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Vaginal Birth After C-Section: An Einstein Perspective

By on 08/23/2019

For many years, it was common medical practice for women with a previous cesarean section to have a C-section again for any future pregnancy. More recently, however, vaginal birth after C-section (VBAC) has become an option for increased numbers of women.

Among U.S. women with a previous cesarean birth, 12.8% gave birth vaginally in 2017, according to the U.S. Centers for Disease Control and Prevention.

Einstein Healthcare Network produces numerous podcasts featuring our doctors and experts discussing their fields of medicine and sharing tips on how to live a healthy life.

In this podcast, Cheung Kim, MD, Chief of Obstetrics and Gynecology at Einstein Medical Center, Montgomery, talks with Perspectives’ Sharon Eisenhour about the potential benefits and risks of VBAC.

Sharon Eisenhour: Welcome to Einstein Perspectives. I’m Sharon Eisenhower and I’m speaking today with Dr. Cheung Kim, Chief of Obstetrics and Gynecology at Einstein Medical Center Montgomery. Today we’re talking about vaginal birth after C-section, and you call that VBAC, and welcome Dr. Kim.

Dr. Kim: Thank you for having me here today. Appreciate it.

Sharon Eisenhour: So traditionally women have been told that if they had a cesarean delivery for one baby, any future babies also must be delivered by cesarean. So why is that?

Dr. Kim: I think that whenever there’s a major surgery to the uterus, the theoretical idea was that the structure, the walls were compromised, so that for future pregnancies and the whole labor process, that there might be a risk of the uterus rupturing in labor. And so, that was the original thinking, and that’s what led to the “once a C-section, always a C-section” back a long time ago.

Sharon Eisenhour: Yeah, that is what we used to hear all the time. So what is the vaginal birth after cesarean delivery, exactly? Or, as we call it, VBAC.

Dr. Kim: Right. VBACs are the ability to have a successful delivery after a woman’s had a C-section, of having a vaginal delivery with subsequent pregnancies. And that’s something that we look at very carefully in terms of the circumstances surrounding why they had the C-section, and then how the next pregnancy and subsequent pregnancies are. It’s an important decision that a mother has to make because it probably limits her choices for pregnancies if she goes beyond those two.

Sharon Eisenhour: Well, what is a trial of labor after cesarean delivery? And you call that TOLAC, I think.

Dr. Kim: That’s right, trial of labor after cesarean. A TOLAC is when a woman has chosen to see if she can have a vaginal delivery after having a prior pregnancy that involved a cesarean. And a lot of factors are taken into account, to make sure that she is an adequate candidate and that it’s something that would be safe for her. So if you have a patient who tries to TOLAC and she’s successful, then she is a VBAC. And that really changes the evaluation of a patient for future pregnancies. And we tend to feel that once someone’s been able to achieve a vaginal birth, that the possibility of doing that in the future is much higher. So we really strive to allow people to have a trial of labor if they’re a good candidate.

Sharon Eisenhour: So what are some of the benefits of having a VBAC?

Dr. Kim: Well, the first benefit, certainly, is that you don’t have to have abdominal surgery again. And what’s associated with that, as you can imagine, are there’s less blood loss associated. Surgery generally has on average a two-fold blood loss compared to a vaginal delivery. And you have a shorter recovery. Most people are amazed when they can just leave the hospital within 24 hours. Or now, in the 21st century, the idea of a home birth and just being up and around hours later is starting to become more the norm. And certainly, things like infection rates are lower, probably more related to the fact that you’re avoiding abdominal surgery. Equally important, as we talked about, was future pregnancies are very much affected by whether someone’s able to have a VBAC. Once that’s happened, it really allows the clinician and the patient to try to facilitate future VBACs.

Sharon Eisenhour: Are there risks to a VBAC?

Dr. Kim: There’s certainly are. One is, we go back to some of our old-fashioned ideas of the three P’s in obstetrics: the power, the passenger and the passage. And those three variables involve the strength of labor, the bony pelvis of the mother and the size of the baby, whether it’s small or big. And if those criteria are less than favorable, a woman can find herself in an extended period of labor without success. And those increase the risk of issues with the baby and the baby’s health while in labor, and increase the risk of infection for the mother, and this is all with just trying to be in labor. And VBAC is quoted as having a 1% chance of the uterus rupturing for those people who are ideal candidates. And that number is probably more realistically on the order of a fraction of 1%. but we always counsel people about that theoretical risk. So sure, trying to be a VBAC candidate, it has some consequences, and we make sure that people are well informed about that.

Sharon Eisenhour: What types of hospitals are able to offer VBAC, and for what groups of patients?

Dr. Kim: There are certain institutional criteria. You have to have people readily available for emergencies, as you can imagine, because sometimes this process can turn very quickly. And so, a number of institutions don’t allow patients to have a trial of labor or attempt a VBAC. And so, what we do is we promote that for those people who are ideal candidates, and there are candidates who aren’t. One of them would be someone who’s had a vertical incision on the uterus, because the risk of rupture far exceeds the chances that they’d be successful. So those are people who are not candidates.

Sharon Eisenhour: Why is the type of uterine incision that’s used in the previous cesarean delivery important?

Dr. Kim: The uterus is sort of like a lattice work of muscles crisscrossing in all different directions, and its greatest strength tends to be in the horizontal fashion. So we prefer to make what we call a transverse or horizontal incision, because that has the greatest strength and therefore the lowest risk of rupture. If you make a vertical incision, you’re really compromising the integrity of the uterus and the musculature, and that’s why there’s a greater risk of the uterus itself rupturing in labor. Labor’s pretty intense, if you talk to most people who’ve been through it, and it’s probably a reflection of just how strong the muscle is contracting. And so, those types of incisions, any sort of a vertical incision, is what we call a contraindication or would not allow someone to be a candidate for a trial of labor.

Sharon Eisenhour: Okay. And are there things that can happen during labor that may change the delivery plan? I mean, would that ever be possible or necessary?

Dr. Kim: Absolutely. Yeah, I mean people without risk factors or prior incisions, encounter similar circumstances where labor is a mystery. The mother, the fetus, the infant might not be able to tolerate labor in those circumstances. And when someone has a little bit of a handicap with a prior C-section, we watch them a little bit more carefully. And I think that that’s because at any time, the fetus or the mother or her body could demonstrate that there’s a problem that’s going on. And that’s why one of the requirements for being an institution that allows trial of labor after cesarean is that they be able to do emergency acute surgery to deliver the infant.

Sharon Eisenhour: Very, very interesting. Do you have any other thoughts that could enlighten our listeners?

Dr. Kim: I think that the most important thing that we try to promote is having a natural, low intervention first pregnancy, because that sets the tone if you’re blessed enough to have more children down the line. And I think that’s something that our group really promotes and does a really good job with. We have good, good success rates there. Also, I think it’s nice to be able to point out, and I’m proud of this, that in our institution we have a very low C-section rate. Not just for the region, but for the country. And I think it takes a lot to achieve that. And that’s a particularly proud statistic that I like to share with the listeners.

Sharon Eisenhour: Well, I’d like to thank you so much for being with us, Dr. Kim.

Dr. Kim: Thank you. It’s been a pleasure.

Sharon Eisenhour: I’ve been speaking with Dr. Cheung Kim, Chief of Obstetrics and Gynecology at Einstein Medical Center, Montgomery in East Norriton. I’m Sharon Eisenhower for Einstein Perspectives. Learn more about Einstein’s obstetrical and gynecological services at

1 Comment
  1. antoinette


    Thanks for explaining the importance of previous uterine incision for pt who desire TOLAC

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