VBAC: The Facts, the Fears and Your Choice

Written by Shannon Pike

If you've had a caesarean and you're pregnant again, there's a good chance someone has already told you what you can and can't do next time. Maybe you've heard 'once a caesarean, always a caesarean'. However, that notion is out of date and not a true representation for the majority of cases.

Let's look at what the evidence actually says, including the scary bits, because you deserve the full picture and not just the headlines.

First, what is VBAC?

VBAC stands for vaginal birth after caesarean. It includes births assisted with forceps or ventouse, and it's one of two options the NHS should offer you after a previous caesarean.

The other is a planned repeat caesarean. The RCOG patient information is clear that each option has risks and benefits and that, ultimately, the decision is yours.

The RCOG's Green-top Guideline 45 says there is consensus between NICE, the RCOG and the American College of Obstetricians and Gynaecologists that planned VBAC is a clinically safe choice for most women with one previous lower segment caesarean. NICE's quality standard goes further: if you choose to plan a vaginal birth after a caesarean, you should be fully supported in that choice.

Why the system worries

Let's be honest about this, because pretending the worry isn't there doesn't help anyone. It comes down to one thing: uterine rupture, where the scar from your previous caesarean separates or tears during labour.

The RCOG says this can happen in up to 1 in 200 women planning VBAC (about 0.5%), compared with fewer than 1 in 4,000 with a planned repeat caesarean.

A large systematic review for the US Agency for Healthcare Research and Quality found a similar gap: 4.7 per 1,000 in a trial of labour, versus 0.3 per 1,000 with a planned repeat caesarean.

NICE tells maternity teams to inform you that the risk of uterine rupture is higher with a planned vaginal birth.

What makes it serious is not how often it happens, but what happens when it does:

  • It can cause heavy, life-threatening bleeding, and up to 1 in 3 women who have a rupture may need an emergency hysterectomy (RCOG).

  • Serious outcomes for babies, including brain injury or death around the time of birth, are slightly higher with planned VBAC than with a planned caesarean, affecting around an extra 10 in 10,000 babies (RCOG).

  • It can sometimes happen without warning, and the AHRQ review found that no models have been able to accurately predict who will rupture.

That unpredictability is the heart of the system's caution. When something is rare but sudden and severe, and you can't tell in advance who it will affect, services build safety nets around everyone.

That's why you'll be advised to give birth in hospital with continuous monitoring (more on that below).

The other worry is the unplanned caesarean. Around 1 in 4 women planning VBAC end up with an emergency caesarean, and the RCOG notes that an emergency caesarean carries more risks than a planned one.

Putting that risk in context

The risk of rupture is real, but it's one risk among many, and a repeat caesarean has its own list.

The RCOG says that the risk of your baby dying because of a planned VBAC is very low and is about the same as if you were giving birth vaginally for the first time, around 4 in 10,000 births.

On maternal safety, the RCOG gives the risk of a woman dying during or soon after birth as very low either way, with a planned vaginal birth at 4 in 100,000 compared with 25 in 100,000 for a planned caesarean.

On the other side of the scale, the RCOG lists these for planned repeat caesarean birth:

  • Infection of the wound or uterus is common, affecting 2 to 7 in 100 women.

  • Recovery usually takes around 6 weeks, and no driving for up to 6 weeks is not unusual.

  • More scar tissue builds up with each caesarean, which raises the chance of the placenta growing abnormally into the scar in future pregnancies (around 1 in 1,000 after a previous caesarean).

  • All serious risks increase with every caesarean you have, so it matters if you're hoping for more babies.

And for VBAC, the RCOG also notes a slightly higher chance of a blood transfusion (around 4 in 1,000 versus 3 in 1,000 with a planned repeat caesarean), and a chance of assisted birth or a tear involving the anal sphincter.

NICE adds that for women who have had up to 4 previous caesareans, the risk of fever, bladder injury and surgical injury does not vary with the planned mode of birth.

The point isn't that one option is safe and the other is dangerous. Both are generally safe, and the risks are just different.

The part that doesn't make the headlines: Most VBAC’S are successful

Here is the bit to remember…

If you have had one caesarean and your labour starts naturally, three out of four women who choose VBAC go on to give birth vaginally. The RCOG's Green-top Guideline puts the success rate of planned VBAC at 72 to 75%. In the US, ACOG reports a similar range of 60 to 80% for a trial of labour after caesarean.

It gets better if you have already had a vaginal birth, before or after your caesarean: about 8 to 9 out of 10 women go on to have another vaginal birth.

NICE also says maternity teams should tell women with a previous vaginal birth that they are more likely to have a vaginal birth than those who haven't.

So the headline is this: yes, you are at a higher risk of one rare complication, and yes, most people who plan a VBAC will go on to have a vaginal birth. Both of those are true at the same time.

What influences the chances

Your chances depend on you and on how labour starts.

The RCOG says you are more likely to have a vaginal birth if one of the following is true:

  • You have had a vaginal birth previously

  • Your labour starts naturally (without induction)

  • Your BMI is under 30 at your first antenatal check

ACOG's bulletin also lists the following factors that may reduce the chances of a successful VBAC:

  • Advanced maternal age,

  • High birth weight,

  • Going past 40 weeks gestation

  • Pre-eclampsia

Induction deserves a special mention. The RCOG says that if labour is induced there is a higher chance of needing an emergency caesarean, and the risk of uterine rupture can be two to three times higher, depending on how labour is started.

If labour doesn't start on its own by 41 weeks, you'll be offered a conversation about your options: keep waiting, induction, or a planned caesarean. None of them is a wrong answer, but it's good to know that conversation is coming.

What to expect if you plan a VBAC

NICE says women planning a vaginal birth after caesarean should be offered electronic fetal monitoring and care in a unit with immediate access to caesarean birth and on-site blood transfusion.

The RCOG adds that once you're having regular contractions you'll be offered continuous monitoring of your baby's heartbeat, because changes in the heart rate pattern can be an early sign of problems with the scar.

You'll also be advised to have a blood sample taken and a cannula put in. This can make it harder to move around or choose some positions, so it's worth talking through your options with your midwife in advance. Epidurals are an option.

Signs that would prompt an emergency caesarean include unexpected vaginal bleeding or changes in your baby's heart rate pattern.

When VBAC isn't advised

The RCOG says VBAC is not advisable if one or more of the following are true:

  • You have had 3 or more previous Caesareans

  • If your uterus has ruptured in a previous labour,

  • If your previous caesarean was a 'classical' one (the incision involved the upper part of the uterus), or if you have other pregnancy complications that need a planned caesarean.

For anything outside the usual picture, such as more than one previous caesarean, you should be advised on the benefits and risks of your options in your individual situation.

It's your birth, and either choice is valid

I'm a doula, so I'm biased in one direction: towards you being informed and supported, whatever you choose.

A planned repeat caesarean is a completely legitimate choice, and so is VBAC. What matters is that you're choosing with the real numbers in front of you, and not out of fear or because nobody told you there was an option.

The RCOG suggests asking three questions at your appointments:

  1. What are my options?

  2. What are the pros and cons of each option for me?

  3. How do I get support to help me make a decision that is right for me?

Ask your midwife whether your hospital offers a birth options clinic or a specialist midwife, and if not, ask for extra time with your midwife or consultant to talk it through.

If your last birth left you with difficult feelings, that’s a valid thing to bring up too.

“I'm a doula, not a clinician, and this post is general information and not medical advice. Your own history matters, so please talk through your individual situation with your midwife or obstetrician.”

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Shannon Pike
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