Episode 165 Oxytocin Use

Discover  the hormone oxytocin and its role in the birthing process  in the latest ObsPod episode. We unravel the dual nature of this potent hormone, once an unquestioned staple in Active Management of Labour.  Listen as we share an engaging conversation about its physiological impacts, the delicate balancing act required for its use in inducing labor, and the critical examination of its application in natural labor progression.

We discuss use of oxytocin over time,  We tackle the tough questions about its contribution to caesarean birth rates and dissect the role that confirmation bias has played in obstetric intervention. With a focus on the value of one-to-one midwifery care and the potential consequences of oxytocin use, such as hyperstimulation and fetal distress, our discussion paints a comprehensive picture of the complexities involved in labor management. We take a  look at the risks associated with administering oxytocin during labor. Highlighting scenarios where its use is beneficial against those where caution is paramount, we stress the importance of respecting natural labor progression, discussing alternatives. I extend an invitation to our listeners to contribute to the conversation and support the ObsPod, remember that this episode isn't just about the clinical—it's about informed consent and empowering women to make the right choices for their births.

Want to know more?
https://obgyn.onlinelibrary.wiley.com/doi/10.1111/j.1471-0528.1996.tb09734.x
https://www.cochrane.org/CD007123/PREG_the-effectuse-of-the-drug-oxytocin-as-a-treatment-for-slow-progress-in-labour
https://www.nice.org.uk/guidance/ng235
https://www.nice.org.uk/guidance/ng235/evidence/f-use-of-oxytocin-in-the-first-or-second-stage-of-labour-pdf-13186672963

Thank you all for listening, My name is Florence Wilcock I am an NHS doctor working as an obstetrician, specialising in the care of both mother and baby during pregnancy and birth. If you have enjoyed my podcast please do continue to subscribe, rate, review and recommend my podcast on your podcast provider.
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Transcript

Speaker 1: 0:00

Hello, my name is Florence. Welcome to the ObsPod. I'm an NHS obstetrician hoping to share some thoughts and experiences about my working life. Perhaps you enjoy Call the Midwife. Maybe birth fascinates you, or you're simply curious about what exactly an obstetrician is. You might be pregnant and preparing for birth. Perhaps you work in maternity and want to know what makes your obstetric colleagues tick, or you want some fresh ideas and inspiration. Whichever of these is the case and, for that matter, anyone else that's interested, the ObsPod is for you.

Speaker 1: 0:49

Episode 165, oxytocin Use. Today's episode covers a topic that, it suddenly occurred to me, might be useful to people working in the maternity space and those using maternity services, and that is the use of oxytocin. And I almost called this episode use or abuse, because it's a tricky one. The use of oxytocin can be very beneficial in some circumstances, but far less than we probably use it, and therefore I thought I would unpick that a little bit today. The reason I thought about doing this episode is I had a slight epiphany in my last episode when I was talking to Dr Kirsten Small about intermittent oscultation. Kirsten discussed the fact that we're very good as human beings at telling stories, making up stories that explain the world around us that we don't understand, and then believing those stories and not realizing that those are just that they are stories. So I had a moment of realization when I was a very junior obstetrician and had just started out in my training. I believed in just that. I believed in a story called Active Management of Labour. And I wasn't the only one that believed in this story. Many, many units believed in this story. And I guess one of the things about having been in a career for 20 or 30 years means that over time it's inevitable that some of the things you did when you were more junior or earlier on in your career become less well accepted practice, because the science, the medicine evolves and you learn and understand. And it may be that I'm just telling myself a series of new stories and that they're no better than the old story, but I thought I would discuss a little bit my thoughts and reflections on my own experience of oxytocin usage.

Speaker 1: 3:21

Oxytocin, what is it? I'm going to go right back to the physiology. Oxytocin we're all familiar with. People often call it the love hormone, which has always seemed to me incredibly strange given its use in obstetrics. But oxytocin is a hormone released from the posterior pituitary gland, so that's an endocrine gland in the brain. The release of oxytocin, naturally, is controlled by nerve impulses that come down from the hypothalamus, down through the nerves to the posterior pituitary. And alongside oxytocin, there is another drug, vasopressin, that is produced from the posterior pituitary, and it's very similar in structure, and I'll come on to why that's important shortly.

Speaker 1: 4:28

So oxytocin is released from the posterior pituitary gland as the result of nerve stimulation, and that might be from the womb, the uterus or from the breast, and that's often why people talk about a bit of breast massage or stimulation or expressing milk to help improve oxytocin levels in labor. What the oxytocin does in the womb is has an effect on the receptors in the womb muscle and causes stimulation and contraction. What is the missing bit of the jigsaw is, though, that at some points the womb is completely unresponsive or has very little response to oxytocin, and at some points has lots of receptors. So what happens is that the womb's sensitivity to oxytocin increases towards the end of pregnancy and in labor, so that in early pregnancy, oxytocin has very little effect the womb is very insensitive, whereas in labor, and particularly in established labor, the womb is very sensitive, so that very small doses of oxytocin can cause a significant increase in the number, duration and strength of contractions. So, in labor, a woman's body will release oxytocin, and as the labor gets going the contractions will increase, partly due to an increase in the sensitivity of the womb to respond to the oxytocin being released. But the oxytocin does have some downsides too. Remember I said that structure is very similar to vasopressin, also produced by the posterior pituitary, and because of this the oxytocin has an effect on the kidneys, which is called anti-diuretic, which can lead to water retention in labor, and if you want to know more about that, you can go back to my episode 147 on fluid balance and about water intoxication in pregnancy. So that is oxytocin naturally produced by the body, by the woman triggering labor, that's not a problem and then, once she's had her baby, she'll continue to release oxytocin as the baby starts to feed and stimulate the breast, and it's a key hormone in the production of breast milk and breast feeding.

Speaker 1: 7:40

What I'm going to talk about today, though, is the use of oxytocin, or centosin, on synthetic oxytocin and in some areas of the world it's called pitocin by midwives and obstetricians, and this kind of breaks into two parts If one is having an induction of labor, and I've talked about this also previously on the podcast. We are trying to initiate labor. We will use a combination, usually of prostagandins and oxytocin, so once we have ripened the cervix and hopefully initiated some contractions, we'll then often need oxytocin. The woman is not contracting and we need to give her something to make the womb contract. And whilst we need to be cautious doing that, I don't disagree with that as an approach.

Speaker 1: 9:00

What I want to focus on instead is the use of oxytocin or centosin on in established labor. That is, the woman has come in in labor, the labor has started spontaneously, her body's initiated it and then for some reason usually the fact that labor is slow we decide to give her oxytocin. Maybe the contractions have spaced out, or maybe the progress, the dilatation and descent of the head, is slow and we want to give her oxytocin. And this is where active management of labor comes in. And this is a story that I very much subscribed to for a significant part of my career the idea that if a woman was progressing slowly, that if we gave her oxytocin judiciously, carefully, at the right moment, we might change the outcome of that labor. So we might have a woman who was in our minds heading for potential caesarean birth because of very slow progress in labor or stalled labor, and we would give oxytocin and we would congratulate ourselves that we potentially corrected her labor and managed to avoid her having a caesarean birth. And it's tricky for me to make this podcast and admit that this is something I'm very much subscribed to.

Speaker 1: 10:56

I used to get irritated when I came onto the labor ward and took over and discovered a woman that had been languishing in labor for a very long period of time and people hadn't acted, they hadn't performed an amniotomy that is breaking the waters, they hadn't given her stintocin on and therefore I felt that I was being left with a situation which was beyond rescue. She was now in a situation where she was inevitably going to need a caesarean birth. And that very much comes back to the way we're taught about the mechanics of labor, the power, the passage, the passenger, and therefore one of the things I could adjust was the power, the power of contractions, by prescribing centosinom, and it seemed to me bad obstetrics, bad medicine, if I didn't give the woman the drug that I felt could make a difference. Let's take a step back and think where did this story come from Well, it came from Ireland.

Speaker 1: 12:19

In the 1960s and 1970s in Dublin an obstetrician, o'driscoll, introduced active management of labor, and that was once a woman was diagnosed as being in established labor. They had their waters broken and if they were dilating at less than one centimetre per hour they were given synthetic oxytocin to correct their labor and I'm not kidding, that was the language used correct their labor. These are women in spontaneous labor and in the early work that was published, around 55% of first time mothers were given oxytocin during their labor. That's a phenomenally high number. Remember, these are not women that are being induced. These are women who've come in in labor so effectively. We're saying more than 50% of women. Their body doesn't know how to labor and when you look back at that evidence, this led to a quicker turnover of women through their labor ward. The labor was faster. They were aiming for a woman's labor to be less than 12 hours. That means you can maximize the efficiency of your labor ward because the quicker women give birth, the quicker the midwife can look after the next woman and the quicker a room becomes available to do so and therefore women potentially might like it because the labor is shorter and staff like it because there's more efficiency and flow through the unit and if you look back at that work it does say that but somehow, a bit like Chinese whispers, that story gets changed into oh, they actually improved the outcome of those women because they tied it into the rate of cesarean birth.

Speaker 1: 14:52

Now I started my career in 1994, that's when I started in obstetrics and to some degree it's not my fault that these were the stories I believed because at that time this was very much in vogue. We drew lines on the pategram action lines and to think about this topic today I've gone back through my training portfolio where I've got audits that I've done to look at whether midwives were following the guidance and following those action lines and appropriately requesting the doctor's review and start centosinone if a woman's progress was slow. People were dealing with rising caesarean rates across the western world and people were looking for a way to reduce that, seeing that as a bad thing and I know that's a controversial statement in itself these days, but unless a woman wants a caesarean, we should be keeping a caesarean to a minimum, to his major surgery. It's not how the body was designed to give birth. So people were looking around to try and reduce the rising caesarean rate. But looking at and thinking about this topic for today's episode, I quickly discovered some papers published in 1996. So only a couple of years after I got started in obstetrics that clearly demonstrated that the early use of amniotomy and oxytocin versus using it later in labor didn't make any difference to outcomes, so did not have an effect on the caesarean section rate, and that more important were things that we take for granted now, such as one to one mid-riff free care and support in labor, rather than the oxytocin itself. I am interested that this study compared early use of oxytocin with selective use rather than with no use of oxytocin at all, and that in itself to me shows part of the mindset of the time in which we were practicing.

Speaker 1: 17:38

So when I reflect, I'm thinking why has it taken me a really, really long time to lose that firm belief that using centosin would reduce the chance of caesarean birth? And you might think that on the labor ward you would see that that you'd see it didn't make any difference and therefore you would quickly change your beliefs. But actually the opposite is true. You would see women that you'd given centosin on to have a vaginal birth and rather than realizing that actually, given time, they probably would have had a vaginal birth. Anyway, you would think, aha, that's because I corrected her labor, I gave her oxytocin and now she's had a vaginal birth. Fantastic result. I did the right thing. And I guess some of that is confirmation bias, isn't it? And it's not realizing that actually left her own devices, that woman would have had a vaginal birth.

Speaker 1: 18:53

Anyway, the other thing that I believed was that if there was a male position so the baby was back to back, that using oxytocin might help the rotation of that baby. It might help with more effective, more powerful contractions. That would help the baby with its rotation and therefore help correct that. And maybe that was going to be how I was going to avoid a caesarean birth. And alongside this, we had the story that oxytocin is a bad thing, so giving centosin on could cause fetal distress, and that was very real. We didn't know that. But equally, I remember once arguing with a professor about this, because he was saying if there was fetal distress, one needed to turn off the oxytocin and give the baby a break, whereas I was thinking if I turned off the oxytocin and gave the baby a break, great, but that baby would never be born unless I did a cesarean. So I wanted to use the oxytocin, but use it carefully.

Speaker 1: 20:31

Let's think about what's the downside of oxytocin. Well, it can cause hypostimulation, so too many contractions, one on top of the other because you're overstimulating the wound, and that can cause fetal distress. So it can cause decelerations in the baby's heartbeat and in that situation we need to stop the oxytocin. It can mean the woman has what we call no resting time, so the wound doesn't properly relax between contractions, or she can be having contractions, maybe more than five in 10 minutes, so that she and the baby don't get any rest by any breathing space in between. Therefore, we have to use oxytocin, since it's not, extremely carefully and we have to consider is this baby fit and able to cope with the use of oxytocin? And these days in my unit we talk a lot about is this baby fit for labour when we're thinking about birth, and sometimes we do a cesarean because this baby isn't going to be able to cope with oxytocin in an induction process.

Speaker 1: 21:53

And of course, the downsides aren't all for the baby, they're a downsides for the woman. Not only could she experience considerable pain if she's hyper stimulated, although often women with oxytocin will choose an epidural, partly for the reason that they feel the contractions are more intense because we're forcing her body to do something that it's not naturally generating and pacing. But also, if we have a woman on oxytocin for a long period of time, then those oxytocin receptors potentially get saturated, and when we want the woman to contract after she's had her baby, so we've ended up doing the inevitable cesarean, or she has given birth vaginally. The womb has then been flogged and she's more likely to have a postpartum hemorrhage. There's plenty of evidence of this when I've done reviews of cases where women's hemorrhaged, and also plenty of evidence about poor use of centosin on causing fetal distress a worst case, long-term harm to the baby.

Speaker 1: 23:26

If you look at medical legal statistics and all the initiatives looking at improving outcomes for babies and reducing hypoxic, ischemic and kephalopathy HIE, centosin on is ever present as a considerable risk factor and that's why I was thinking about calling this episode use and abuse. So is there ever a situation in which we should be using centosin on spontaneous labour? And there probably is, but I now use it far less than I ever did. If you look at the nice guidance, it clearly says that if a woman is beyond five centimetres dilated. So she's in her well-established spontaneous labour, that there is no benefit to using centosin on in terms of the outcome of cesarean or vaginal birth, but that it may speed up her labour, shorten it by up to two hours. And these days in my unit partly thanks to Susanna Pereira, who has now left us but did an enormous amount of work on people monitoring in labour we really stopped using centosin on in spontaneous labour, so that we use it hardly at all, particularly if a woman is in the latter stages of labour maybe seven centimetres or beyond and we think instead about the position of the baby, what we can do naturally, such as breast stimulation or biomechanics, because if her body isn't progressing to a vaginal birth, then all we're doing by adding centosin on is increasing the risks for both her risk of bleeding and her baby's risk of distress and injury, and we're potentially using those very strong, powerful contractions to wedge the baby into the pelvis in a way that it isn't progressively descending and rotating and doing all the things we need it to do.

Speaker 1: 26:16

It's just impacting it and this is a very real negative consequence of the action we're taking, and you can see this in the fact that we now have algorithms and guidance on how to manage an impacted fetal head at cesarean and that this incidence is increasing, and one of the associations with this situation is augmentation and use of centosin. On the other very real complication associated with Centosanon in this obstructive situation is that of uterine rupture, and we often think of the womb rupturing in women that have had a previous cesarean birth, a rupture along the cesarean scar, and it's true that that increases with the use of Centosanon. But equally, if one has a woman who's had babies before multi-paras women and we use Centosanonon in a situation where her labor is obstructed, she can rupture her uterus, which is extremely dangerous for both her and her baby. Rupture is not something we see in women having their first baby, but is a very real factor that we need to consider extremely carefully when we're considering the use of Centosanon in these specific situations, and we really do need to proceed with caution, but also having fully explained to the woman the praise and cons so that she can make her own individual, well-informed decision about whether to proceed. So we need to be even more reluctant to use Centosanon in multi-paras women.

Speaker 1: 28:38

Let's go back to think about those first-time mums who've come in in spontaneous labor who I may or may not be thinking should have Centosanon. What am I considering before I take the decision or make a recommendation to them? So if I'm going to use Centosanon in this situation, we need to do a very careful vaginal examination to see are there any signs of any obstruction, any soft tissue swelling cappert on the baby's head, any moulding, any malposition, any suggestion that this labor is obstructed? What's her urine like? Is it bloodstained? How is she coping and how frequent are the contractions? And maybe maybe, if all those things are okay and maybe her contractions are quite spaced out, maybe once in every 10 minutes and once we've had a really good conversation with her about actually this might help. It probably won't change the outcome in terms of whether you have a caesarean or a vaginal birth, but it may make things a bit quicker, may make your labor a bit shorter, reaching that inevitable outcome. So would you like to try it?

Speaker 1: 30:05

So we need to have a good conversation with women in labor if we're going to use it, and that in itself is difficult unless she's already chosen an epidural, because having a conversation with a woman about this when she's contracting strongly and considering that to be informed consent can be really tough. So, essentially, women are in some ways not more sensible than us. So a lot of women have done so. Anti-natal classes a lot of women are frightened or scared of our sintation. On drip a lot of women are reluctant to have the drip I see this quite a lot, even in induction of labor and they don't want it. They will decline it and that's okay. That's informed consent. It is much harder when you're having an induction.

Speaker 1: 31:03

With an induction, it's highly likely, having a first baby, that you will require some sintation on to get your labor started. Not all the time, sometimes prostaglandins will be sufficient, but it's much more likely that we will need it. But then again, what will often happen is we'll start it, your body will start responding and then your body will take over. We will often then be able to turn the sintation on down, reduce the dose and turn it off. The final thing I want to talk about is when we do have that hypostimulation with Centosin on. What do we do? Well, we turn it off and we wait. We wait and see how the baby recovers and how the contraction space out. But what do we then do? Do we turn it back on?

Speaker 1: 32:04

And I'd like you to have a little look at a new interpartum care evidence review that was just published at the end of last year and that is around the use of restarting oxytocin once hypostimulation has happened and what dose it should be restarted and after what time period. And the answer is that, having examined all the evidence that there's no consensus In this review, they have decided that the recommendation should be contracting every three to four times in ten minutes and if there are more than four contractions in ten minutes, oxytocin should be reduced or stopped. And that's a new thing because the nice guidance used to say four to five in ten minutes. So that's a significant change. They acknowledge the fact that oxytocin is a very powerful drug and has an increased risk of adverse outcomes, but they didn't find any kind of agreement as to what dose it should be restarted and timing. So they did agree that the general consensus of restarting after 30 minutes is likely to be okay, but again, no firm evidence.

Speaker 1: 33:41

And they emphasized a lot the need for an obstetrician and midwife to look at the whole clinical picture and also take into account the woman's wishes, because to have people rushing, turn off your drip and then half an hour later tell you they want to turn it on despite whatever adverse event has just happened to your baby is extremely anxiety-provoking and worrying. So my zesty bit is remember this is an extraordinarily powerful drug that we sometimes give out almost like smarties on the label board and really, for a drug that is in use in every label board in the country, it is quite shocking that we have so little evidence. Remember that it won't change the outcome in terms of mode of birth, so whether you're going to have a vaginal birth or caesarean, it won't make a difference, but it may make a difference to the speed of your labor, but also it can have a significant negative impact. So try and think about using oxytocin, manius and induction medication rather than for use in spontaneous labor. And when and if you do use it in spontaneous labor, you've got to be extremely cautious and really careful. And if you're a pregnant woman listening to this, then don't be afraid of centosinone, because it isn't the drug itself, it's the way we're using it. So when people talk to you about the use of centosinone, the key thing to keep in your mind is did you go into labor naturally or not? If you went into labor naturally, it's unlikely that you should need centosinone and it's not going to make a difference to which way your baby is born, whereas if you're having an induction it's much more likely that it will be of some benefit. So I hope that's not been too much rambling. I hope that's been useful, my thoughts on the use of centosinone and I'd love to know other people's thoughts and opinions, because I still think we're wedded to that story that it makes a difference. Thanks for listening.

Speaker 1: 36:16

I very much hope you found this episode of the OBS pod interesting. If you have, it be fantastic if you could subscribe, rate and review on whatever platform you find your podcasts, as well as recommending the OBS pod to anyone you think might find it interesting. There's also tons of episodes to explore in my back catalog from clinical topics, my career and journey as an obstetrician and life in the NHS more generally. I'd like to assure women I care for that I take confidentiality very seriously and take great care not to use any patient identifiable information unless I have expressly asked the permission of the person involved on that rare occasion when it's been absolutely necessary. If you found this episode interesting and want to explore the subject a little more deeply, don't forget to take a look at the programme notes where I've attached some links.

Speaker 1: 37:29

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