Episode 9: Birth following caesarean section
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Episode 9 Content and Overview
In episode 9 of the Pregnancy and Childbirth podcast, Dr Greg Jenkins, obstetrician and gynaecologist, talks about birth following caesarean section.
Listen to this episode to learn about:
Why birth following caesarean section is an issue
The principles of making important decisions around medical care or shared decision making
The risks versus benefits and the framework that sits around that decision making for each individual woman
Special circumstances that arise on occasions
Care during labour if you are pursuing a vaginal birth after caesarean
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Transcription
00:00:00
Hi, I'm Greg Jenkins and welcome to my pregnancy podcast. Today we're going to talk about birth following caesarean section. This is commonly known as VBAC or NBAC. NBAC stands for next birth after caesarean and VBAC stands for vaginal birth after caesarean.
00:00:21
I'm going to cover a few different areas. The first thing we'll talk about is why is this an issue? The second thing we'll talk about is the principles of making important decisions around medical care or shared decision making. Next, we’ll cover the risks versus benefits and the framework that sits around that decision making for each individual woman. We’ll then cover some of the special circumstances that arise on occasions and then finally talk about care during labour if you were pursuing a vaginal birth after caesarean. So let's hop into it.
00:00:57
The first thing is why is this an issue? Well, if you've had a caesarean before, then you're faced with the choice as to whether you want to have a caesarean again, or whether you'd like to attempt a vaginal birth. Now this is an important decision because unlike your first pregnancy or the pregnancy which ended up with a caesarean, you now have a scar on your uterus and that poses some particular concerns around things that might happen during labour.
00:01:26
For some women this decision making is very clear. Some women come to pregnancy with a very clear idea of how they would like to approach the process of birth for their next pregnancy. But for many women this is a challenging decision which is made across the course of their pregnancy.
00:01:46
Let's talk about shared decision making to begin with. This is something that not only applies to decisions around caesarean section, but applies to most significant decisions in pregnancy and in fact across medical care generally.
00:02:01
So there's an acronym called SHARE which I think outlines very nicely the process of shared decision making and I think it helps both sides, both the medical practitioner or the health care provider and the patient, or in this case the pregnant woman, in understanding the framework that we work through in making this decision.
00:02:24
So, I would see my role very much as not telling you what to do but participating in a decision-making process with you.
00:02:34
So the first step, the S in SHARE, is about seeking your participation. So how we agreeable, that this is the process that we're going to work through together.
00:02:44
The second thing is helping to provide you with the information that you need to help guide your decision making and ensuring as far as possible that that's accurate and reliable information that's pertinent to your particular circumstance.
00:03:00
The A in SHARE is about assessing your values and preferences and bringing the information that we have into line with your preferences and values so that we can move towards making a decision.
00:03:15
The R is to reach an outcome. So to reach a decision about what you would prefer to do. And the E at the end is my evaluation of your decision. Evaluation is mostly going to mean that we reflect on the process that we've gone through and we feel satisfied that we've achieved an outcome that's being respectful of your personal autonomy to make an informed decision about the aspects of care that intimately affect you and your pregnancy and your baby.
00:03:50
However, there might be occasions where we don't come to complete agreement, but nevertheless I will still respect your choice to make an informed decision about your care.
00:04:03
The other useful thing to mention is that over the course of pregnancy, this is a conversation which happens rather than being a specific decision point. Meaning that we have time to think over these issues to digest them to see how pregnancy progresses and see how the progress of pregnancy sometimes influences the decisions which are arrived at at the end of pregnancy, which might be a little bit different to the decisions which could have been right at the beginning of pregnancy.
00:04:35
With all that out of the way, let's talk about how we make a decision. There are three things that I see as being major influences over the decision to attempt a vaginal birth, or to choose for a repeat planned caesarean.
00:04:53
The first is the likelihood of success, so is this attempt at a vaginal birth likely to be successful, and if so, how likely?
00:05:03
The second is what maybe the risks associated with attempting a vaginal birth after a caesarean in your particular circumstance. And the third is to acknowledge the framework with which you make those decisions. So, what are the things that are really important for you? What are your main priorities.
00:05:26
When it comes to assessing success or the likelihood of success in attempting a vaginal birth, there are characteristics about your past pregnancy histories that are very important.
00:05:40
So, for example, if you've had a successful previous vaginal birth already, whether that was prior to your past caesarian or following your past caesarian that increases your success rate quite substantial.
00:05:54
The other thing will be the circumstances around your caesarean. So why did you have a caesarean? So we know that for women who had a caesarean for what we call a nonrecurring indication, meaning something that was particular to that particular pregnancy, the likelihood of success for vaginal birth in a subsequent pregnancy is higher. So one of the examples around this would be a caesarean that was done for a breech presentation, so a baby that was coming bottom first. If your next baby is not breech, then there's quite a high likelihood that if you attempt to vaginal birth, you'll be successful.
00:06:34
There are other reasons for a caesarean. The most common reasons for a caesarean being performed during labour would be lack of making adequate progress during the course of labour or the baby showing signs of compromise in labour.
00:06:48
Now, if your previous caesarian was for a lack of progress in that the baby appeared to get stuck and was unable to fit through, then the likelihood of success for a subsequent vaginal birth is a little bit lower than for some of what are called nonrecurring indications.
00:07:07
There's also some personal characteristics around the mother. So we know that for women who have a higher BMI or a higher weight are the likelihood of success is it is a little bit lower.
00:07:20
It can also be a bit lower if you've had some other pregnancy complications, and if you're having a large baby. So, for example, a baby estimated to be greater than 4 kilograms, the success rate is likely to be lower.
00:07:35
In order to assist with these calculations, there are online VBAC success calculator. And if you Google VBAC success calculator, you'll come across some algorithms for which you can enter a number of your characteristics and they will give you some estimate of success.
00:07:55
Bearing in mind, these are just estimates and there may be things that are particular to you or to your pregnancy that you're a pregnancy care provider could guide you on a little bit more specifically than an online calculator will be able to. Nevertheless, they do provide some really helpful ballpark information.
00:08:18
So what about the risks of having a VBAC? There's a lot of focus around risk of VBAC, so this is something we need to focus our attention on. If you're a pregnant woman who's making a decision to undergo VBAC it, it is important that you are aware of the potential risks.
00:08:37
So what are the risks? So having had previous caesarean you know how to scale on the lower part of your uterus. This does not usually present a problem during the course of pregnancy, however, during labour when your uterus contracts, you generate very large pressures inside the uterus and the scar on leaders from your previous area is a potential weak point in the wall of the uterus.
00:09:01
Therefore, there's a small risk of this scar separating, or in fact bursting open or rupturing during the course of labour. So I should stress this is for the most common type of caesarean that's performed. This is extraordinarily uncommon to happen prior to the onset of labour.
00:09:22
We know that of the women who attempt a vaginal birth after a caesarean, there's approximately a 1 in 200 risk of some type of scar separation or scare rupture occurring during labour and in most of these instances that's not going to be a terribly serious event. The team of midwives and doctors that are looking after you will most likely recognise that there seems to be a problem occurring and will recommend the caesarian be carried out and provided this is done in a fairly prompt way, it's unlikely that there will be any serious outcome for either you or your baby.
00:10:01
You'll notice that I did say mostly, and we do have some fairly specific and fairly reliable numbers around the potential risks associated with VBAC in terms of a serious outcome for mother and baby. So it's important that we talk about those numbers.
00:10:20
So if you are attempting a VBAC, there's something like a 1 in 1000 or 1 in 1500 chance of something really serious going wrong that will have really major long term consequences for your baby and when we talk about major long term consequences we mean stillbirth, or your baby not surviving, or a brain injury to your baby due to lack of oxygen that will lead to a permanent disability.
00:10:50
Now something that happens to around 1 in 1000 women who are attempting a VBAC is certainly not a common event, but nevertheless it is something that does occur, and for those women where it happens and it is a tragic and catastrophic event.
00:11:08
The other thing that can occur if the scaling uterus ruptures is to cause some serious risks to the mother. So this can lead to significant bleeding into the abdominal cavity, so into the tummy, and can result in the need for a blood transfusion. There can be injury to other things so you can get a tear extending into the bladder, which can be quite challenging to repair. And if it's a really bad rupture, sometimes the only way to stop the bleeding is to do something as drastic as a hysterectomy. Now this is not common and this will occur in significantly less than 1 in a 1000 women who attempt a vaginal birth after caesarean, but nevertheless they are things that we need to be aware of and take these into account in making our decisions.
00:12:01
I also think it's very important that we keep these risks in some degree of perspective. For a woman who's not had a caesarean before, who's a low-risk woman in labour, there's also about a 1 in 1000 chance of something seriously going wrong during the course of labour that might have a significant impact on the long-term health and well-being of the child.
00:12:26
So, no matter which way we approach childbirth, there are always some types of small risks associated with the decisions that we make. Those figures that I quoted in terms of risks associated with vaginal birth after caesarean section apply to women who've only had one previous caesarean, and I'll talk about women who've had more than one caesarean a little bit later.
00:12:51
There are also some factors that are associated with an increased risk of scar rupture during labour. One of those things would be that if we use drugs to stimulate the contractions of your uterus.In other words, if we did an induction of labour, then we would use a drug called oxytocin to stimulate your uterine contractions. And we know that if we use oxytocin in somebody who's had a previous caesarean the risk of rupture and the risk of something serious going on goes up by a factor of about two times, so it doubles.
00:13:25
We also know that, or we think we know, that if there's a short interval between your pregnancies, risk of rupture increases. Now we would consider a short interval as an interval of less than 18 months between births. So this would mean if you had an interval of around 12 months since the birth of your last child until you get pregnant again, that you're in a safe interval in terms of your risk of VBAC, but if your pregnancies have occurred very close together such that the births are likely to be less than 18 months apart, there is probably an increased risk of scar rupture during labour in your subsequent pregnancy.
00:14:07
It can also be things about your previous caesarean that might increase your risk of scar rupture. So mostly with a caesarean it'll be performed through the lower part of the uterus without any of the incision on the uterus extending into the upper half of the uterus.
00:14:25
If there's been an incision or a tear extending into the upper part of the uterus during your previous caesarean then firstly the medical team will very likely have informed you about this event because it is quite uncommon. And secondly, if this has happened it changes the risk profile quite significantly, in that it increases the risk of rupture quite a lot for your subsequent pregnancy.
00:14:51
And that's why if you've had a caesarean before, we're quite keen on delving into some of the details and circumstances around that caesarean. So that's about sharing information with you about the risks and benefits of attempting vaginal birth after previous caesarean. The thing that's potentially going to be very important for you is the framework that you bring to that decision making. So what are your priorities?
00:15:17
Some women will come very much with the priority of maximising the chances of attempting a virginal birth because that's something they feel is very important for them. Other women or couples might come from a much more safety conscious perspective.
00:15:36
So, the information is the information, but how you process that information in a way that's most relevant to you and helps to guide you to the most appropriate decision for you and your pregnancy and your baby will vary greatly from individual to individual.
00:15:54
There may be additional information which is particularly pertinent to you, and we'll call these special circumstances. One of these I alluded to before, was women have had more than one previous caesarean.
00:16:07
The information to help guide our decision making around this is not quite as strong as for women who have only had one caesarean, so we do know that if you've had two previous caesareans, the risk of uterine scar rupture goes up quite significantly compared with one estimated probably to about double the risk.
00:16:25
Once we moved women who've had three or four previous caesareans, the risks become extremely difficult to calculate but the information we have suggests that the risks probably become quite high, and this would need to be discussed in an individualised way.
00:16:44
Finally, assuming that we've made a decision that we're going to go down the pathway of attempting a vaginal birth after your caesarean, what does your care during labour look like?
00:16:55
So firstly, we're going to try and avoid doing an induction of labour because we know that induction of labour doubles the risk of things going wrong.
00:17:05
Secondly, there are no limitations around your pain relief in labour. So you can access whatever form of pain relief you like. So an epidural is fine, you can breathe on gas, you can use morphine or pethidine if you wish.
00:17:20
Next, we'd like to see you reasonably early in the course of labour. This enables us to assess your baby’s well-being and assess the progress of your labour, both of which are important factors in attempting a VBAC. So, once you start to develop regular painful contractions, or your waters break, it's a good idea to call up the birth unit and make your way into hospital, probably a little bit earlier than you might otherwise do if you hadn't had a previous caesarean.
00:17:53
Another aspect of your care that will be a little bit different is if you're attempting a vaginal birth after a previous caesarean, then we like to continuously monitor your baby's heartbeat during the labour. This is because the baby's heartbeat tracing gives us the most reliable indicator of how things are progressing with the scar on your uterus. So, you remember that we talked about uterine scar rupture has domain risk associated with vaginal birth after caesarean, so the baby's heartbeat tracing is the most reliable indicator that there might be a problem developing with the scar.
00:18:34
Now for some women continuous monitoring can be an issue in that you may want to mobilise actively during labour. You might want to be in the shower. And most birth units nowadays will have telemetry monitoring systems, which means that state you can be hooked up to a fetal monitor without the need for wires and cables, and be able to mobilise and hop in the shower and move around the room reasonably comfortably without the encumbrance of being physically connected to a monitor. Otherwise your care and assessments during labour will be carried out in a in a fairly routine way.
00:19:13
Finally, I think it's important to say that there's very often no clear cut right or wrong answer around the questions involved in decision making for attempting vaginal birth after a previous caesarean, and it's important that you have an individualised discussion with your pregnancy care provider and come to a decision that you and your partner feel comfortable with.
00:19:37
Thank you for listening. I hope you found this information informative and enjoyable. We would welcome any feedback and if you have any suggestions for future episodes please reach out. Bye for now.
