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  • Writer's pictureGillian Holmes

Unpacking the OASI Bundle

If you’re pregnant, you may have heard of the OASI (Obstetric Anal Sphincter Injuries) bundle - or maybe you haven’t, in which case it’s worth checking if it’s being implemented in your local hospital - it’s recently been introduced in Gloucestershire Hospitals Trusts.

The OASI bundle is a set of interventions aimed at lowering the chances of severe tears during vaginal birth. Which sounds great, of course! But let’s take a closer look at what’s good about it and where it falls short.

What is the OASI Bundle?

The ‘bundle’ of interventions includes the midwife physically guiding the baby’s head as it emerges, holding a warm compress on the perineum with one hand and their other hand on the baby’s head. An episiotomy (cutting the perineum) may be performed, to direct a potential tear away from the rectum. Midwives will direct you through the pushing stage, instructing you on how and when to push or not. After the birth of the baby, during the postnatal check, a ‘digital rectal examination’ is performed – digital as in finger, not numbers…

Let’s unpick that a bit more…

Nobody wants to deal with the aftermath of a severe tear, so anything that reduces the risk is a win, right? Some perineal damage is not unusual but most small tears or grazes heal well and it’s only damage that extends into the muscle layer that is considered a severe complication – an OASI. Does the bundle reduce the numbers of people suffering OASI? One study concluded that “the OASI rate decreased from 3.3% before to 3.0% after care bundle implementation.” (Gurol-Urganci et al 2020)… which isn’t a huge reduction.


So as well as the bundle not making very much difference in outcomes, could it actually be causing more problems than it solves, in some cases?


In order for some of the parts of the bundle to be implemented it’s possible that women and birthing people might be encouraged to adopt less beneficial positions – for the warm compress to be applied, for example. Being touched on your perineum as you birth your baby might be the last thing you want to feel, and you might not want the midwife’s hands to be the first thing to touch your baby’s head… importantly a Cochrane review (the best evidence) concluded that a ‘hands on’ birth does not reduce perineal trauma.


Episiotomy can lead to an increase in post partum haemorrhage according to some research: and of course a cut can lead to further tearing.. let’s not forget that an episiotomy is perineal damage in itself, too.


Finally – the digital rectal (finger up the bum) examination… now in certain circumstances it might be sensible to accept this indignity and discomfort in order for a midwife to check if a vaginal tear has extended into the muscle. However, if the perineum is intact, is it really necessary for everyone who’s just given birth to be subjected to it? Surely midwives can make a judgement call on whether it’s necessary to offer it on a case by case basis.


I’ve selected my words carefully in that last sentence: because ultimately everything in the bundle is an offer – and as with everything in your care throughout pregnancy and in labour, you can choose whether to accept or decline any offers.


But it’s worth being aware of what is on offer, and  to consider how you think you’ll feel about it before you are in the throes of labour!


While the OASI bundle has good intentions, it’s far from perfect. We need to keep researching to understand its long-term effects better and make sure it’s being implemented (offered) appropriately and ethically. Most importantly, we must address the root causes of tears in childbirth: by doing that, we can truly make childbirth safer and more comfortable. The interventions people face in medicalised childbirth are often themselves the cause of perineal trauma and there are things that women and birthing people can do themselves, in pregnancy and during labour to avoid or limit damage - see my previous blog post ‘Giving Birth – can you avoid a tear?’


This week I've been reading Sara Wickham and Rachel Reed in researching this post. If you'd like to read them direct, go to:








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Apr 16

Great blog, thanks Gillian.

Interestingly, obstetrician Jim Thornton had reservations about the OASI care bundle too. His evaluation: “a well-conducted study, but an unclear result” — more at:

My feeling is that, as with everything, people should have/be given as much information as possible to make informed choices about their care. Amongst various other factors the risk of a severe tear can be reduced by perineal massage from 35 weeks, having a warm compress against the perineum during pushing (some people genuinely do appreciate this), spontaneous vaginal birth ie without forceps or ventouse, in midwifery led unit or at home (if low risk), avoiding induction and epidural where possible, and remaining active throughout labour and birth. being free and…

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