How Can I Increase My Chances of a VBAC?

You might be asking yourself, what can I do to increase my chances of a vaginal birth after cesarean (VBAC)? Here are a few newer studies I read and some thoughts about them.  (Please know, while I try to look at high quality studies, I am not a nurse researcher and this is in no way an extensive literature review.)

Two things to consider, birth location likely matters, and maternal/fetal weight gain impacts outcomes as well.  I think it is great the literature is reflecting birth location and outcome.  This is true for vaginal birth and cesarean in general, not just VBAC.  When possible, try to find information on birth settings in your area.  Pre-pregancy weight and pregnancy weight gain are not new.  This is something to pay attention to when planning for a VBAC.  I would say this is probably more important if you are planning a hospital birth rather than birth center/home birth.  Typical US hospital practices lead to immobility during labor. 

Hospital contribution to variation in rates of vaginal birth after cesarean  https://www.nature.com/articles/s41372-019-0373-2

In the most basic language – hospital matters.  Vaginal birth after cesarean section rates among Michigan hospitals varied greatly.  This is well known in New York as statistics are publicly reported.  In this link you can see which NYS hospitals have the highest VBAC rate by first selecting vaginal births and then vaginal birth after cesareans.  If you have a choice between hospitals you might want to make it based on this information like this.   

Practice variation of vaginal birth after cesarean and the influence of risk factors at patient level: a retrospective cohort study https://obgyn.onlinelibrary.wiley.com/doi/epdf/10.1111/aogs.13059

While not a USA based study, this one also points to hospital variation in rates. 

Factors associated with successful vaginal birth after a cesarean section: a systematic review and meta-analysis https://bmcpregnancychildbirth.biomedcentral.com/articles/10.1186/s12884-019-2517-y

This review included 94 studies, so there is a lot of information in it!  It is open access, so feel free to read through more thoroughly.  I will just highlight a few aspects that are potentially modifiable. 

Obesity & Fetal Macrosomia are more likely to result in an unsuccessful VBAC attempt.  If possible, maintain or obtain a healthy BMI prior to pregnancy.  During pregnancy pay attention to recommended weight gain. 

Gestational diabetes was also more likely to result in an unsuccessful VBAC. 

Avoid induction of labor if not medically necessary.  Gestational age did not impact outcome.  This is a good reminder to not fall into the belief that if labor doesn’t happen by XX (insert arbitrary number) gestational age, it isn’t going to happen.  Or that there needs to be a cut off of gestational age to be induced for a VBAC.  

 Vaginal birth after a cesarean delivery for arrest of descent https://www.tandfonline.com/doi/abs/10.1080/14767058.2018.1443069

Note - this study is small.  100 women attempted VBAC after a cesarean for arrest of descent (pushed, but baby wouldn’t descend), 84 delivered subsequently delivered vaginally!  In general 84% is considered a high success rate, but particularly after an arrest disorder, this is pretty incredible.  The authors conclusion was: This suggests that arrest of descent is mostly dependent on factors unique to each pregnancy and not due to an inadequate pelvis or recurring conditions. Women with a prior CD for arrest of descent should not be discouraged from attempting TOLAC in a subsequent pregnancy due to concerns about the likelihood of success.

I hope you are continually encouraged that the majority of women are candidates for VBAC! Access and support for VBAC are critical and in my opinion the biggest predictor of success.

If I Was a Betting Woman...

Twelve days late, for the third time.  Same weight gain for momma; for the third time.  Birth weight identical to one sibling and 2 ounces less than the other.  If I was a betting woman, I would start placing bets on my pregnancies.  That is if there were going to be a fourth one.  I am (almost) positive this is the last baby for us.  I think. 

Little Miss has arrived.

VBAC Series: Once a VBAC always a VBAC?

You may be wondering, if I have one VBAC what happens in my next pregnancy?  Am I still viewed as a VBAC? 

The short answer, is yes, with a uterine scar there are risks associated with each subsequent pregnancy.  The good news is these risks decrease with each additional vaginal birth after your cesarean section birth.  There is not much available in updated research and literature, but there was a secondary analysis of a large study that looked at over 13,000 women attempting a VBAC in 2008.

VBAC Success

Vaginal delivery was achieved in women who had no prior VBAC 63.3% of the time, one prior VBAC 87.6% of the time, and two or more VBAC’s 90.0% of the time.  There seemed to be no statistical difference once a woman had experienced two or more VBACs. 

Uterine Rupture

The risk of uterine rupture decreased from 0.87% of women with no prior VBAC to 0.43-0.45% in women with a prior VBAC. 

Other Risks Associated with VBAC

These risks also decreased with 1 or more VBACs

·       Blood transfusion

·       Blood clots

·       Uterine infection

·       Uterine dehiscence

·       Hysterectomy*

·       Poor neonatal outcomes*

·       Maternal death*

* showed downward trends that were not statistically significant

So while the answer is yes, once a VBAC, always a VBAC, there is reassurance in the risks to a VBAC are decreased after one or more VBACs.  And since these risks are low to begin with, perhaps the substantial rise in vaginal delivery after one successful VBAC is some of the most hopeful data gleaned from this study.  When staring down your first VBAC, one of the greatest questions is, “will I deliver vaginally”?  When facing your second VBAC, you can almost assuredly say, “yes I will deliver vaginally!”

VBAC Series: April is Cesarean Awareness Month

April is Cesarean Awareness Month.  This seems to be designated by the International Cesarean Awareness Network, but I can't really find anything about its origin. 

Part of awareness is knowing your hospital's cesarean section and VBAC rates.  Leap Frog Group collects information from hospitals about their first time cesarean section rate.  This is under the classification of cesarean section, which is not immediately obvious that it is referring to only first time mother's whose baby is in the head down position.   

Consumer Reports recently reported on the variation in hospital’s first time cesarean section rate based on the Leap Frog Group data.  Neighboring hospitals may have very different cesarean section rates.  While some hospitals may claim they have a higher risk population driving their cesarean section rate, this statistic is based on low risk mother's only, leaving no room for that argument. 

While many larger New York City hospitals declined to submit their data to Leap Frog Group, New York State collects similar information.  However, in the NYS data there does not seem to be a difference between high or low risk mothers.  Additionally, primary cesarean section rate may also include mom's who had a previous vaginal delivery, but had a cesarean section in a following pregnancy.  Even without the separation of low risk to high risk pregnancies, the data is somewhat telling, especially between large academic medical centers where patient population should be similar.  NYS data also contains information on their VBAC rate, defined as the number of women delivering vaginally with a previous cesarean section, the denominator is all women delivering with a previous cesarean section. 

Other states may have cesarean section data available.  In a quick search New Jersey and Massachusetts seemed to have reports on the information, rather than an interactive website.  Have information for your state?  Feel free to post a link to it in the comments below. 

VBAC Series: What Else Does ACOG Have to Say?

Despite the negative effects of the ACOG practice bulletin on vaginal birth after cesarean, the document does contain many positive points that are often ignored by obstetric care providers.  I encourage you to read the document if you are pursuing or deciding if you want to pursue a VBAC. 

Here are a few highlights:

1.     It is reasonable to attempt a trial of labor after cesarean if you have had two low transverse cesarean sections.  This is also true if the woman does not know what type of scar she has. 

2.     While macrosomia may increase the risk of uterine rupture, this alone should not solely make the decision of repeat cesarean.

3.     Going past her due date may decrease the likelihood of successful vaginal delivery, but this does not mean she should not attempt a TOLAC.

4.     Twins have similar success rate of VBAC as singletons.

5.     It is reasonable to induce or augment a TOLACs labor, but care should be taken in doing so.

6.     External cephalic version (attempt to turn a breech baby vertex) can be considered to avoid repeat cesarean. 

7.     Women can chose epidural analgesia as in any labor.

If you are finding your provider is putting multiple stipulations of on your pursuit of a VBAC (delivery by due date, only if baby isn’t thought to be too large, etc) you may want to compare their care to this practice bulletin.  In the end, you want a provider who believes VBAC is a good thing, rather than someone who will just “allow” it to happen under their strict criteria. 

VBAC Series: What Does ACOG Have to Say?

The American College of Obstetrics and Gynecology (ACOG) issued a practice bulletin in 1999 about Vaginal Birth After Cesarean.  Within this practice bulletin, providers were encouraged to counsel women regarding VBAC and the likelihood of their success, but that delivery should only occur in a setting where immediate emergency care can be offered.  While the first part of the recommendation is based on good scientific evidence, the second part of the recommendation is based solely on consensus and expert opinion. 

In 2010 a new practice bulletin was created, and this was reaffirmed in 2015.  The 2015 version starts by mentioning the large decrease in the number of women attempting a Trial of Labor after Cesarean (TOLAC).  In 1996 the number of VBACs reached 28.3% (that is the percent of women delivering vaginally after a prior cesarean), and now most sources put the VBAC rate around 10% nationally. 

Why the shift?  The ACOG bulletin states the increasing fear of uterine rupture and liability has led to the sharp decline.  However, they fail to mention their own statement about access to emergency care as part of the decline.  While there was a slow decline from 1996-1999, the decline steepened after the release of the 1999 practice bulletin.

In a 2007 paper in Birth journal, researchers called over 200 hospitals in their region, and found 30% had stopped offering VBACs based on the 1999 ACOG practice bulletin.  As a result access to VBAC has become far more limited in this area, and one could imagine this is also the case nationally. 

This report appears to have a great deal of information about VBAC and its safety, but I admit at 300+ pages, I have only begun to skim through it.  It also makes mention of this paper starting the decline of VBACs (check out the graph on page 12 of the report) in addition to the ACOG practice bulletin. 

The ACOG practice bulletin has MANY good points about VBAC and how the majority of women are good candidates for a trial of labor.  What is unfortunate, though, is how a single statement based on consensus and expert opinion, rather than scientific evidence, has done so much to shape access to a TOLAC. 

VBAC Series: Finding Support

Any woman planning a VBAC knows the support for her decision is of utmost importance.  Ideally this support would be found in her family and care provider.  However, this might not be the case for each woman planning a VBAC or she would simply like to connect with someone making the same decision.

There is little to no research about the supportive environment affecting the rate of VBAC, but for those who have been through the experience, support is one of the key factors of successful VBAC. 

In the day and age of social media, many women are turning to online communities to find the support they desire while planning a VBAC.  In a recent article from the Journal of Perinatal Education, a childbirth educator describes the online support she saw for a woman who attempted a VBAC and ultimately ended up with a tertiary cesarean section.  Strangers followed this woman’s story, and hundreds commented on her posts during labor. 

Another journal article analyzed a VBAC forum and pregnancy forum on babycenter.com.  The VBAC forum appeared more personal and supportive than the pregnancy forum based on their scoring criteria.  

You may want to consider the following when joining an online group:

1.     Size.  Are you looking for a more intimate group where members know each other well or a larger group that might have more activity.

2.     Moderation level.  Some groups may have a monitor that deletes inappropriate comments or off topic threads. 

3.     Privacy.  Is it a closed group or open to the public?  How are members approved?

4.     Types of questions asked.  This will probably be mixed in all groups, but overall are members looking for support, medical advice, or general information. 

5.     Usefulness in your own life.  Does the group bring you the support you are looking for, positiveness to your situation, or just a fun distraction?

There are no right or wrong answers to the considerations above.  It is all based on personal preference and determination of value in your own life.  If you are looking for extra support when pursuing a VBAC or want to hear from someone else going through the same situation, an online group may be a viable option. 

VBAC Series: Weight Gain, How Much is Too Much?

With each of my pregnancies I have gained the majority of my weight in the second trimester.  As many women gain their highest amount in the third trimester or at least maintain a steady weight gain, this had myself and my providers nervous in the past. 

The first time around, I was the nervous one.  However, if memory serves me correctly, I didn’t gain any weight after 32 weeks and found myself delivering at the low end of my pre-pregnancy weight gain recommendation*.  The second time around, it was my providers who were a little nervous.  At 26 weeks I had gained 19 lbs, and was on track to gain about 35 lbs if the momentum stayed the same throughout my pregnancy.  Somehow I found myself at the exact same weight gain as my first when delivering my second.

This time around I am on a similar weight gain pattern, and if history serves me well, the weight gain should start to slow down soon.  But with my first VBAC pregnancy, I had to ask myself, why does my provider care so much if I gain 35 lbs?  At the time I did a literature search and found gaining weight above the Institute of Medicine’s recommendation was negatively associated with successful VBAC.  I was curious to see if any new literature had surfaced since that time.  Here is what I found. 

This article studied women considered high-risk during pregnancy, classified by hypertension, diabetes, and/or obesity.   The researchers found women who gained more than the weight gain recommendations were less likely to have a VBAC.  The abstract states the weight of 30lbs, but I did not find this specification in the article, just the description of exceeding recommended weight gain based on pre-pregnancy BMI.  The study did not seem to consider pre-pregnancy BMI and weight gain separate from the other high-risk factors, though the majority (63%) in the study were obese.  What I mean by this is, was the weight gain more impactful if the woman was already obese?

This article looked at pre-pregnancy BMI and weight gain.  Both obesity and excessive weight gain, 40lbs in this article, were negatively associated with VBAC.  The abstract spells out the different rates. 

I found this article a little bit difficult to follow.  In the abstract the authors state a BMI >25 is significantly associated with a decreased success rate.   While, it never states when the BMI was measured, I can only assume that it is the labor admission BMI, as all of the other variables measured were upon labor admission (gestational age, cervical dilation, etc.).  Essentially, only 20% of those in the successful VBAC group had a BMI >25, while 58% of those in the failed VBAC group had a BMI >25.  The amount of weight gain that this would relate to varies, depending on a woman’s starting BMI. 

Lastly, this article discussed weight gain between the first and second pregnancy.  An increasing BMI between pregnancies was associated with a decreased success rate, and a decreasing BMI in women who were overweight or obese before their first pregnancy was associated with a higher success rate.  If you aren’t already pregnant, and are planning a VBAC with your next pregnancy, you may want to pay attention to your inter-pregnancy weight. 

To be clear, none of the authors stated that a high weight gain or BMI at the time of delivery was an indication to have a planned repeat cesarean.  They were only exploring factors associated with a successful VBAC.  That said, it may be prudent to only gain within the IOM’s recommendations for pregnancy weight gain while planning a VBAC. 

*every woman's weight gain pattern varies during pregnancy.  My own story is not an example of how it should/should not be done. 

VBAC Series: VBAC Calculator, is it accurate?

If you are planning a vaginal birth after cesarean (VBAC), you may have come across a VBAC Calculator.  The VBAC calculator attempts to take variables* into account and predict the likelihood of vaginal delivery after a cesarean. 

Before you break down in tears, especially if you have never had a previous vaginal delivery, lets consider a few things.  A recent Letter to the Editor in Birth: Issues in Perinatal Care critiqued the use of this calculator.

An interesting point to consider is that the risk of perinatal death or hypoxic-ischemic encephalopathy in the newborn is 1 in 2000 for a woman attempting a VBAC.  Even if a women’s likelihood of successful vaginal delivery is low, her risk of poor outcomes for her baby is extremely low if she does not have a VBAC in the end.  Additionally, the authors pointed out that we don’t use a calculator to determine if a woman with no prior deliveries will have a successful vaginal delivery, though there are certainly factors that influence this. 

Multiple studies show that the actual success rate of a VBAC is somewhere around 74%, and this increases to 94% if the woman has had a prior vaginal delivery.  VBAC calculators are more accurate the closer to delivery used, rather than the start of a pregnancy.  There is a second calculator that takes into account hospital admission factors, gestational age, cervical exam, etc.  I was unable to find a link to a public website containing this calculator, but will update this page if I do. 

I think the VBAC calculator fails to take into account a variable that I personally believe has a huge impact, the support of your provider.  While some providers may initially promise the backing for a VBAC, their support may wane over the course of your pregnancy.  A gestational age or predicted estimated fetal weight cut-off, strict monitoring in early labor or an epidural “just in case” may be signs your provider isn’t as supportive as they may say.  Similar, a hospital setting that is not supportive of VBAC can also deter a woman’s outcome of VBAC.   A woman in a supportive environment with a low prediction of vaginal delivery might just be more successful than another in an unsupportive environment with a higher prediction of vaginal delivery.  Wouldn’t it be interesting if the provider’s and hospital’s VBAC rate was added to the calculator!

When I use the VBAC calculator to predict my VBAC a few years ago, I received a likelihood of 65% and without the patience of my providers it probably would have been 0%.  This time the calculator predicts 91%, slightly less than what research shows.  But with the same supportive providers, barring an emergency, I think the likelihood is much higher. Only time will tell!

Curious if anyone else received a low likelihood of success and went on to have a vaginal delivery.  What did you find to be the biggest impact on your outcome?

* BMI is the pre-pregnancy BMI, not current.  The second hospital admission calculator takes into account the current BMI

VBAC Series: Vaginal Birth After Cesarean (VBAC) Resources

On a personal note, I had a cesarean section with my first child.  Two and a half years later I had a vaginal birth after cesarean, commonly shortened to VBAC.  During that time I searched the Internet tirelessly looking for resources, stories, anything that would lead me to remain hopeful or perhaps increase my chances of success. 

While there were a few solid resources, I wanted more!  My hunger for information could not be satisfied.  Now two years later, I was curious to see what was still out there and if there was anything new.

Here is my round up:

www.vbac.com

This website has become a wealth of knowledge.  I haven’t even scratched the surface of her new resources.  As far as I can tell, it all looks free.  I look forward to reviewing her new The VBAC Education Project. 

www.vbacfacts.com

I was hoping this website would be a little easier to navigate after a few years, but while it has been updated, I am not in love with the format.  There still seems to be a great deal of information on the website, just a little buried.   Jen Kamel (the creator) has workshops around the country, and they look well worth cost/time. 

American College of Obstetrics and Gynecology (ACOG)

ACOG has practice bulletins, which should guide obstetricians practicing in the United States.  They are in support of VBAC, and their guidelines are far less restrictive than how most obstetricians practice. 

NIH Consensus

Another position paper in support of VBAC

Childbirth Connection

Overall, this is a solid website that focuses on evidence based care.  There is a good deal of information about VBAC and repeat cesarean.  While I do think the information is good, I want to point out that the last time this section was updated was 2012. 

International Cesarean Awareness Network

A website dedicated to providing resources to women who have had a prior cesarean.  They also have local chapters where women who have had a cesarean can meet together. 

www.trialoflabor.com

This is a documentary that explores a women’s journey to VBAC.  Definitely worth the watch.

Ina May's Guide to Childbirth

This book is not specific to VBAC, but there are a few stories about VBAC in it.  The most important part of this book is the normalization of childbirth.  Ina May Gaskin is an amazing birth advocate, this is a must read.

 The Official Lamaze Guide: Giving Birth with Confidence

Another good read that normalizes birth.

Many websites have a page or two dedicated to VBAC, but these resources dig deeper, fully aware that knowledge is power when pursuing or deciding about a VBAC. Is there anything I missed, a resource you found particularly valuable to your journey?