Important: This is intended as general information only. It may not apply to your specific situation. It is not a substitute for medical advice. If you have a question or concern, please raise it with me at your next appointment or contact me sooner if it's urgent.
Vaginal Birth After Caesarean Section
A vaginal birth after a caesarean section (VBAC) is an option for women who have had one previous caesarean. After two previous caesarean sections, the risks of a labour and vaginal delivery increase. Most experts recommend against a VBAC for women who have had 2 previous caesareans. However, after one caesarean section, there are pros and cons of both a VBAC and a repeat elective caesarean section. In the absence of any clear medical reason why you should have one over the other, you can decide which option suits you best. If you have had a previous caesarean section and are considering a VBAC, we will discuss the pros and cons of each approach throughout your pregnancy.
About 60%, or almost 2 out of 3, of the women who attempt a VBAC will be successful. These are pretty good odds but it does, of course, mean than 40%, or just over 1 in 3, women will require a caesarean in labour – either because the labour does not progress, the baby becomes distressed or there is some other complication.
Risks of VBAC
The primary risk of a VBAC is that the scar on uterus may separate or rupture. This happens to approximately 1 in 200 (0.5%) of the women who attempt a VBAC. Obviously, this is a major complication. However, we manage these labours slightly differently to a ‘regular’ labour with the aim that we can intervene quickly if there are any signs of trouble. This means that the overall risk of a bad outcome for the baby is low – approximately 1 per 1000 VBACs. You might imagine that, in the event that the uterine scar was separating, you might feel pain or experience bleeding. In fact, the earliest sign of problem with the scar is usually a change in the baby’s heart rate. For this reason, women having a VBAC need to have continuous monitoring of the baby’s heart rate performed during labour. Depending on the degree of damage to a ruptured uterus, it may not be possible to repair the uterus and a hysterectomy may be necessary.
Advantages of a VBAC
The primary advantage of a VBAC is the faster, less painful recovery associated with a vaginal delivery compared with a caesarean. This particularly motivates women who have a toddler at home to look after as well as their new baby. Having said that, many women report that their recovery from a caesarean second time is much easier – perhaps because they know what to expect and how to manage it.
Some women feel that a vaginal delivery is, in itself, an experience worth having. Only you can decide whether this is important to you.
Risks of a repeat elective caesarean
There are small risks of major and minor complications associated with all surgery – see the Delivery by Caesarean Section info sheet for more about this. While this is, by and large, a very safe operation, consideration of the risks should certainly weigh into your decision. Remember, of course, that all vaginal deliveries (even without uterine rupture) also carry risks.
The main disadvantage of a caesarean, as alluded to above, is the recovery. Second caesareans are often easier in this regard. For one thing, you know what to expect and have had some experience with the benefits of managing pain proactively. Many first caesareans are emergencies performed in labour and therefore the recovery is from the labour as well as the surgery. Another big difference is that you also wont have the stress of being a first time parent with everything that that entails.
Advantages of a repeat elective caesarean
A repeat elective caesarean eliminates the risks associated with labour – particularly the risk to the baby of a ruptured uterus. The ‘scheduled’ nature may also be of benefit to some families. Some women are uncomfortable with the fact that attempting a VBAC may not be successful – they go through the labour and end up needing a caesarean anyway.
A word about risk
Everyone interprets risks differently and people prioritise advantages and disadvantages differently. In the absence of other complications, there is no right answer here. Overall, most experts would agree that a VBAC is marginally safer for the mother and a repeat elective caesarean is safer for the baby. This actually makes the decision a bit more complicated as, either way, one person takes the risks and the other reaps the benefits.
Who is eligible for a VBAC
To be consider for a VBAC you must
- Have a singleton fetus
- Have a cephalic (head first) fetus
- Have no other major complications in the pregnancy
- Have had only one previous caesarean section
Go into labour spontaneously – there are a couple of shades of grey here, but our options for inducing labour are limited for women with a scar on their uterus
It may happen that something arises during the pregnancy that makes a VBAC a bad idea. For example, a low placenta or a breech baby. For this reason, we will start discussing your plans early in the pregnancy but we generally don’t make a decision until later in the pregnancy.
One thing to think about is the reason for your first caesarean and whether it is likely to recur. For example, if you had an obstructed labour with a small baby first time around, and this baby seems bigger, it’s unlikely to be successful. If, on the other hand, you labored well, got to 8cm dilatation and needed a caesarean for fetal distress, you’re much more likely to have a successful VBAC.
Differences between a VBAC and a ‘regular’ labour
There are two main differences between a labour in women with a uterine scar and without.
The first is that the baby’s heart rate will be monitored continuously throughout the labour. The machines we use to do this these days are pretty good – some are even wireless – so that shouldn’t restrict your movement or position in labour too much.
The second is that an IV cannula (drip) will be placed in your hand at the beginning of the labour and blood will be taken for a cross match. The cannula does not need to be connected to an IV line so shouldn’t restrict your movements in labour. This is done so that, in the event of an emergency, we will have already established intravenous access and have cross-matched blood available.
As per labour in women without a uterine scar, you can chose how much or how little pain relief you have. There is no reason why you can’t have the full range of pain relief, including an epidural, in a VBAC if you want to.
