Nurse Giving Nitroud Oxide Mask to Pregnant WomanSo you’re planning your VBAC and feeling pretty confident! Then someone, maybe your care provider while discussing the pros and cons of VBAC and repeat Caesarean, happens to mention that VBAC mums have a higher chance of experiencing a significant perineal tear or having an episiotomy or instrumental birth.

So is this true? In short, the evidence tells us yes. In one large Irish study, VBAC mums had a 9% higher chance of instrumental birth and an 8% increased risk of episiotomy compared to mums who had never given birth. VBAC mums had a 5% chance of a significant perineal tear while first time mums had a 3.6% chance.

But there’s more to these figures that meets the eye. Why would this be the case? These mums have given birth before and many have laboured before having their caesarean birth.



VBAC mums in labour are usually considered ‘high risk’ because of the chance of uterine rupture. This is a relatively rare (less than 1% chance) complication but can have serious implications for both mother and baby when it does occur. Because of this, mothers attempting a VBAC are subject to more monitoring and often quicker intervention by their healthcare providers. In the 99% of cases where uterine rupture doesn’t occur, this extra vigilance is a double-edged sword for women.


Why? Well, one of the problems is the way women are monitored in labour. CTG or cardiotocography, is a way of monitoring a baby’s heart rate and a mother’s contractions. It is sometimes also called EFM, or electronic foetal monitoring. We know that EFM has a high rate of ‘false positives’, making it look like your baby isn’t doing well, when in fact he may be fine.

There is also plenty of sciencific evidence telling us that EFM (whether or not you’re planning a VBAC) increases your chances of instrumental birth (forceps or vacuum) and also your chances of caesarean birth very significantly.

EFM can also reduce a woman’s ability to stay mobile during her labour, and while this may not sound like a big deal, the research points out that babies whose mothers adopt upright positions in labour have a 54% decreased chance of heart rate abnormalities during the labour. Not only that, but upright positions in labour are associated with fewer perineal tears and a 21% reduction in a mother’s chance of episiotomy.

Episiotomy is a surgical cut made in the perineum to speed up the birth of the baby, help prevent more severe perineal damage or to allow the use of forceps or vacuum during the birth. However, studies have found that episiotomy doesn’t seem to change the incidence or severity of perineal tears and can in fact, sometimes contribute to more significant tears.


Ok, so if you’re a mum attempting VBAC, you now know that your risk of various birth interventions is increased. You also are aware of some of the reasons why.

Now you need to start thinking about how to start ‘stacking the odds’ in your favour for a successful VBAC. I’ve included links below to some articles that may be useful and interesting for you in your journey. And you can read more in my next post ‘Stacking the Odds for Your Successful VBAC‘.


Some Useful Links

A Midwife’s perspective on VBAC:

VBAC: making a mountain out of a molehill

Evidence on the use of CTG:


Birthing in Upright Positions:

Comfortable Upright Birth have a huge list of excellent resources.

Also, attending an independent VBAC class is invaluable when planning a VBAC (details on