Vaginal birth after caesarean (VBAC): what the evidence says
If you have had a caesarean section and become pregnant again, you will at some point need to make a decision about how your next birth will happen. The two main options are a planned vaginal birth after caesarean (VBAC) or a planned repeat caesarean section, often called an elective repeat caesarean section (ERCS). Both are legitimate choices with their own benefits and risks, and neither is the right answer for every person. This article draws on NHS guidance and the Royal College of Obstetricians and Gynaecologists (RCOG) Green-top Guideline 45 to help you understand the evidence so you can have a more informed conversation with your midwife and obstetric team.
What VBAC means in practice
VBAC simply means planning to give birth vaginally after having previously delivered by caesarean. It is not a guarantee of a vaginal birth: it is an intention and a plan, made in partnership with your clinical team, with appropriate facilities and monitoring in place. The alternative, ERCS, is a planned operation scheduled for around 39 weeks of pregnancy. Both pathways require active discussion, and UK guidance encourages maternity teams to support women in accessing balanced information about each option from early in the third trimester.
It is worth understanding that the decision is not necessarily final until labour begins. Women who plan a VBAC may still need or choose to have a caesarean during labour for clinical reasons, and some women who initially consider ERCS change their minds as they learn more about VBAC outcomes. The important thing is that the conversation happens early enough to allow time for reflection.
Who is a good candidate for VBAC?
VBAC is considered appropriate for many women, but it is best suited to those who meet certain clinical criteria. According to RCOG guidance, the characteristics associated with a reasonable VBAC candidate include having had one previous lower segment caesarean section (the most common type, involving a horizontal incision low on the uterus), no history of uterine rupture in a previous birth, a single uncomplicated pregnancy at term, and access to a consultant-led maternity unit that can provide continuous fetal monitoring and immediate access to an operating theatre if needed.
These criteria exist because the setting and level of support available during labour have a direct bearing on safety. VBAC is not typically recommended in units that cannot provide round-the-clock obstetric and anaesthetic cover, because the main risk associated with it (uterine rupture, discussed below) requires very fast action if it occurs.
Some factors make a successful VBAC more likely. According to RCOG, women who have previously had a vaginal birth, including a previous VBAC, have higher success rates. Labour that begins spontaneously, rather than being induced, is also associated with better outcomes. If the previous caesarean was performed for a reason that is not present in the current pregnancy, such as the baby being in a breech position, that is another positive indicator. By contrast, if the original caesarean was for failure to progress in labour, the chance of a successful vaginal birth may be somewhat lower, though many women in this category still go on to have successful VBACs.
How often does planned VBAC succeed?
The RCOG reports that around 72 to 75% of planned VBACs in the UK result in a successful vaginal birth. That figure covers planned VBACs as a whole: individual likelihood varies depending on the factors described above. Women who have previously given birth vaginally, for instance, tend to have success rates towards the higher end of that range. The remaining 25 to 28% of planned VBACs end in an unplanned caesarean section during labour, most commonly because labour does not progress as expected or concerns arise about the baby's wellbeing on the fetal monitor.
It is reasonable to ask your team what they estimate your personal chance of a successful VBAC to be, given your specific history. Most consultant-led units now have structured VBAC antenatal counselling appointments to work through exactly this kind of individualised assessment.
The main risk: uterine rupture
The risk that distinguishes VBAC from other births is uterine rupture, which means the scar from the previous caesarean gives way during labour. According to the NHS, the risk of this happening is approximately 0.5%, which is around 1 in 200 planned VBACs. This is a rare event, but it is a serious one. When uterine rupture occurs, the baby must be delivered immediately by emergency caesarean, and the mother requires prompt surgical repair.
The key point here is the phrase "properly equipped unit." In a consultant-led unit with continuous fetal monitoring and an operating theatre immediately available, uterine rupture can usually be managed successfully. The fetal heart rate pattern on the CTG monitor often gives early warning that something is wrong, allowing the team to act quickly. This is why VBAC outside of a well-resourced hospital setting is not recommended, and why continuous CTG monitoring throughout VBAC labour is standard practice in the UK.
It is also worth keeping this figure in context. A 0.5% risk means that, in 199 out of 200 planned VBACs, uterine rupture does not occur. Understanding the absolute risk, rather than simply hearing that uterine rupture is "possible," helps most women engage more clearly with the decision.
The risks of planned repeat caesarean
ERCS is not without its own risks, and these deserve equal consideration in the decision. A caesarean is major abdominal surgery, and the recovery is typically longer than after a straightforward vaginal birth. More significantly for women who plan further pregnancies, each caesarean increases the complexity and risk of subsequent ones. With each additional caesarean scar, the likelihood of placenta praevia (where the placenta lies low and covers the cervix) and placenta accreta spectrum (where the placenta grows too deeply into the uterine wall) rises. These are serious complications that require specialist management and can affect future fertility. Women who know they want several children often factor this into their thinking about whether to attempt VBAC.
Short-term risks of ERCS include the usual surgical risks of bleeding, infection and anaesthetic complications, as well as a small risk of injury to the bladder or other nearby structures. Babies born by caesarean before labour has begun also have a slightly higher rate of breathing difficulties in the newborn period compared with babies born vaginally, because the process of labour itself helps prepare the baby's lungs for breathing outside the womb.
Monitoring during VBAC labour
If you plan a VBAC, continuous electronic fetal monitoring (CTG) throughout labour is recommended in UK guidelines. This means being attached to a monitor that records your baby's heart rate pattern continuously, rather than intermittent checks with a handheld device. The CTG allows the team to spot signs of fetal distress early and to look for patterns on the trace that might suggest the uterine scar is under stress.
Continuous monitoring does limit mobility to some degree, though many units now offer wireless monitors that allow more movement than traditional equipment. It is worth asking your unit what is available. The recommendation for continuous CTG applies specifically to VBAC because of the need to respond quickly if uterine rupture begins. Women who choose ERCS, or who are having a straightforward vaginal birth without a uterine scar, follow different monitoring guidelines.
An epidural for pain relief is not contraindicated in VBAC. Some women prefer to avoid one to maintain maximum mobility or to be able to feel the sensations that might indicate something is wrong, but this is a personal choice rather than a clinical requirement. Your team should support whichever approach to pain relief you decide on.
Talking to your team
UK maternity guidance recommends that women with a previous caesarean are offered a dedicated antenatal appointment to discuss their birth options. This is your opportunity to ask about your individual success rate estimate, the facilities at your unit, induction policies for VBAC (induction increases the risk of uterine rupture somewhat, so many units approach it cautiously), and anything else that is relevant to your situation. If you feel you have not had enough time or information to make this decision comfortably, ask for a longer appointment or a referral to a senior obstetrician.
The decision belongs to you. Both VBAC and ERCS are reasonable, supported choices in the UK. A good maternity team will present balanced information and support you in whichever direction feels right for you and your family, without pressure in either direction.
Frequently asked questions
What is VBAC?
VBAC stands for vaginal birth after caesarean. It means planning to give birth vaginally in a pregnancy that follows a previous caesarean section. The alternative is a planned repeat caesarean section, sometimes called an elective repeat caesarean section (ERCS). Both are valid options and the decision is made with your consultant or specialist midwife based on your individual history.
What is the success rate for VBAC?
According to RCOG data, around 72 to 75% of planned VBACs in the UK result in a successful vaginal birth. Your personal chances may be higher if you have had a vaginal birth before, if labour starts spontaneously, and if the reason for your previous caesarean is not present in this pregnancy.
What is the risk of uterine rupture with VBAC?
The risk of uterine rupture in a planned VBAC is approximately 0.5%, or around 1 in 200, according to NHS and RCOG data. This is a serious obstetric emergency, but it is manageable when it occurs in a consultant-led unit with continuous fetal monitoring and immediate access to theatre. The risk is higher if labour is induced with prostaglandins.
Is a planned repeat caesarean section safer than VBAC?
A planned repeat caesarean section (ERCS) avoids the small risk of uterine rupture, but it carries its own risks as major abdominal surgery. These include a longer recovery, higher risk of blood transfusion compared with vaginal birth, and an increased risk of placenta problems in any future pregnancies. Neither option is without risk, which is why the decision is made individually with your medical team.
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