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A caesarean section may be a choice for some women, but for others, they prefer a vaginal birth if possible. If they had a caesarean section previously, they may still want a vaginal birth with the next baby. Whilst everyone wants a safe and healthy outcome for mum and baby, it is also important to consider choice and control as part of the overall outcomes and experience. So, when you are thinking about a Vaginal Birth After Caesarean (VBAC) what sort of things should you take into consideration?
Why did you have a Caesarean?
The first thing to consider, is why the caesarean section was done. It may have been a planned procedure (for example for a breech baby, twins, low placenta) or it may have been performed in labour as baby was not coping well, you were unwell, labour was not progressing as expected. Caesarean sections very early in pregnancy (typically less than 28 weeks) may have involved a different type of incision into your uterus, whilst those performed in the second stage of labour occasionally have an incision too low in your uterus. All these factors come with different things to consider. Will it happen again? Are there specific risk factors? Are problems more likely if I aim for a VABC? For this reason, we would always advise you sit with a health professional to talk through what happened last time and how it impacts on a future pregnancy. Ideally, this would be with your previous birth notes. You can request a copy of your previous notes from the hospital who provided your care.
Risks of a VBAC
When you first talk about a VBAC, the work “risk” is often mentioned. Basically, this means the “chance” of something happening. With a VBAC, there are two main things that health professionals may worry about:
- The placenta can stick to the old scar and grow into it – this is called Placenta Accreta.
The risk (or chance) of this happening have been reported to be as high as 1:300 and as low as 1:2000 pregnancies. The condition is more common in women with a previous caesarean section or uterine surgery. The main problem with this condition is haemorrhage, which can occur during pregnancy or during labour. Average blood loss is between 2 litres and 7.8 litres. This can be fatal. For this reason, all women who have a low, anterior placenta who had a caesarean section previously, are advised to have a detailed scan in a specialist facility to look at the placenta, how it is attached and how it is growing. This may include MRI imaging.
- The old scar can rupture.
The chance of the scar rupturing is low. Some things make this more likely to happen, for example, if you are over 40yrs old, had a baby within the last 12 months, pregnancy is very overdue, baby is very large, or you have a high BMI. Induction or labour also increases the risk. If the scar does rupture, it can be life threatening for mum and baby.
Risk of scar rupture in simple terms:
Studies looking at scar rupture vary in their results and this is largely because the incidence is so low. In simplified terms, risks of scar rupture in planned VBAC deliveries:
Induction of labour – just over 1% (1.02%)
Augmentation of labour – under 1% (0.87%)
Spontaneous labour – 0.1%
Risk of uterine rupture when there is no scar on the uterus* – 0.02%
(*whether labour is spontaneous, induced or augmented)
For these reasons, women who do decide on a VBAC are normally advised to have their baby in hospital.
Place of birth
In some cases, the previous birth experience was a traumatic event and women just can’t face being in hospital again. For others, they truly believe that their best chance of birthing a baby vaginally and having a positive experience is to be at home. Home Birth After Caesarean (HBAC) means that some of the monitoring offered in hospital can’t be offered at home. It also means that if a problem does occur, emergency help if delayed. This needs to be balanced with the reduction in the need to be induced or have labour augmented, movement restrictions resulting in labour being longer, and being disturbed or cared for by unfamiliar people – which in themselves are risk factors.
A recent, large study looked at whether the mode of delivery and maternal and neonatal outcomes differed between planned home HBAC and hospital VBAC*. The study had 4741 cases. 88% planned a hospital VBAC and 12% planned a HBAC. The study found that even when the results were adjusted to take account of the specific risk factors which may increase or decreased VBAC rate, those women at home were still significantly more likely to birth vaginally compared to those in hospital.
The next question is about the safety of those results. Was that high vaginal birth rate associated with a higher number of problems for mum or baby? Well severe adverse outcomes were very low in both settings and because of that the researchers were unable to say if either location was safer or not. Basically, things didn’t go wrong often enough to see a meaningful difference.
The authors concluded that, “Home births for those eligible for VBACs and attended by registered midwives within an integrated health system were associated with higher vaginal birth rates compared with planned hospital VBACs. Severe adverse outcomes were relatively rare in both settings.” (Bayrampour et al 2021).
In other words, the birth was attended by a trained midwife who had access to hospital facilities if needed. If you decide to have a HBAC with an inexperienced midwife, or no midwife at all, the results and outcomes may be very different.
* Source: https://onlinelibrary.wiley.com/doi/abs/10.1111/birt.12539
Choosing your care provider
Having the right people with you is important in any labour, but for a VBAC it is crucial. It is important that antenatally you have time to review previous notes, talk through events, consider all “risks”, and explore all options. For this reason, we ask all HBAC clients to book as soon as possible and we prefer not to offer our smallest care packages. There just isn’t enough time to do everything properly if care starts very late in pregnancy. Maximising the chance of a healthy and positive outcome requires investment and time from you and your midwife, working together in partnership.
It is important that your care provider is an experienced home birth midwife if you are opting for a HBAC and want the best possible outcomes. You don’t want someone who is anxious and on edge for no specific reason. Likewise, you need someone who you have confidence in, who you trust and who is closely working with you and ensuring all is well.
Useful Resources on VBAC and HBAC
Bayrampour H, Lisonkova S, Tamana S et al (2021). Perinatal outcomes of planned home birth after cesarean and planned hospital vaginal birth after cesarean at term gestation in British Columbia, Canada: A retrospective population‐based cohort study. Online ahead of print. https://doi.org/10.1111/birt.12539
RCOG Birth After Previous Caesare4an Birth. Green Top Guideline No 45.
https://www.rcog.org.uk/media/kpkjwd5h/gtg_45.pdf
Home Birth After Caesarean: Dr Sara Wickham
https://www.sarawickham.com/research-updates/hbac/
RCOG Placenta Praevia and Placenta Accreta: Diagnosis and Management. Green Top Guideline 27a.
Private Midwives resource library
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