to try and counteract this lower production of your own natural oxytocin. A synthetic oxytocin and your own endogenous oxytocin are a little bit different. They’re chemically identical, but the delivery is different because your own natural oxytocin is released from your brain where it also has some pain-relieving impacts as well as other impacts. The oxytocin that is made synthetically and given through your IV cannot cross the blood-brain barrier, so it does not have those natural pain-relieving effects. I just say this to mention that care providers do try to manage this impact on the reflex by giving Pitocin IV if your contractions don’t seem to be strong enough when you have an epidural. If you have a lower dose epidural with lower doses of medications, there might be less interference with the reflex and you might not see as much of an impact of the epidural on the second stage.  We talk more about this in our overview video in episode 317 and also in some of our pocket guides here at EBB about comfort measures and about interventions, but having a lower dose epidural is something you can ask for. So that’s what researchers propose is happening physiologically in the body. 

Evidence on Epidurals on the Second Stage of Labor

But what does the evidence show? Well, actually, we have many, many studies over many decades showing that epidurals are linked to a longer second stage of labor. This has been seen in large observational studies where they’re looking at large cohorts of people, as well as in randomized controlled trials. There have only been a few newer studies on this topic. This is something that’s been studied for many years. And so because this association has been shown over and over, you don’t see as much new research on this anymore. But I will talk about a few newer studies. There was a new meta-analysis published in 2020 by Pergialiotis with 13 observational studies that were combined representing more than 337,000 births from around the world. They found the participants who had an epidural during labor had five times the odds of experiencing a prolonged second stage of labor. The definition for what was a prolonged second stage of labor was different in the different studies. However, most of the studies defined it as more than three hours of pushing for someone who has an epidural and is giving birth for the first time and more than two hours of pushing for someone with an epidural who has given birth previously. They also found that a prolonged second stage led to five times the odds of having a vacuum or forceps-assisted birth. 

A smaller study came out in 2023. This was published by He and Wang and was conducted in China. In this study, the researchers reviewed patient medical records to divide everyone into two groups, one group where everyone had an epidural and the other group that did not have an epidural during labor. They were only looking at low-risk women who were pregnant with a single baby, whose labor began spontaneously so they were not induced. The baby was in the head-down position, so no breech babies, and the parents were intending a vaginal birth. This was a slightly smaller study with only about 246 people in the epidural group and 226 in the non-epidural group. They found that those with an epidural had a longer second stage of labor, 79 minutes on average, compared to the non-epidural group, 57 minutes. They also found no differences between the groups in Cesarean rates. There’s also a Cochrane review published by Anim‐Somuah et al. In 2018 that looked at 40 randomized controlled trials with more than 11,000 participants. So in these studies, people were randomly assigned, like flipping a coin, to have an epidural during labor or not. They found that the second stage of labor was longer by about 15 minutes for those with an epidural, but just like the study I discussed, they found no increased risk for Cesarean if you had an epidural. I still occasionally get questions about a study that came out in 2017 published by Shen et al., and people tend to interpret that study as meaning that epidurals do not lengthen the second stage of labor. So in the past, we’ve had a lot of people reach out with questions about that study. 

What does this mean? A lot of this came from, if you Google the topic, you might find a Huffington Post article with a headline that said, epidurals don’t necessarily slow labor, study finds. So what was this study that they were talking about in the media? Well, the study took place in China in the year 2015 and was published in 2017. The participants in the study were first-time mothers giving birth at term to a single baby, and all of the mothers went into labor spontaneously, and they all requested to have epidurals. So everybody in this study had an epidural. There was not a control group without an epidural. However, the epidurals were all low dose epidurals. Remember, I talked about that earlier as being an option where you can still have effective pain management, but with fewer side effects from the medications. At the start of the pushing phase of labor, everyone in the study had already been receiving the epidural through the first part of labor. And then at the second stage, at the start of the second stage, this is where the randomized trial began. 178 mothers were randomly assigned to receive saline placebo through their epidural during the second stage, and 171 mothers were randomly assigned to continue receiving the low-dose epidural solution with epidural medications. Now all of the patients and the care providers were blinded, so they didn’t know what type of solution was being given through the epidural during the pushing phase. At the end, when they revealed the groups and analyzed the data, they found that the length of the pushing phase was similar in both groups. It was about, on average, 51 to 52 minutes of pushing. 

Also, rates of vaginal birth were similar between the two groups, about 97% to 99%. It’s also interesting to note that the pain scores were similar between the groups. What this means is that both groups were still being impacted by the epidural medications they’d received during the first stage of labor. And this is where it can be so enlightening to look at the actual methods section of a study instead of just reading a headline. So what you can see from reading the full-length study is that all of the women in this study received ropivacaine as the anesthetic through the epidural throughout the first stage. This is a long-acting drug that lasts about, on average, four hours in your body after they stop giving it to you. So even though they had turned the epidural off for half of the people in the study, the medications were still in the system of everyone. 

So this study was not comparing epidural versus no epidural. It was looking at the effects of turning off the epidural when it has this specific medication at the start of the second stage. And basically, they found that because this medication remained in the participant’s bodies, turning off the epidural at the start of the second stage probably wouldn’t have any impact on the length of the second stage. So this is a great example of a time to be wary of news headlines that say things like new study proves. It’s important to look at the overall body of evidence and look at the actual studies themselves. And think, what has all the research shown up until this point? If you knew we had decades of research showing that epidurals lengthen the second stage of labor, that might make you think twice about a news headline that says epidurals don’t impact the second stage of labor. If you can, you might want to try and find the study for yourself and look at it or ask somebody else to look at it with you, like a trusted healthcare provider. Here at EBB, we love looking at the methods of how people carry out the study, including the limitations of the study, the drawbacks of the study, and where we cannot draw conclusions that are not supported by the data. A lot of people were tricked by these news headlines. They thought that this meant epidurals don’t lengthen the second stage. And that’s not even what this study was examining. So it can’t be what they found. 

What are the Professional Guidelines?

I want to talk a little bit about the professional guidelines, and we’re going to look at two associations and see what they say about the prolonged second stage of labor. In early 2024, the American Congress of Obstetricians and Gynecologists, also known as ACOG, released recommendations about managing labor and managing labor arrest. They define, quote, prolonged second stage of labor, end quote, as more than three hours of pushing in someone who’s giving birth for the first time or more than two hours of pushing in someone who’s given birth before. Now, labor arrest is a diagnosis as well. Not my favorite terminology, but it is the one that ACOG uses. Some people might think of it as when labor just completely stops progressing. And so when they come to labor arrest, ACOG recommends an individualized approach rather than a one-size-fits-all definition. They say that an individual diagnosis of labor arrest should take into consideration several factors, including the patient’s preferences for labor and birth, their labor progress, and factors in the birth setting that impact the likelihood of being able to give birth vaginally, including the risks and benefits of available interventions. If arrest in the second stage is diagnosed, ACOG recommends that the care provider attending the birth consider using forceps or vacuum in a vaginal birth before resorting to a Cesarean. I want to give you a quick side note and let you know that in EBB 244, we talk about the evidence on something called assisted vaginal delivery, which is when forceps or vacuum device are used to help with the vaginal birth of a baby. So go to EBB 244 to learn more about that. 

It’s important to note that ACOG also currently recommends that patients begin pushing when the cervix is fully dilated rather than delayed pushing, which is also known as laboring down. This is a controversial topic in the birth world. Some care providers still prefer delayed pushing because they feel like it lessens exhaustion or has other benefits, and I’ll talk a little bit about those benefits in a minute. But currently, ACOG does not recommend delaying pushing or laboring down if you have an epidural. The National Institute for Health and Care Excellence, or NICE in the United Kingdom, provides clinical practice guidelines for healthcare workers in the UK. They updated their recommendations for intrapartum care in 2023, and they divide the second stage into two phases, passive and the active phase of the second stage. The passive phase begins when the cervix is fully dilated, but before any pushing has started. You may have seen this before or known of someone who was fully dilated, but did not begin pushing right away for a variety of reasons. That would be the passive phase. For me, it happened when I was fully dilated, but the staff were all in reports. They told me I could not push for 30 minutes, which happened to me 15 years ago. And I’m not saying that that happens all the time now, but it was an interesting experience to be told you’re not allowed to push. And I definitely felt the urge to push. So I kind of had passive labor or laboring down on accident. The passive phase of the second stage may take up to two hours where someone who has an epidural, they’re giving birth for the first time, and they may labor down for several hours after full dilation before they begin pushing, while someone who has given birth before might wait up to one hour before pushing if they have an epidural and they’re fully dilated. Again, this is called delayed pushing or laboring down. 

Interestingly, in contrast to ACOG, NICE recommends laboring down based on evidence that it might lower the risk of unplanned Cesarean, it lowers the risk of needing a vacuum or forceps in those who have given birth before, and it shortens the length of the active phase. The active phase begins when the baby is visible or when the cervix is fully dilated and pushing has started. NICE goes on to identify abnormals and states, that a delay in the second stage of labor is defined as more than three hours of pushing in the active phase of the second stage if you are giving birth for the first time, and more than two hours of actively pushing if you have given birth before. If you wanna learn more about the evidence on laboring down, you might wanna check out the Cochrane review on this subject. The Cochrane article on delayed pushing gives a nice review and summary of the evidence that’s been published so far, but says that the evidence on laboring down is still insufficient and inconclusive. Which is why I think we’re seeing different organizations say different things. In terms of the length of the second stage and the diagnosis of labor arrest, you can learn more about longer labors in our signature article on “Failure to Progress.” And we also have a companion article about the prolonged second stage of labor. So you can find both of those at ebbirth.com/failuretoprogress. That’s all one word, Failure to Progress.

I also wanted to point out that birthing positions can also impact the length of the second stage if you have an epidural. You can find more about birthing positions and pushing, whether or not you have an epidural, in the EBB signature article called “Birthing Positions,” available at ebbirth.com/birthingpositions.

And we also have podcast episodes for each of those, so I’ll link to those in the show notes. So to wrap it all up in today’s episode, we started by talking about how physiologically an epidural or spinal given for pain management and labor could impact the pushing phase by lessening the utero-pituitary reflex. And then we talked about how many studies have shown epidurals are linked to a longer second stage of labor, both in observational studies and randomized trials. There might be a dose-response relationship, meaning that the higher the dose of medication, the stronger the impact on a longer second stage. So low-dose epidurals might be beneficial. However, epidurals do not seem to necessarily increase the risk of Cesarean in the second stage. And if you go back to EBB 317, we talk a lot about the benefits and the overall risks of epidurals and how epidurals are the most effective form of medication pain management for labor. Having a doula, nurse, or midwife who is skilled in helping parents with epidurals find the right birthing positions and also having a provider who understands that epidurals might lengthen the second stage. So you need to have more patience in that scenario. These are both important factors. That’s why I think information can be so powerful. 

So epidurals lengthen the second stage, but if you have the right support, this should not necessarily lead, for example, to a higher risk of needing surgery. And I think it’s interesting that the whole concept of laboring down is still so controversial around the world. Maybe at some point we need to do a deep dive on the evidence on laboring down. But until then, make sure you’ve checked out our episodes on birthing positions and failure to progress. And you can also check out our other episodes and YouTube videos on pain management during labor, because we have a whole series of videos about non-medication methods that you can also put in your toolkit to more effectively manage pain and labor, whether or not you have an epidural. I hope you found this information helpful, and we will be back next week with a really empowering home birth story with a first-time mom and EBB childbirth class graduate. So keep your eyes open for next week’s episode. Thanks, everyone, and I’ll see you next week. Bye. 

Today’s podcast episode was brought to you by the online workshops for birth professionals taught by evidence-based birth instructors. We have an amazing group of EBB instructors from around the world who can provide you with live, interactive, continuing education workshops that are fully online. We designed Savvy Birth Pro workshops to help birth professionals who are feeling stressed by the limitations of the health care system. Our instructors also teach the popular Comfort Measures for Birth Professionals and Labor and Delivery Nurses Workshop. If you are a nurse or birth professional who wants instruction in massage, upright birthing positions, acupressure for pain relief, and more, you will love the Comfort Measures Workshop. Visit ebbirth.com/events to find a list of upcoming online workshops.