Epidurals: Do They or Don't They Increase Cesareans?

By Henci Goer

In October, Author Henci Goer wrote an article for Science & Sensibility, Epidural Anesthesia: To Delay or Not To Delay – That is the Question – examining the impact of the timing of an epidural on labor and birth.  Today Henci looks at some new research, Epidural analgesia in labour and risk of caesarean delivery which seeks to determine whether receiving an epidural at all impacts the likelihood of a cesarean delivery.  Lamaze International has a great infographic on epidurals that you also may find very helpful. – Sharon Muza, Community Manager, Science & Sensibility.

© J. Wasikowski, provided by Birthtastic
© J. Wasikowski, provided by Birthtastic

Let’s start with a bit of background for those of you who didn’t personally live through the early controversy over whether epidurals increased the cesarean rate. As epidurals began to achieve popularity in the late 1970s and 1980s, one researcher sounded the alarm when he and his group published a study of 714 first-time mothers showing that even after excluding women with big babies and women whose labor pattern was abnormal prior to having an epidural, epidurals remained a potent factor in cesarean rates for delayed progress (Thorp 1989). Everyone pooh-poohed his finding on grounds that observational studies can’t truly determine whether epidurals lead to more cesareans or women experiencing more prolonged, painful labors, and therefore at higher risk for cesarean, were more likely to want epidurals. The “chicken versus egg” question, they argued, couldn’t be resolved without a randomized controlled trial (RCT), and it wasn’t likely that women would agree to be assigned by chance to have an epidural or not. In point of fact, that same year saw publication of a small Danish RCT (107 women, 104 of them first-time mothers) (Philipsen 1989). It reported that having an epidural nearly tripled the cesarean rate (16% vs. 6%) for “cephalopelvic disproportion” despite no clinical evidence of CPD being a requirement for inclusion. The investigators ignored this, however, concluding only that instrumental vaginal delivery rates were similar, and epidurals provided better pain relief. In any case, the anesthetic dose was much higher than was already becoming the norm, so it could be reasonably argued that the trial’s findings wouldn’t apply to modern-day practice.

Thorp, meanwhile, took up the RCT challenge. He and his colleagues carried out an epidural versus no epidural trial in 93 first-time mothers and found that epidurals did, in fact, lead to cesareans (25% vs. 2%), not vice versa (Thorp 1993). That bit of unwelcome news precipitated a stampede to perform more RCTs, and when enough of those had accumulated, to a series of systematic reviews pooling their data (meta-analysis), of which the Cochrane review, Anim-Somuah et al. (2011), is the latest. These reached the more comfortable conclusion that epidurals didn’t increase likelihood of cesarean, and pro-epiduralists breathed a collective sigh of relief and went back, if they had ever stopped, to unreservedly recommending epidurals. (This rather sweeps under the rug the other problems epidurals can cause, but that’s a topic for another day.)

Weaknesses of the “Epidural” vs. “No Epidural” Trials

By User: Ravedave (Own work)
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The finding that epidurals don’t increase cesareans is puzzling because they increase likelihood of factors associated with them (Anim-Somuah 2011). For one thing, they increase use of oxytocin to augment labor, which implies they slow labor. For another, more women run fevers, and it stands to reason that a woman progressing slowly who starts running a fever is a likely candidate for cesarean. For a third, the difference in fetal malposition (occiput posterior) rates at delivery comes close to achieving statistical significance, meaning the difference is unlikely to be due to chance. Persistent OP is strongly associated with cesarean delivery (Cheng 2006; Fitzpatrick 2001; Phipps 2014; Ponkey 2003; Senecal 2005; Sizer 2000). Epidurals even increase cesareans for fetal distress by 40%, although the absolute difference didn’t amount to much (1 more per 100 women). Could a difference exist and meta-analysis of RCTs fail to detect it?

A string of well-conducted observational studies over the years have suggested that they could (Eriksen 2011; Kjaergaard 2008; Lieberman 1996; Nguyen 2010), the most recent of which is a very large, very convincing study published last fall (Bannister-Tyrrell 2014). Its authors point out, as have others before them, the weaknesses of the RCTs, weaknesses serious enough to nullify their results or make them inapplicable to typical community practice (external validity).

To begin with, in most trials, substantial percentages of women allocated to the non-epidural group ended up having epidurals, and some women allocated to the epidural group ended up not having one. Since RCTs analyze results according to group assignment (to do otherwise would negate the point of random assignment, which is to avoid bias), not what actually happened, this diminishes differences between groups. In addition, trials were mostly confined to women with no medical or obstetric complications who were treated according to strict protocols for labor management and indications for cesarean delivery. Neither is the case in most hospitals. To these I would add that many trials lumped together first-time mothers and women with prior births when reporting outcomes. First-time mothers are much more susceptible to factors that impede progress, so including women with prior vaginal births can make it appear that epidurals are less problematic for first-time mothers than they really are. In addition, three of the trials were carried out in a hospital where participants were mostly attended by midwives, and cesarean rates were much lower than is common for women attended by obstetricians.

All of this means that any null results in meta-analyses of the trials can be taken with a grain of salt, any findings of significant differences probably represent a minimal value, and first-time moms may be harder hit than appears. To cite one example, Anim-Somuah (2011) reported that 5 more women per 100 having epidurals had a malpositioned baby at delivery (18% vs. 13%) in the 4 trials reporting this outcome, a difference, as I said, that just missed achieving statistical significance. But when I confined results to the two trials in first-time mothers alone in which 10% or fewer of the women in the “no-epidural” group had an epidural, the gap widened to 9 more per 100 (11% vs. 2%).

Summary of the Bannister-Tyrrell (2014) Analysis

Bannister-Tyrrell and colleagues (2014) drew their population from a database of 210,700 Australian women with no prior cesareans who were laboring at term with a singleton, head-down baby. A strength of the database was that, unlike most, it distinguished epidurals for labor from epidurals for delivery. Using a long list of factors, investigators constructed a propensity score for how likely a woman was to have an epidural, matched women according to their score, and compared results according to whether women with the same score had or didn’t have an epidural. Matched controls were found for 52,600 women who had an epidural and were found across the full range of propensity scores. Women having epidurals were 2.5 times more likely to have a cesarean (20% vs. 8%), or put another way, 12 more women per 100 having epidurals had a cesarean (absolute excess), which amounts to 1 additional cesarean for every 8.5 women having an epidural (number needed to harm). Among first-time mothers, women having epidurals were 2.4 times more likely to have a cesarean. Study authors didn’t provide cesarean rates for this subgroup, but the raw cesarean rates overall were 18% in first-time mothers versus 2% in women with prior births, so the effect on this more vulnerable population could be dire.

But there’s still more. Investigators further adjusted for confounding factors not captured in their database. These included differences in health-care settings (same state but not same city), care provider (women without epidurals are more likely to be attended by midwives), and for confounding interventions more likely with epidurals (continuous fetal monitoring). Relative risk of cesarean with an epidural remained at 2.5. Investigators then adjusted for the association between occiput posterior baby and cesarean by setting estimates of the risk ratio to exceed the strongest associations reported in the literature, and they assumed that the prevalence of severe labor pain was 3 to 4 times higher in women having epidurals. Factoring these into their statistical analysis reduced the risk ratio, but women having epidurals still were 50% more likely to have a cesarean. This means that with a baseline cesarean rate of 8% in women without an epidural, 12% of women with an epidural will have one or 4 more women per 100 or 1 more cesarean for every 25 women.

The Take-Home

At the very least we cannot assure women with confidence that epidurals don’t increase the likelihood of cesarean. For this reason and because of their numerous other drawbacks and considering that comfort measures and other strategies have been shown to be both effective for most women and free of adverse effects (Declercq 2006; Jones 2012), women may want to make epidurals Plan B rather than Plan A. That being said, whatever their choice, women can minimize their chance of cesarean—with or without an epidural—by choosing a midwife or doctor whose policies and practices promote spontaneous vaginal birthhttp://www.lamaze.org/HealthyBirthPractices.


Anim-Somuah, M., Smyth, R. M., & Jones, L. (2011). Epidural versus non-epidural or no analgesia in labour. Cochrane Database Syst Rev(12), CD000331. doi: 10.1002/14651858.CD000331.pub3 http://www.ncbi.nlm.nih.gov/pubmed/22161362

Bannister-Tyrrell, M., Ford, J. B., Morris, J. M., & Roberts, C. L. (2014). Epidural analgesia in labour and risk of caesarean delivery. Paediatr Perinat Epidemiol, 28(5), 400-411.http://www.ncbi.nlm.nih.gov/pubmed/25040829

Cheng, Y. W., Shaffer, B. L., & Caughey, A. B. (2006). Associated factors and outcomes of persistent occiput posterior position: A retrospective cohort study from 1976 to 2001. J Matern Fetal Neonatal Med, 19(9), 563-568. http://www.ncbi.nlm.nih.gov/pubmed/16966125?dopt=Citation

Declercq, E., Sakala, C., Corry, M. P., & Applebaum, S. (2006). Listening to Mothers II: Report of the Second National U.S. Survey of Women’s Childbearing Experiences. New York: Childbirth Connection. http://childbirthconnection.org/pdfs/LTMII_report.pdf

Eriksen, L. M., Nohr, E. A., & Kjaergaard, H. (2011). Mode of delivery after epidural analgesia in a cohort of low-risk nulliparas. Birth, 38(4), 317-326. http://www.ncbi.nlm.nih.gov/pubmed/22112332

Fitzpatrick, M., McQuillan, K., & O’Herlihy, C. (2001). Influence of persistent occiput posterior position on delivery outcome. Obstet Gynecol, 98(6), 1027-1031. http://www.ncbi.nlm.nih.gov/pubmed/11755548?dopt=Citation

Jones, L., Othman, M., Dowswell, T., Alfirevic, Z., Gates, S., Newburn, M., . . . Neilson, J. P. (2012). Pain management for women in labour: an overview of systematic reviews. Cochrane Database Syst Rev, 3, CD009234. http://www.ncbi.nlm.nih.gov/pubmed/22419342

Kjaergaard, H., Olsen, J., Ottesen, B., Nyberg, P., & Dykes, A. K. (2008). Obstetric risk indicators for labour dystocia in nulliparous women: a multi-centre cohort study. BMC Pregnancy Childbirth, 8, 45.http://www.ncbi.nlm.nih.gov/pubmed/18837972?dopt=Citation

Lieberman, E., Lang, J. M., Cohen, A., D’Agostino, R., Jr., Datta, S., & Frigoletto, F. D., Jr. (1996). Association of epidural analgesia with cesarean delivery in nulliparas. Obstet Gynecol, 88(6), 993-1000. http://www.ncbi.nlm.nih.gov/pubmed/8942841

Nguyen, U. S., Rothman, K. J., Demissie, S., Jackson, D. J., Lang, J. M., & Ecker, J. L. (2010). Epidural analgesia and risks of cesarean and operative vaginal deliveries in nulliparous and multiparous women. Matern Child Health J, 14(5), 705-712.http://www.ncbi.nlm.nih.gov/pubmed/19760498?dopt=Citation

Philipsen, T., & Jensen, N. H. (1989). Epidural block or parenteral pethidine as analgesic in labour; a randomized study concerning progress in labour and instrumental deliveries. Eur J Obstet Gynecol Reprod Biol, 30(1), 27-33. http://www.ncbi.nlm.nih.gov/pubmed/2924990

Phipps, H., Hyett, J. A., Graham, K., Carseldine, W. J., Tooher, J., & de Vries, B. (2014). Is there an association between sonographically determined occipito-transverse position in the second stage of labor and operative delivery? Acta Obstet Gynecol Scand, 93(10), 1018-1024.http://www.ncbi.nlm.nih.gov/pubmed/25060716

Ponkey, S. E., Cohen, A. P., Heffner, L. J., & Lieberman, E. (2003). Persistent fetal occiput posterior position: obstetric outcomes. Obstet Gynecol, 101(5 Pt 1), 915-920.http://www.ncbi.nlm.nih.gov/pubmed/12738150?dopt=Citation

Senecal, J., Xiong, X., Fraser, W. D., & Pushing Early Or Pushing Late with Epidural study, group. (2005). Effect of fetal position on second-stage duration and labor outcome. Obstet Gynecol, 105(4), 763-772. http://www.ncbi.nlm.nih.gov/pubmed/15802403

Sizer, A. R., & Nirmal, D. M. (2000). Occipitoposterior position: associated factors and obstetric outcome in nulliparas. Obstet Gynecol, 96(5 Pt 1), 749-752.http://www.ncbi.nlm.nih.gov/pubmed/11042312?dopt=Citation

Thorp, J. A., Hu, D. H., Albin, R. M., McNitt, J., Meyer, B. A., Cohen, G. R., & Yeast, J. D. (1993). The effect of intrapartum epidural analgesia on nulliparous labor: a randomized, controlled, prospective trial. Am J Obstet Gynecol, 169(4), 851-858. http://www.ncbi.nlm.nih.gov/pubmed/8238138?dopt=Citation

Thorp, J. A., Parisi, V. M., Boylan, P. C., & Johnston, D. A. (1989). The effect of continuous epidural analgesia on cesarean section for dystocia in nulliparous women. Am J Obstet Gynecol, 161(3), 670-675. http://www.ncbi.nlm.nih.gov/pubmed/2782350

About Henci Goer

Henci Goer
Henci Goer

Henci Goer, award-winning medical writer and internationally known speaker, is the author of The Thinking Woman’s Guide to a Better Birthand Optimal Care in Childbirth: The Case for a Physiologic Approach She is the winner of the American College of Nurse-Midwives “Best Book of the Year” award. An independent scholar, she is an acknowledged expert on evidence-based maternity care.  


@Lisa You have your read on th

January 27, 2015 07:00 AM by Henci Goer, BA
@Lisa You have your read on the research, and I have mine. I think we'll just have to agree to disagree on this one. My sources are there for any viewers who want to read the studies and decide what they think.

This is how I read this. Am I

January 27, 2015 07:00 AM by Lisa
This is how I read this. Am I missing something? "When epidurals first came out, they were associated with a higher cesarean rate. But causation was questionable because women were more likely to have an epidural if they had the type of difficult labor that was prone to a c-section. There was therefore a call to do randomized, controlled studies. The first ones done, which were nearly 25 years ago and thus studied outdated, outmoded forms of epidural anesthesia, showed that epidurals did increase the chance of a c-section. Then more recent studies have shown that actually, at least with current epidural analgesic, they do not. But we can probably discount the more recent studies, because they are littered with the very problems we already knew would make any randomized, controlled trial impossible, factors that would undoubtedly have plagued the earlier studies as well but were not mentioned in that discussion. In summary, it's true that there is no good evidence that current epidural anesthesia increases the chance of a c-section, but for some reason I am going to continue to hint that it just might, at least a tiny bit, somehow."

With the importance of fulfill

January 28, 2015 07:00 AM by Angela Bristow
With the importance of fulfilling birth experiences and healthy mothers and babies, it seems that research that shows even a possible link to a very serious and dangerous surgery like cesarean, let alone other risks to mother and baby, should be sharply reduced in practice. This is perhaps more true when research also shows that non-drug pain relief measures, such as movement, position changes, hydro/aromatherapy, etc., can be just as relieving to women when combined as an epidural. They are also much safer overall even when not considering the potential link to increased cesarean rates.

During the time that I was wor

January 30, 2015 07:00 AM by Carol Van Der Woude, RN, BSN
During the time that I was working in a labor/delivery unit in a community hospital--up until 7/2014 I saw significant variation in the level of anesthesia that a woman experienced with an epidural. Some women had no feeling, no use of their legs at all. Sometimes it was the type of drug used, sometimes it was repeated doses of medication for breakthrough pain. When my daughter gave birth she did not plan to have an epidural but needed the pain relief when she was in good active labor. She was fortunate to receive an epidural that allowed her complete movement of her legs and the ability to move side to side in bed. The doctor was patient and she delivered vaginally. It is hard to control for the variability in the type of drug (agent) used for the epidural, the point that it is given in labor, and the degree of movement that the laboring woman can achieve.

"For one thing, [epidurals] in

January 30, 2015 07:00 AM by Michelle
"For one thing, [epidurals] increase use of oxytocin to augment labor, which implies they slow labor." Actually-- this is just my conjecture, but-- IMO I think many OBs and some hospital MWs see little downside to augmenting with pitocin ("why not speed things up?/help things along?") And it's certainly easier to convince a woman with an epidural, who cannot feel the (usually significantly) increased pain, that she needs a little pitocin (or a lot). That is-- if convincing is done at all, rather than simply informing (and occasionally, not even really informing). I think one of the biggest issues with epidurals is not epidurals themselves-- which can be really helpful at times-- but that they are part of the sort of Standard Package of Birth Interventions, from which it is difficult to isolate exactly what alchemy is (IMO clearly) leading to increased C/S and other complications without improved outcomes, particularly in the last 30 years. Is it pitocin, is it the epidural itself, CFM, even just the subconscious attitude of nurses and doctors attending a patient who has an epidural placed vs. one who does not...?? Some combination? This is one of those nearly-impossible questions to answer.

Well, letƒ??s examine one

January 30, 2015 07:00 AM by Do epidurals increase the odds of needing a Cesarean birth? - Vinings Childbirth Class with Expectin
Well, letâ??s examine one of the most common substances to enter the body during childbirth: epidural anesthesia. If youâ??re looking for even more specific research on the topic (which my post will not cover), check out Science & Sensibilityâ??s newest post. [?]

I am also concerned with the l

January 30, 2015 07:00 AM by Rosanne Gephart
I am also concerned with the long term effects of the prolonged second stage as a result of an epidural. I am seeing more perineal weakness and organ pro laps in women who have only had one or two babies!

Lisa, yes, you've definitely "

January 30, 2015 07:00 AM by Mamasaurus
Lisa, yes, you've definitely "missed something" and, sadly, it's all right there. Before trying to insult the research you've failed to decipher it would be in your best interest to dedicate more time to understanding what is laid out before us. I do sincerely hope the reading audience chooses to ignore the rather rude ramblings of someone who defines herself as merely married to a medical residency student; the author of this piece has impeccable credentials and has already included the sources that explain why Lisa's comment is incorrect and irrelevant.

I've definitely seen women hav

February 26, 2015 07:00 AM by Knitted in the Womb
I've definitely seen women have cesareans after they get epidurals then develop a fever several hours later. I think epidurals can be a useful tool...but I absolutely believe that they can lead to cesarean.

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