Do epidurals during planned VBACs mask uterine rupture pain or delay its diagnosis?
Note: I originally wrote this article in 2012, but did a complete update in 2020 incorporating the latest research on planned VBACs, epidurals, and uterine rupture.
You may have heard that epidurals interfere with the diagnosis of uterine rupture. Some providers believe this to be true and as a result discourage – or even “prohibit” – epidurals in people laboring after a cesarean fearing that it will mask the symptoms of uterine rupture (namely abdominal pain) and delay diagnosis resulting in a poor outcome. The anesthesia department at one rural California hospital says that they will not administer epidurals to planned VBACs due to the concern. But is this belief and policy rooted in the evidence?
Uterine rupture symptoms
Before we can talk about epidurals masking abdominal pain from uterine rupture, we need to get clear on how uterine ruptures are typically diagnosed.
So many people believe that abdominal pain is the primary and most reliable sign that a uterine rupture is impending or occurring, but there are actually many other symptoms that occur at a greater rate than abdominal pain and thus are more reliable indicators.
Per a review of the research on uterine rupture symptoms, the most common uterine rupture symptom is prolonged deceleration in fetal heart rate (bradycardia), occurring in 80% of 114 uterine ruptures across 4 studies. (Nahum, 2018)
The second most prevalent uterine rupture symptom is an abnormal pattern in fetal heart rate occurring in 54% of 187 uterine ruptures across 8 studies.
The next set of symptoms are uterine tachysystole or hyper-stimulation (40%), vaginal bleeding (37%), and shock (33%).
The sixth uterine rupture symptom – SIXTH – is abdominal pain. Among 118 uterine ruptures, across 9 studies, only 26% reported abdominal pain.
The least likely occurring symptom was loss of intrauterine pressure or cessation of contractions, which occurred in only 4% of uterine ruptures.
This is why the routine use of intrauterine pressure catheters (IUPCs) in planned VBACs is not evidence based. With only 4% of uterine ruptures reporting a loss of intrauterine pressure, the symptom is not strong enough to justify the invasive nature of IUPCs which is often coupled with limited, if no, mobility during labor.
Since that review was created, a couple more studies have been published on uterine rupture symptoms, specifically abdominal pain.
In 2009, the largest study of uterine rupture without a prior cesarean was published. (Zwart, 2009) They reported 210 uterine ruptures, 183 of which occurred after one or more prior cesarean sections with one person just having a prior myomectomy.
69% of those uterine ruptures resulted in abdominal pain in a population where 40% received an epidural. (In other articles, I use the data in Zwart to dispel two VBAC myths: that the risk of uterine rupture doesn’t change much after a cesarean and the risk of uterine rupture after a cesarean is similar to a first time parent who is induced).
Unfortunately, Zwart did not break out the epidural rate, or the rate of uterine rupture-related abdominal pain, by the presence or absence of prior uterine surgery, so we can’t say whether scarred or unscarred uterine ruptures differ in reported pain.
Three years later, a study of 159 uterine ruptures with and without prior uterine surgery out of the United Kingdom reported that 76% of uterine ruptures were accompanied by fetal heart rate abnormalities in comparison to 49% reporting abdominal pain. (Fitzpatrick, 2012)
I also want to share additional symptoms that I have collected from a variety of sources because sometimes multiple signs will accompany a uterine rupture and understanding all the ways uterine rupture can present can facilitate a rapid diagnosis:
- Fetal head moves back up birth canal/ loss of station
- Bulge in the abdomen or under the pubic bone (where the fetus may be coming through the opening in the uterus)
- Uterus becomes soft
- Shoulder pain
Planned VBACs, epidurals, and uterine rupture-related abdominal pain
With that knowledge under our belt, what does the available evidence say about the intersection of planned VBACs, epidurals, and uterine rupture-related abdominal pain? Do epidurals in those studies result in a delay of uterine rupture diagnosis?
In 1990, a review of 14 VBAC studies including almost 11,000 labors after cesarean was published. (Johnson, 1990) It examined specifically the incidence of uterine rupture-related abdominal pain reported among those who had an epidural and those who did not.
This study found that people laboring after a cesarean with epidurals who experienced a uterine rupture were more likely to report abdominal pain than those without epidurals, 36% versus 17%. When looking at the total population, only 22% had abdominal pain signal their uterine rupture.
I couldn’t find any mention of epidurals masking uterine rupture pain in the Guise 2010 Evidence Report, on which the 2010 National Institutes of Health VBAC Conference was based, but found that the Johnson study was excluded from their report because “No full-text paper, opinion or letter with no data.” Interesting.
Then fast forward to a single-center 2018 study out of Israel of over 7,100 planned VBACs, 57% (4081) of which had an epidural. (Grisaru-Granovsky, 2018) It did not report any difference in uterine rupture outcomes or note any delay in uterine rupture diagnosis.
Notably, this is one of the few modern studies I have read that combines uterine dehiscence with uterine rupture.
Uterine dehiscence is a typically asymptomatic and benign separation of the inner layer of the uterus while the outer layer of the uterus, the serosa, stays intact. Typically uterine dehiscences are not even diagnosed unless someone has a cesarean. Those in vaginal births are rarely noted. In comparison, a uterine rupture is a complete opening through the uterine wall.
Typically these two distinct events are reported separately, as their symptoms and outcomes are quite different. This is why it’s always important to read the full text of a study and not just the abstract.
In the abstract, Grisaru-Granovsky states that the rate of uterine rupture was 0.4% among those who had an epidural and 0.29% among those that did not.
It’s only upon reading the full text do you see that they combine uterine dehiscence with uterine rupture. The rate of complete uterine rupture was 0.3% among those with an epidural and 0.2% among those without. These rates were not significantly different.
These similar rates were rather surprising given that those with epidurals were much more likely to receive oxytocin during labor (25% vs 9%). Oxytocin administration was typically in the form of augmentation as induction was quite uncommon (6% vs 3%).
I wonder if this very low induction rate, or perhaps their specific induction or augmentation protocols, neither of which were shared in the study, were responsible for the low rate of overall uterine rupture reported by this study.
We know that induction during planned VBACs when a medical indication presents is evidence based, but it’s important to remember that situations like “is approaching 40 weeks gestation” or “large baby suspected” are not medical indications warranting induction per ACOG.
So how did epidurals impact VBAC rates? Surprisingly, those who received an epidural were 4.58 times more likely to have a VBAC!
It’s not surprising that among the people who labored with an epidural and then had a repeat cesarean, 43% experienced labor arrest as opposed to 24% among those who labored without an epidural and had a repeat cesarean.
Only 6% of those with an epidural requested a repeat cesarean during their labor whereas the rate was over 4 times higher (24%) among those who labored without an epidural.
Next, a 2019 multi-center prospective study out of China hypothesizes that those with epidurals have lower levels of stress hormones which can facilitate vaginal delivery. (Sun, 2019)
While they assert that epidural is a uterine rupture risk factor, their source for that statement – French obstetrical guidelines – clearly states, “Epidural analgesia must be encouraged.” (Sentilhes, 2013)
Sun did not report any ruptures among the 423 labors after cesarean in their study and thus concluded that epidurals, of which 263 received one, did not increase uterine rupture risk.
Like the previous study, they found a significantly higher VBAC rate among those who received an epidural (86% vs 70%).
ACOG’s VBAC guidelines on epidurals
Even as far back as ACOG’s 1988 VBAC guidelines, they state that there’s no reason to believe that epidurals are contraindicated in VBACs. If there was solid evidence linking epidurals to a delay in uterine rupture diagnosis, they would not make that statement.
Over the years, that recommendation has not waivered up through their most recent interim update in 2019 where they state: “No evidence suggests that epidural analgesia is a causal risk factor for unsuccessful TOLAC. Therefore, epidural analgesia for labor may be used as part of TOLAC.” (ACOG, 2019)
Additionally, they are clear there is no evidence to suggest epidurals interfere with uterine rupture diagnosis: “In addition, effective regional analgesia should not be expected to mask signs or symptoms of uterine rupture, particularly because the most common sign of rupture is fetal heart tracing abnormalities.” (ACOG, 2019)
What you need to know about epidurals and uterine rupture
In the end, here’s what we need to remember about planned VBACs, epidurals, uterine rupture, and abdominal pain:
The available research has not found that epidurals mask uterine rupture-related abdominal pain. Nor has the research found that epidurals delay uterine rupture diagnosis.
The most common symptom of uterine rupture is fetal distress indicated by bradycardia or other fetal heart rate abnormalities.
Finally, epidurals may be used during a labor after cesarean per ACOG and hospital policy should not withhold or require epidurals for planned VBACs. As ACOG (2019) says, “adequate pain relief many encourage more women to choose TOLAC.”
Given the lack of evidence, why do some providers, departments, or even entire hospitals have policies withholding epidurals from those planning VBACs? It is possible that there is simply confusion over what the evidence says? If that is the case, I hope this article helps clear that up.
It is also possible that hospitals with VBACs bans may see withholding epidurals as a way to get birthing people to not challenge the ban. They can either have their repeat cesarean with pain relief, or, if people decline that surgery, as is their right per ACOG’s (2019) VBAC guidelines as well as ACOG’s committee opinion on informed refusal, the consequence is labor without the option of an epidural.
This policy is not evidence based, though its coercive nature does carry the stink of paternalism and misogyny, neither of which have any place in healthcare.
American College of Obstetricians and Gynecologists. (2016). Refusal of medically recommended treatment during pregnancy. Committee Opinion No. 664. Obstetrics & Gynecology, 127, e175-82. http://www.acog.org/Resources-And-Publications/Committee-Opinions/Committee-on-Ethics/Refusal-of-Medically-Recommended-Treatment-During-Pregnancy
American College of Obstetricians and Gynecologists. (2019). ACOG Practice Bulletin No. 205. Vaginal birth after cesarean delivery. Obstetrics & Gynecology, 133(2), e110-e127. https://journals.lww.com/greenjournal/Abstract/2019/02000/ACOG_Practice_Bulletin_No__205__Vaginal_Birth.40.aspx
Fitzpatrick, K. E., Kurinczuk, J. J., Alfirevic, Z., Spark, P., Brocklehurst, P., & Knight, M. (2012). Uterine rupture by intended mode of delivery in the UK: A national case-control study. PLoS Medicine, 9(3). https://doi.org/10.1371/journal.pmed.1001184
Grisaru-Granovsky, S., Bas-Lando, M., Drukker, L., Haouzi, F., Farkash, R., Samueloff, A., & Ioscovich, A. (2018). Epidural analgesia at Trial of Labor after Cesarean (TOLAC): a significant adjunct to successful vaginal birth after cesarean (VBAC). The Journal of Perinatal Medicine, 46(3), 261-269. https://doi.org/10.1515/jpm-2016-0382
Guise, J.-M., Eden, K., Emeis, C., Denman, M., Marshall, N., Fu, R., . . . McDonagh, M. (2010). Vaginal Birth After Cesarean: New Insights. Rockville (MD): Agency for Healthcare Research and Quality (US). http://www.ncbi.nlm.nih.gov/books/NBK44571/
Johnson, C., & Oriol, N. (1990, Nov-Dec). The role of epidural anesthesia in trial of labor. Regional Anesthesia & Pain Medicine, 15(6), pp. 304-8. http://journals.lww.com/rapm/Abstract/1990/15060/The_Role_of_Epidural_Anesthesia_in_Trial_of_Labor.7.aspx
Nahum, G. G. (2018, Jul 5). Uterine Rupture in Pregnancy. Medscape Reference: http://reference.medscape.com/article/275854-overview
Sentilhes, L., Vayssière, C., & Beucher, G. (2013). Delivery for women with a previous cesarean: guidelines for clinical practice from the French College of Gynecologists and Obstetricians (CNGOF). European Journal of Obstetrics & Gynecology and Reproductive Biology, 170(1), 25-32. https://doi.org/10.1016/j.ejogrb.2013.05.015
Sun, J., Yan, X., Yuan, A., Huang, X., Xiao, Y., Zou, L., . . . Li, Y. (2019). Effect of epidural analgesia in trial of labor after cesarean on maternal and neonatal outcomes in China: a multicenter, prospective cohort study. BMC Pregnancy and Childbirth, 19(498), 1-13. https://doi.org/10.1186/s12884-019-2648-1
Zwart, J. J., Richters, J. M., Ory, F., de Vries, J., Bloemenkamp, K., & van Roosmalen, J. (2009, July). Uterine rupture in the Netherlands: a nationwide population-based cohort study. BJOG, 116(8), 1069-1080. https://doi.org/10.1111/j.1471-0528.2009.02136.x
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As an internationally recognized consumer advocate and Founder of VBAC Facts®, Jen helps perinatal professionals, and cesarean parents, achieve clarity on vaginal birth after cesarean (VBAC) through her educational courses for parents, online membership for professionals, continuing education trainings, and consulting services. She speaks at conferences across the US, presents Grand Rounds at hospitals, advises on midwifery laws and rules that limit VBAC access, educates legislators and policy makers, and serves as an expert witness and consultant in legal proceedings. She envisions a time when every pregnant person seeking VBAC has access to unbiased information, respectful providers, and community support, so they can plan the birth of their choosing in the setting they desire.