Does it matter that VBAC significantly increases the risk of poor maternal and neonatal outcomes compared to repeat C-section?

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A new paper published this month in the Canadian Medical Association Journal, Mode of delivery after a previous cesarean birth, and associated maternal and neonatal morbidity, shows that attempted vaginal birth after C-section (VBAC) significantly increases the risk of poor maternal and neonatal outcome.

Absolute rates of severe maternal morbidity and mortality were low but significantly higher after attempted vaginal birth after cesarean delivery compared with elective repeat cesarean delivery (10.7 v. 5.65 per 1000 deliveries, respectively; adjusted RR 1.96, 95% CI 1.76 to 2.19). Adjusted rate differences in severe maternal morbidity and mortality, and serious neonatal morbidity and mortality were small (5.42 and 7.09 per 1000 deliveries, respectively; number needed to treat 184 and 141, respectively).

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The study confirms what we’ve known for sometime. Successful VBAC is safer than elective repeat C-section, which is much safer than failed VBAC.

Should we be so desperate to lower the C-section rate?

The authors explain:

Vaginal birth after cesarean delivery is increasingly contentious as rates of cesarean delivery rise and prior cesarean delivery serves as the most common single indication for a cesarean delivery. Planning mode of delivery for women with a previous cesarean delivery is challenging both for the patient and the care provider. An elective repeat cesarean delivery is associated with an increased risk of surgical complications, as well as an increased risk of abnormal placentation in subsequent pregnancies. On the other hand, attempted vaginal birth after cesarean delivery is associated with a higher risk of uterine rupture and other maternal and infant complications.In addition, a substantial proportion of women attempting a vaginal birth after cesarean delivery will require an emergency cesarean delivery, which increases the risk of maternal and infant complications.

The question is: should this matter to our desperate efforts to lower the C-section rate?

We are currently living through a moral panic about the C-section rate. To hear partisans of “normal” birth tell it, the current C-section rate of 32% is nothing short of a medical scandal even though there is considerable evidence that C-section rates of over 40% are entirely compatible with low rates of maternal and neonatal mortality and morbidity. Nevertheless we are continually exhorted that the C-section rate must be reduced.

One of the ways to reduce the current C-section rate would be to increase the rate of attempted VBAC. VBAC rates were essentially 0% back when all incisions on the uterus were vertical. Because of the high risk of uterine rupture in a subsequent labor, the mantra of “once a Cesarean, always a Cesarean” held sway. As horizontal incisions on the uterus became standard of care, and the rupture rate dropped dramatically, VBAC became quite popular. When I was practicing I, like my colleagues, offered a VBAC to every woman with one previous C-section. Nearly 80% of the attempted VBACs were successful.

In the 1990’s large scale data collection, along with spectacular malpractice settlements, demonstrated that the risk of ruptured uterus after a previous horizontal uterine incision was dramatically smaller, it was emphatically not zero. This study confirms those findings.

The authors note:

The evaluation and interpretation of risks associated with attempted vaginal birth after cesarean delivery presents a challenge because risk perspectives vary widely. Both the relative increase in rates of severe maternal and neonatal morbidity and mortality after attempted vaginal birth after cesarean delivery compared with elective repeat cesarean delivery and the absolute difference in these rates need to be weighed carefully before a decision is made about whether the excess risks are acceptable or high. In additional, women planning large families need to be cognizant of the risks of morbid placentation in subsequent pregnancies, because such risks increase with repeated cesarean deliveries. These inputs into decision-making may also be affected by desire for vaginal birth, the severity of the outcomes in question and other personal valuations. Health care providers need to help women to contextualize risks better so that they are able to make informed and personalized decisions.

There is nothing wrong with a high C-section rate in and of itself. A high C-section rate is perfectly compatible with low rates of maternal and neonatal mortality and morbidity. Every woman should be counseled that successful VBAC is safer than elective C-section, which is much safer than failed VBAC. However, the chance of successful VBAC varies from women to woman and from pregnancy to pregnancy and that, too, will be a factor in decision making.

Different women will assess the importance of individual risks differently. The job of obstetricians is NOT to lower the C-section rate but rather to deliver healthy babies to healthy mothers while respecting women’s right to make decisions about their own bodies. It is never appropriate to privilege a process — in this case vaginal birth — over the outcome.

  • Amazed

    OT: My friend with the 30-weeker made me laugh today. About two weeks ago, there was a fire somewhat close to the hospital. It didn’t reach this far but the babies were moved to another wing for safety. And for swiftness’ sake, there were some cases of two babies being transported in one isolette. Two of those were twins and during their trip, they somehow found the time to realize that they were not happy sharing the space, so they fought it out to determine who the rightful occupant was. Neither of the two fighters was heavier than 3 pounds but they were no less fierce for it!

    • Empress of the Iguana People

      If this were FB, I’d definitely have used the laughing icon! Lord knows it won’t be the last sibling fight

      • Amazed

        I wonder what it was like for the first battlefield, otherwise known as mom!

  • Roadstergal

    Am I reading that right? Even with a successful VBAC, some of the maternal and neonatal outcomes still favor repeat scheduled C/S?

    • mythsayer

      I think it’s because the RISK of a failed VBAC is more dangerous than a RCS, which overall makes RCS safer….? Pretty sure that’s what’s she saying. If you SUCCESSFULLY VBAC, it is safer than a RCS, but if you fail, it’s much worse, so overall, the risks of RCS are quite real. That’s how I read it.

      • The Bofa on the Sofa

        But what Roadstergal is seeing (and it’s there) is that even in the results for the SUCCESSFUL VBAC, there are outcomes for which the c-section was better. The VBACS was significantly better in a few things expected, like respiratory distress syndrome for the baby and uterine rupture (because it was successful, you have selected those VBACS that did not have uterine rupture) and restricted morbidity for the mother (c-section patients necessarily have incisions that have to heal), but there were other outcomes that were better with the c-section, like pph for the mother and assisted ventilation for the baby.

        Now, the degree of benefit and the seriousness of the issues involved might not be equal, and hence you can argue that the successful VBACS is better overall, but even in that case, there are goods and bads.

        And that just applies to the successful VBACS, not the overall, much less the unsuccessful.

        • Roadstergal

          Yup, that’s what I was getting at. The numbers aren’t huge, but there are outcomes that are better with C/S even compared to a successful VBAC – and that’s part of informed consent.

    • fiftyfifty1

      The one outcome I wondered about that I couldn’t find addressed in the paper are fetal deaths while waiting to go into labor. If you choose a repeat CS, they typically do it at 39 weeks. But if you want a VBAC they will usually wait until you go into labor naturally which may be at perhaps 40 weeks. We know that a certain number of intrauterine fetal demise (IUFD) cases statistically will occur between 39 and 40 weeks (or whenever the woman goes into labor naturally.) These stillbirths may then be born by CS (“failed VBAC”) or vaginally (“successful VBAC”.) Are these deaths included I wonder?

      • Amazed

        OK, I understand it’s medical terminology and all, I truly do. But to this layperson, the words “a successful VBAC with a stillborn” sound creepy as hell. It has nothing do do with medicine. I’m just creeped out that a process where a woman pushes out a dead baby can ever be considered successful. Especially when I know that it actually is… by a not so small number of non-medical, au naturel people.

        • Glia

          I talk about my second kid’s birth as my failed TOLAC/successful birth sometimes, for that reason. I can’t bear to call the safe birth of my perfect, healthy baby a failure! I’m not delusional, I know that’s what people call it, but still, I got a baby! Resounding success!

      • Mimc

        Around here they wait til 41 weeks. They also wait until 41 weeks to induce which was a problem for me because my placenta had started to fail in that last week. That’s why my baby almost died and had to spend a week in the NICU. I’m leaning toward repeat C-section just so they won’t let it go that long next time. Although I’ve got a few years to decide.

  • OT:
    Some of the most profound investigative journalism about sexual assault ever to air on Australian TV.

    I strongly encourage everyone to watch and share it, regardless of where you’re from – this is a discussion that needs to happen everywhere.

    https://www.youtube.com/watch?v=1WVCscJZgiI

    • Who?

      Yes wasn’t it thought-provoking.

      My son is a police officer and this defence causes him to despair-and then get very cranky indeed. A police officer in Queensland recently avoided a conviction for rape based on this defence. It leaves any case other than dragged away, beaten and raped very difficult to prove.

      • Mishimoo

        I haven’t had the energy to watch it, mostly because it hits too close to home. We don’t associate with a relative (except accidentally) on my husband’s side because the lovely fellow managed to dodge a rape conviction by thoroughly smearing the poor unconscious victim’s name. I hate rapists.

      • It’s infuriating isn’t it.
        How was this ever not illegal?

  • Guest

    I am one of those women who is pregnant, and assessing the risks. My OB says I am a perfect candidate for VBAC. However, with my first pregnancy I failed at vaginal labor, then almost died due to complications in surgery while undergoing an emergency C-section. I know the chances of a repeat of either scenario are low, especially if I have an elective C-section, but I still feel like I am caught in a catch 22. I feel like the OBs at the local hospital are heavily pressured to promote vaginal over cesarean delivery, and I wish I could just get a straight answer about which is the safer option for the baby, given my medical history.

    • attitude devant

      Well, no one can give you advice without really going over your chart and examining you. What complications did you have from c/s?

      • Guest

        I’m not really expecting medical advice over the internet, more lamenting the fact that I can’t tell what is honest advice from the hospital medical staff, and what is driven by their BFHI/trial of labor policies.

        I was given these big speeches about how important it was to attempt vaginal (“natural”) birth again and what a high success rate of VBAC they had. Then almost as an afterthought my OB told me that the hospital had cleared me for an elective c-section, given how absolutely poorly the first attempt at vaginal birth went. Maybe they are just trying to provide me with choices, but it seems confusing and contradictory.

        • MaineJen

          It makes me really mad that the natural birth ideology has so permeated the OBGYN culture that you can’t get a straight answer any more.

          I will just say…of all the women I know who have had primary c sections, only one ended up doing a VBAC for their second baby, and that one was a “surprise” VBAC in which the baby came so quickly there was no time for surgery! In every other case, the second c section was scheduled for pre-labor. And in every case, the woman describes it as quick and complication-free, and much much MUCH easier than her first c section.

          I know this is anecdata. But I also know that if it was me, and if my first c section happened after a horrible trial of labor (as it sounds like yours did!), I would not be choosing VBAC.

          • crazy mama, PhD

            I had a VBAC by choice with my second baby and I’m happy with how it went. The short-term recovery was much easier for me.

            HOWEVER, my original C-section was pre-labor, for a breech baby, and that was one of the big reasons I was considered a good candidate for VBAC. I’m extremely surprised that an OB is telling someone who had a complicated labor and difficult surgery that she is a perfect VBAC candidate.

          • swbarnes2

            Maybe the “difficult surgery” part is part of why the OB is saying “let’s try a non-surgical option first”?

          • Daleth

            Emergency CS is basically always more difficult than planned, prelabor CS. The surgery itself is more difficult, the anesthesia is often more difficult (placing a spinal block in a laboring woman when time is short vs. in a non-laboring woman when there’s no emergency) and more dangerous (OP, did you get put under with general anesthesia?).

            And that’s just the surgery, not even counting the fact that mom and baby may both be exhausted and medically compromised by the time you get around to doing the emergency CS. And the OP here said she’d already had an anaphylactic reaction to meds given during labor. When you add those factors in you get a much higher complication rate.

            Without seeing her chart no one can be sure, but my guess is it’s not at all because of that prior difficult surgery that they’re keeping the VBAC option open. Comparing an emergency CS in a medically compromised laboring woman to a planned c-section done before labor is comparing apples and oranges. There’s just no comparison.

          • Guest

            Well, both of my pregnancies have been very low-risk and healthy. My labor started quickly the first time and everyone expected it to go well. Then it stalled, and every intervention they tried led to an unexpected adverse event, including an anaphylactic allergic reaction to one of the meds. I can’t fault the hospital staff – they did everything by the book. It was just a case of freakishly bad luck.

            I guess the expect the second one to go a bit smoother? Or maybe they are trying to avoid surgery for me again. I don’t know.

          • Daleth

            My labor started quickly the first time and everyone expected it to go well. Then it stalled, and every intervention they tried led to an unexpected adverse event, including an anaphylactic allergic reaction to one of the meds.

            FWIW, with that history there is not a chance in hell that I would attempt a VBAC. I would sign up for a full-term planned, pre-labor c-section as soon as I got a positive pregnancy test!

          • Roadstergal

            Yeah, that’s the thing. You can’t choose to have a VBAC. You choose to have either a VBAC or a C-section post-unsuccessful attempt.

          • Anna

            Yes, choice is an illusion in birth really.

        • Allie

          I found sometimes that even though the doctor was giving me all the choices, she was making a huge effort not to try to sway me in one direction or another, which annoyed me, perhaps even more so than if I thought she was giving me the party line. Not about VBAC (I am one and done), but about induction. I was AMA and because I had IVF, I knew when my LO was conceived, practically to the hour. I was leaning toward induction exactly at 40 weeks, and she refused to confirm that she felt it was the right choice in my circumstances, although she finally put me out of my misery after I agonized over it. I get that her job is to provide me with the risks and benefits and let me make the decision, but I don’t think it’s an interference with my autonomy for her to tell me what she would recommend. In the end, I was scheduled for it, but ended up going into labour the day before.

          TL;DR: doctor was great about outlining risks and benefits, but I also wanted some guidance.

          • Anna

            Yes, sometimes I just want to be able to say, you’re the expert, what should I do? I had a go at playing expert myself and I fucked it up and I live with the consequences. I can tell you, empowering it ain’t!

          • guest

            Yes! This describes the frustration quite well.

            There has been so much talk and so many questions about what birth experience I want. I just want them to tell me what choice they think is the least risky.

    • Montserrat Blanco

      For the baby it will be a C-section. The only complication that is higher for CS babies is distress respiratory syndrome. It is less frequent than vaginal birth complications, so, statistically the baby will be better off with a CS. For you… it depends. If you are sure you want a big family, I would consider VBAC, because risks with CS increase depending on the number of CS. If you are sure you want two-three children the most, then I would go for the CS, as the rate of complications for you will be acceptable.

      In any case if your OB is favouring vaginal vs CS in your particular case, it is highly likely a VBAC will go smoothly ( I am assuming you will be T the hospital in case things start to head south). Best of luck with your chosen path.

      • swbarnes2

        The thing is, the poster doesn’t know if she really is a good candidate. She’s not sure that her doctor would honestly say “VBAC for you is iffy” if that’s what the facts suggest.

    • J.B.

      I think you would be best served by coming up with a specific list of questions – starting with why (s)he thinks you’re a “perfect candidate”. What negatives does (s)he see happening with either option? Also maybe talking through the sequence of events – if you tried for a VBAC at what point would you call it quits?

      If your only feeling about VBAC is revulsion or fear then that is a perfectly valid reason to schedule a C section.

  • Dabbledash

    Couldn’t this be stated more broadly as “Successful vaginal birth issafer than elective C-section, which is much safer than failed vaginal birth.”

    • Daleth

      We could, but that would be meaningless, because nobody gets to choose to have a successful vaginal birth. The only actual choices are (1) attempting VB, which in the case of VBAC has a high risk of resulting in an emergency CS; or (2) getting an elective c-section.

      IOW it is misleading to separate successful from unsuccessful vaginal births. It’s like separating road trips that didn’t end in car crashes from road trips that did end in car crashes, and then saying “road trips that don’t end in car crashes are safer than traveling by plane.” Um, of course they are–because you just removed all the car crashes from the road trip group, while leaving all airplane travel–including the trips that ended in crashes–in the airplane group.

      • The Bofa on the Sofa

        Or drunk driving. Drunk driving is perfectly safe if you ignore the times it ends up in an accident or arrest.

        Break down the stats for successful drunk driving and unsuccessful drunk driving, right?

        • Daleth

          Exactly. “Successful drunk driving is safer than riding a motorcycle while sober, but riding a motorcycle while sober is safer than drunk driving that ends in a car crash.” That is just straight up USELESS information.

          • Who?

            Thing is, if you said it fast enough it might just sound like information-particularly if delivered with authority.

            We all need to be better at hearing what is actually said.

            All for informed consent for VB by the way, but think it would be pretty hard to hear-birth is one of those things we all assume will go well until something comes up for us or someone close.

          • Daleth

            Probably part of the reason we assume birth will go well is that doctors and midwives don’t warn us of the risks. No informed consent = no information.

        • Roadstergal

          “VBAC vs CS – do ya feel lucky, punk?”

  • attitude devant

    But this is not news, right? We’ve always known that VBAC per se is pretty safe. The complications are clustered in the failed moms who failed TOLAC, and that the risks are disproportionately borne by the infant. Women are poorly served by the fantasy that birth is inherently safe. It isn’t, and failure to acknowledge the risks is fraud on a gender-wide scale.