One critical conclusion is that there is no single right answer on estimating the probability of any individual attempting VBAC. It saddens me to think that many parents have not been given a chance for TOLAC because of a lower VBAC score. While the number of participants is small, and more research still needs to be done, you can see how inherently flawed these numbers can be. As you look at the numbers, pay close attention to the “Calculated VBAC Score” and compare it to the “Actual VBAC Success Rate.” Image source: American Journal of Obstetrics and Gynecology I absolutely love these charts from the AJOG journal, which break down the numbers from the study referenced above using both the score-based and percentage-based calculators. Let’s break it down. Your VBAC score can either be a number (0-25) or, a percentage (out of 100%). those who would not, I was surprised to see the data. While I know the calculators were more likely to predict those who WOULD achieve a VBAC vs. Are prediction models for vaginal birth after cesarean accurate?. In 2019, a cohort study was performed to see if predicted rates for VBAC were accurate. The decision to attempt TOLAC is a preference-sensitive decision, and eliciting patient values and preferences is a key element of counseling.
It is ill-advised to use statistics as a primary indicator when making VBAC decisions.Ī predicted success rate of less than 70% is not a contraindication to TOLAC. The ACOG bulletin also focuses on how population-based statistics cannot accurately predict an individual’s VBAC success odds. ACOG and the VBAC CalculatorĪCOG Practice Bulletin 205 discusses using the VBAC calculator for providers when counseling patients who want a VBAC:Ī VBAC calculator may be used to provide more specific information about the chance of VBAC, which can be used to further the process of shared decision making.” (emphasis added) I also posted a video, the exact one we use in our VBAC course for parents, playing around with the calculator so you can see its inherent flaws. She ended up pushing her baby out in twenty minutes.Ĭurious to see what your success rate is? Play around with the VBAC calculator and adjust different variables to see how it impacts your “chances” of VBAC. One of my favorite VBAC stories is of my first doula client, who was given a 4% (yes FOUR) chance of success by her provider using the VBAC calculator.
This calculator has limitations and should not be the sole decision-maker regarding a woman’s decision to attempt a VBAC.Ī more important thing to do is to have an educated conversation with your provider about your medical history, past birth experiences, your incision type, and plans for your family size.
Today, I will explain why I have such strong feelings about the VBAC calculator and what ACOG says about its use. If you have listened to our VBAC podcast at all, you know I have a strong opinion on the VBAC score provided by these calculators. Right off the bat, those considering VBA2C, VBA3C, or those with special scars are excluded. The VBAC calculator data only accounts for those with one Cesarean and a low transverse incision.
If you are preparing for a VBAC and your provider has never referred to your VBAC score or how likely you are to have a VBAC, consider yourself lucky! The VBAC success calculator uses statistics from 7,000 VBAC attempts in the United States to determine how likely YOU are to have a VBAC.
There is outdated evidence, updated evidence, and conflicting evidence surrounding its accuracy and use for those attempting a trial of labor after Cesarean ( TOLAC).Įven ACOG seems to contradict itself in its current VBAC guidelines. The VBAC calculator ACOG references in some of its bulletins and guidelines is a hot topic in the birth world.