In a slight departure from normal programming, I’m tackling perineal trauma today. This is a topic I have posted about before (like this, this, and this), and have contributed to research in this area (Allen, Small, & Lee, 2022).
A bit of background
In the birth-world, the term perineum is generally used to mean the area between the back of the vagina and in front of the anus (back passage). Tearing of the skin, vaginal wall, and the muscles and tissues that lie between them is common during vaginal birth. Less common is a tear that extends further, so it damages the muscles around the anus (the anal sphincter – this is called a third degree tear), or extends all the way into the anal canal (known as a fourth degree tear). Third and fourth degree tears are called severe perineal trauma.
(You’ll often see the term Obstetric Anal Sphincter Injury or OASI but I don’t use it. It’s not the obstetrician’s anal sphincter that is injured, and while an obstetrician might have been involved in the birth when severe perineal trauma occurs, they aren’t always. The term also suggests the injury is only to the anal sphincter when this isn’t the case. I’ll stick with severe perineal trauma.)
Preventing perineal trauma, and particularly severe perineal trauma, is a good idea. There are simple, effective, and proven ways to do this. (Here’s the Cochrane review about this.) There are some other things people THINK work, and that maybe have a bit of not-so-great evidence about them. Several countries around the world, including the UK and Australia, have smooshed together a combination of approaches aimed at reducing severe perineal trauma into a thing called a care bundle.
There are some problems with this approach. One of the problems is the assumption that if things A & B have been proven to work, and we think things C, D, & E should work, then doing A, B, C, D, & E for every woman will be even better than doing just A or just B or both. But of course we shouldn’t assume this will actually work. When introducing a change like this, research really should be built into the bundle to make sure that it does what it was meant to do, without introducing any unexpected downsides.
Did the Australian Perineal Care Bundle work?
In Australia there has been confusion about whether the Perineal Bundle was a research project or a quality improvement project (Allen, et al., 2023). The organisation responsible for it (Women’s Healthcare Australasia) have information on their website saying the bundle reduced severe perineal trauma, but their findings have not (yet, perhaps it is coming?) been published in a peer-reviewed journal where they can be subject to academic scrutiny. A team of researchers (independent from Women’s Healthcare Australasia), led by midwife Dr Nigel Lee, decided to tackle the question for themselves (Lee, et al., 2023).
To answer the question of whether the bundle reduced severe perineal trauma or not, they compared outcomes for 20,155 women who gave birth at a single Australian maternity service during 2011 – 2017, before the bundle was introduced, with outcomes for 6,273 women who gave birth between 2018 – 2020 after the bundle was introduced. Only women giving birth without the assistance of forceps or vacuum extraction, where the person assisting the birth was a midwife, and where the birth involved a single baby coming vertex first at term were included. Factors known to modify the chance of severe perineal trauma (like a birthweight of more than 4 kg, labour induction, being a first birth or the first birth after a caesarean section) were examined to see if they were more or less common between the two time periods, and adjustments were made when this was the case. This makes it more likely that any differences (or lack of difference) seen are due to the bundle, and not, for example, because women gave birth to bigger babies in the earlier time period.
The raw data showed the rate of severe perineal trauma was already falling before the bundle was introduced at this hospital – from 4.1% in 2012 to 1.9% in 2017. At the first time period measured after the bundle was introduced (2019) the rate was still 1.9%, then rose to 2.9% the following year. Rates of second degree trauma remain unchanged over the time period being examined, while the use of episiotomy increased steadily over time – starting at 4.8% in 2012, reaching 9.8% just prior to the bundle being implemented, and then to 11.5% in 2020 after the bundle was in place.
After mathematically taking into consideration factors that might influence the severe perineal trauma rate, they found bundle implementation did not change the rate of severe perineal trauma (aOR 0.86, 95% CI 0.71 – 1.04), almost increased second degree trauma (aOR 1.07, 95% CI 1.o – 1.13), and significantly increased the use of episiotomy (aOR 1.36, 95% CI 1.22 – 1.51). Looking at just women giving birth for the first time, the findings were the same but second degree trauma moved away from being close to statistically significant to not being significant. For women who had given birth before, there were no differences in the rates of severe perineal trauma or episiotomy, and an increase in second degree trauma (aOR 1.18, 95% CI 1.09 – 1.27).
Why didn’t the Perineal Care Bundle work?
For this group of women, the bundle didn’t do what it was meant to do (reduce the rate of severe perineal trauma), but did increase the use of episiotomy for some women, and second degree trauma for others. This is not what was meant to happen, clearly. Introducing the bundle gave midwives extra work and achieved less than expected. If some of the interventions included in the bundle don’t work, they may well dilute the effectiveness of those that do, making the overall combination ineffective.
There is also fresh new evidence that further undermines faith in one of the interventions included in the bundle.
Does the angle of incision matter?
Perineal trauma, whether deliberately created by episiotomy or arising by chance at birth, that points towards the anus, is believed to be more likely to tear into or through the anal muscles than when the angle points out to the side. Controlling the angle with a spontaneous tear is impossible, but it is easily done when performing an episiotomy. Traditional teaching about how to perform a mediolateral episiotomy advised the use of an angle 45 degrees away from the midline.
It seemed like a good idea to change teaching on how to perform an episiotomy and to move the angle even further away. Research examining the perineums of women who had an episiotomy performed (very precisely measured and marked) at 60 degrees from the midline, showed this resulted in a mean angle of 44 degrees at the time of repair (with a range from 32 to 59 degrees) (Kalis, et al., 2011). Special scissors (Episcissors-60) have been designed, marketed, and widely adopted to make it easy to see the 60 degree angle at the time the incision is being made.
At the time of bundle implementation, there was little research about whether they did what they were meant to do – reduce the episiotomy extending further than the initial incision in a way that resulted in damage to the anal sphincter. There has only been one randomised controlled trial, conducted in India and reported in 2015 (Sawant & Kumar, 2015) and it enrolled only 63 women. All women were giving birth for the first time, and 9 had an operative vaginal birth. The suture angle with the new scissors was 41 degrees and with the previous scissors was 28 degrees. One woman where the previous scissor were used experienced severe perineal trauma, none with the new scissors – the difference was not statistically significant.
Three other studies, not randomised controlled trials, have also been done. When all four were combined in a meta-analysis, the incidence of severe perineal trauma was reduced when the new scissors were used (Davikova, et al., 2020). Mathematically speaking, combining studies using different approaches is considered unsound. Yet this is what happened in this meta-analysis (one time series, one before-after study, one randomised controlled trial, and one service evaluation).
It’s not really a firm footing to stand on when recommending a significant change to practice. And the advice to use a 60 degree angle ignores the reality of women’s anatomy, as this angle results in a high rate of damage to the bulbs of the clitoris (Garner, et al., 2021).
So what’s the new evidence?
A team of researchers based in France (Evangelopoulos, et al., 2023) have taken a different angle (yes, that was a pun). They enrolled 219 women, all of whom had an episiotomy, and all had instrument assisted births. They didn’t describe whether the women were giving birth for the first time or not. With the woman’s permission, they took a photo of their perineum after the episiotomy had been repaired, and measured the angle. They then compared the size of the angle away from the midline with the rate of anal sphincter injury.
The rate of anal sphincter injury was the same, whether the angle of repair was more than 45 degrees, or 45 degrees or less. Looking in the other direction, the angle of the repair was the same whether women had severe perineal trauma or not. Remember the angle of repair is higher when the incision angle is higher.
While this evidence is far from conclusive, it does undermine the assumption that cutting a higher angle episiotomy will reduce the incidence of severe perineal trauma. It seems there should have been more time spent getting the basic science right on this one before introducing it in practice.
Sigh. We keep doing this. When will we learn?
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References
Allen, J., Small, K., & Lee, N. (2022, Feb). How a perineal care bundle impacts midwifery practice in Australian maternity hospitals: A critical, reflexive thematic analysis. Women & Birth, 35(1), e1-e9. https://doi.org/10.1016/j.wombi.2021.01.012
Divakova, O., Khunda, A., & Ballard, P. A. (2020, Mar). Episcissors-60 and obstetrics anal sphincter injury: a systematic review and meta-analysis. International urogynecology journal, 31(3), 605-612. https://doi.org/10.1007/s00192-019-03901-4
Evangelopoulos, N., Duraes, M., Cayrac, M., Galtier, F., Fritel, X., Gachon, B., & De Tayrac, R. (2023, Sep 1). Episiotomy practice in France and prevention of high-grade perineal tears at the time of operative vaginal delivery: a prospective multicentre ancillary cohort study. International Urogynecology Journal, (in press). https://doi.org/10.1007/s00192-023-05640-z
Garner, D. K., Patel, A. B., Hung, J., Castro, M., Segev, T. G., Plochocki, J. H., & Hall, M. I. (2021, Feb 2). Midline and mediolateral episiotomy: Risk assessment based on clinical anatomy. Diagnostics, 11(2). https://doi.org/10.3390/diagnostics11020221
Kalis, V., Landsmanova, J., Bednarova, B., Karbanova, J., Laine, K., & Rokyta, Z. (2011, Mar). Evaluation of the incision angle of mediolateral episiotomy at 60 degrees. International Journal of Gynaecology & Obstetrics, 112(3), 220-224. https://doi.org/10.1016/j.ijgo.2010.09.015
Lee, N., Allen, J., Jenkinson, B., Hurst, C., Gao, Y., & Kildea, S. (2023, Aug 17). A pre-post implementation study of a care bundle to reduce perineal trauma in unassisted births conducted by midwives. Women & Birth, in press. https://doi.org/10.1016/j.wombi.2023.08.003
Sawant, G., & Kumar, D. (2015). Randomized trial comparing episiotomies with Braun-Stadler episiotomy scissors and Episcissors-60TM®. Medical Devices: Evidence and Research, 8, 251–4. https://doi.org/10.2147/MDER.S83360
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Categories: New research
Tags: bundled care, Episiotomy, OASI, Perineal trauma
Birth Small Talk 
However severe perineum trauma is a relatively recent impact when giving g birth . The increase in induction , increased anxiety in second stage , ctg , pushing practices , position of mother , position of baby , mothers diet , mothers physique , parity , level of anxiety . In the pool or not .
Why would Finnish grip and episiotomy bring any benefit to spontaneous births ? Plus , some second tears are more problematic than small third but this is not evaluated I believe …..
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