If you are considering a vaginal birth after cesarean (VBAC) here in Ventura County, chances are you have already typed some version of "VBAC success rate" into a search bar. Maybe you found a calculator, entered your details, and stared at a percentage that felt either wonderfully reassuring or quietly discouraging. Before you let that number settle into your heart as a verdict, take a breath. The story behind VBAC success rates is far more hopeful, and far more nuanced, than any single figure can capture.

At The Midwife & More, Christy Cannon, CNM, WHNP-BC helps parents across Thousand Oaks, Westlake Village, Agoura Hills, Simi Valley, and the surrounding communities read those numbers the way clinicians actually do: as a starting point for a conversation, not the final word on what your body can do. As the first certified nurse-midwife to offer holistic birth at Los Robles Hospital in Thousand Oaks, Christy pairs a gentle, midwifery-led approach with a full hospital safety net and an on-call collaborating OB, Dr. Thomas Cachur. That combination matters when you are weighing the odds, because good numbers are only useful when they sit inside good care.

The Big Picture: A 60 to 80 Percent Success Story

Let's start with the headline that too many people miss. For those who attempt a trial of labor after cesarean (TOLAC), the overall success rate lands somewhere between roughly 60 and 80 percent. The American College of Obstetricians and Gynecologists (ACOG) describes VBAC as a safe and reasonable option for most people with one prior low-transverse cesarean. Optimal candidates, meaning those with the most favorable combination of factors, are generally predicted to succeed more than 60 percent of the time, and many climb well above that.

Sit with that for a moment. A majority of people who plan a VBAC and go into labor end up birthing their baby vaginally. That is not a long shot. That is a well-supported, common outcome that happens every day in hospitals like Los Robles.

Did You Know? Obstetrics is the branch of medicine focused on pregnancy, birth, and the weeks that follow. Decades of obstetric research are what give us the success-rate estimates and prediction tools used to counsel families considering a trial of labor.

What Actually Drives the Numbers Up or Down

VBAC success is not random. Researchers have studied thousands of births to understand which factors nudge your personal likelihood higher or lower. Here is what carries the most weight.

Prior Vaginal Birth or Prior VBAC: The Biggest Boosters

Nothing raises predicted success quite like a history of vaginal birth. If you have delivered vaginally before, whether before your cesarean or after it, your chances of a successful VBAC rise substantially. The effect is even stronger for those with a prior VBAC specifically.

Consider the difference in the numbers. For people attempting VBAC with no prior vaginal delivery, success runs around 73 percent, already a strong figure. Add one or more prior VBACs and that figure jumps to roughly 92 to 97 percent. Your body has, in a very real sense, already proven the pathway.

One mom in the Conejo Valley put it this way after her second birth: she had delivered her first baby vaginally, then needed a cesarean with her second for a breech position. Going into her third pregnancy, she said that memory of her first birth was "the thing I held onto every time doubt crept in." Her prior vaginal birth was not just an emotional anchor. It was one of the strongest statistical predictors in her favor.

Spontaneous Labor Versus Induction

How labor begins matters too. Spontaneous labor, where your body starts the process on its own, is associated with higher VBAC success than induced labor. Induction can still absolutely lead to a successful VBAC, and it is sometimes medically necessary, but on average the odds are a bit more favorable when labor unfolds naturally. This is one of many reasons a patient, watchful approach to timing, the kind Christy is known for, can serve VBAC families well.

The Reason for Your First Cesarean

The indication for your prior cesarean shapes your outlook. If your first cesarean happened for a reason unlikely to repeat, such as a breech baby, fetal distress, or a placenta issue, your VBAC odds are generally better. If the cesarean followed a long labor that stalled, sometimes labeled "failure to progress" or arrest of dilation, predicted success may be somewhat lower, though many people in this group still succeed beautifully. A non-recurring reason is a quiet point in your favor.

BMI and Age: Modest, Not Decisive

Higher body mass index (BMI) and older maternal age are each associated with slightly lower predicted success. The key word is slightly. These are modest factors, not deal-breakers. Plenty of people over 35 and plenty of people across the BMI spectrum have wonderful VBACs. When a calculator dings your score a few points for age or BMI, it is fine-tuning an estimate, not closing a door.

How VBAC Calculators Actually Work

The most widely referenced tool is the calculator developed through the NICHD Maternal-Fetal Medicine Units (MFMU) Network. It was built by following a large group of people attempting VBAC and identifying which characteristics, gathered at the first prenatal visit, best predicted a vaginal outcome.

The original model draws on a handful of inputs:

  • Maternal age
  • Body mass index (BMI)
  • Prior vaginal delivery
  • Prior successful VBAC
  • Indication for the prior cesarean

An important and welcome update: a newer version of the calculator removed race and ethnicity as inputs, because including them was found to unfairly and inaccurately lower predicted scores for some groups. The revised model added chronic hypertension as a factor instead. If you used an older calculator years ago, the modern version may give you a different, fairer picture.

Here is the crucial part about accuracy. These calculators perform best when they predict a high likelihood of success. When the predicted score is 60 percent or higher, the estimate tends to be quite reliable. When the predicted score dips below 40 percent, the calculator becomes less dependable, and it may underestimate what is truly possible for you. That asymmetry is exactly why a moderate or even lower-looking number should never be read as a sentence.

Why a Number Is a Conversation Starter, Not a Verdict

Perhaps the single most important thing to understand is what a calculator does and does not tell you. It estimates the likelihood of a vaginal birth. It does not measure the safety of attempting one, and a lower score by itself does not predict that anything harmful will happen. Safety is a separate conversation, one that depends on your uterine scar, your health history, and the care setting around you.

Calculators also cannot see the whole of you. They do not know your determination, the quality of your labor support, whether your provider is patient with the natural rhythm of labor, or a hundred small clinical details that unfold in real time. They are a snapshot built from averages, and you are not an average.

We think of one client who came in deflated after an online tool spit out a number in the low 50s. She had nearly talked herself out of even trying. After a longer conversation about her history, her strong motivation, and a supportive plan for spontaneous labor, she went on to have a smooth, empowering VBAC. Her "moderate" number had told only a sliver of her story. A predicted score in that middle range still often means a genuinely good chance, and even numbers that look modest on paper leave enormous room for a joyful outcome.

This is where personalized counseling earns its keep. A calculator can open the door. A knowledgeable midwife walks you through it. During a free birth consult with The Midwife & More, Christy can help you interpret your factors honestly, neither sugarcoating nor catastrophizing, so you can make a decision that feels grounded and truly yours.

Explore Your Own Factors

Curious where you might land? The interactive "Am I a VBAC Candidate?" tool on this site is a gentle, private way to explore the factors we have discussed and see how they fit together for you. Think of it, like the medical calculators, as a place to begin the conversation rather than end it. Whatever it shows, the next best step is a real discussion with a provider who knows VBAC well.

Frequently Asked Questions

Should I be discouraged if my VBAC calculator score is low?

Not at all. Calculators are least reliable at the lower end and often underestimate real-world success. A lower score is a reason to have a thoughtful conversation with your provider, not a reason to give up. Many people with modest predicted scores go on to have successful VBACs.

Does having one previous vaginal birth really make that much difference?

Yes. A prior vaginal delivery, and especially a prior VBAC, is one of the strongest predictors of success. Success rates for those with a prior VBAC can reach the low-to-mid 90s. Your body having done it before genuinely shifts the odds.

Is a VBAC calculator the same as being cleared for a VBAC?

No. A calculator estimates the likelihood of a vaginal birth. It does not assess whether attempting a VBAC is safe for your specific situation. That safety review, including the type of uterine incision and your health history, is a separate discussion with your midwife or physician.

Can I still have a VBAC if my labor needs to be induced?

Often yes. Spontaneous labor carries somewhat higher success rates, but induction can still lead to a successful VBAC and is sometimes the right medical choice. Your provider can talk you through the safest approach for you.

A Personal, Local Path Forward

Numbers are useful, but they are only part of the picture. The rest is the care around you: a midwife who listens, a hospital safety net at Los Robles, and a collaborating OB ready if needed. The Midwife & More offers concierge, personalized support to families across Ventura County and western Los Angeles, including Thousand Oaks, Westlake Village, Agoura Hills, Simi Valley, Newbury Park, Moorpark, Camarillo, Oak Park, and Calabasas. As a PPO out-of-network practice, care may be reimbursable through your plan.

To talk through your own factors with someone who reads these numbers every day, reach out for a free birth consult:

The Midwife & More — Christy Cannon, CNM, WHNP-BC 5115 Clareton Drive, Suite 100, Agoura Hills, CA 91301 Phone: (805) 558-5145

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Medical Disclaimer

This article is for general educational purposes only and is not a substitute for individualized medical advice. VBAC success rates and calculator results are estimates based on population data and cannot predict your specific outcome. Always consult a qualified healthcare provider about your personal circumstances, including your health history and the type of your prior uterine incision, before making decisions about your birth.