I want to talk to you today about the stretch and sweep, otherwise known as a membrane sweep so if you’ve no idea what I’m talking about then I’ll explain what they are and then we’ll go through and talk about the reasons they’re offered, the benefits and risks of the procedure, evidence and anecdotes. I’m gonna include the research and the stats too so hopefully it will help you make an informed decision about whether or not you’d like to go for one at the end of your pregnancy. I’m not trying to influence your decisions, you know this by now, I hope to have a positive impact on your pregnancy and your birth but I don’t want you to feel like i’m swaying you in a direction that doesn’t feel true to you because that’s not my intention however I will give my opinion at the end of this read, take it or leave it!
So, what is a membrane sweep? A procedure done by a midwife or doctor whilst they are carrying out a vaginal examination, they putt a finger inside your cervix (if they can) and make a circular sweeping movement to separate the membranes (the bag of waters) from the cervix in an attempt to stimulate the release of the hormone prostaglandin, which is one of the hormones which kickstarts and drives forward your labour. The theory is that by producing this hormone then they may be able to kickstart your labour in the hope that the rest of your body gets the memo and joins in. It’s being done to try and start labour, before your body is ready to go into labour, because if your body was ready to go into labour - it would have done so already, so it’s a form of induction. It is so often sold to us as a way to AVOID induction, ‘book in for a stretch and sweep at 40 weeks to avoid going overdue and needing an induction’ but it IS an induction in itself, and like all induction methods and all interventions in birth there are risks involved.
Do they actually work? Well we don’t really know, sure there are some studies on if people have gone in to labour after having them and some not so reassuring statistics, but realistically we have no bloody idea whether the sweep worked or whether it was just your body. What I mean by that is, did the sweep cause the person in question to go into labour or was your body just ready to go into labour anyway and even without the sweep would have started up labour at that time anyway, we have absolutely no way of knowing. What is classed as a successful sweep is one that brings labour on within 24-48 hours of the sweep being performed, but most people having them are on, or often past, their estimated due date, so the likelihood of them going into labour within 24-48 hours of the sweep is heightened anyway. So yep, we don’t actually know if the sweep works at all, and the research that has been done on them is unconvincing anyway, the most recent Cochrane Review which compared membrane sweeping with no sweep or a sham treatment concluded that the likelihood of spontaneous labour following the membrane sweep was only 21% and this was looking at a wide range of evidence and research and collating lots of different studies. So that’s what you’re weighing up first and foremost when deciding whether to have one or not, do you like those odds - around a ⅕ chance of it even working.
When I was researching this topic I actually found a fascinating study that had been done in 2011 which looked at evaluating cervical length changes after membrane sweeping and the effect of cervical shortening on pregnancy outcomes, the cervix starts off long and thick and for birth to move forward what needs to happen is a shortening and thinning out of the cervix, incredibly important because a baby cannot descend through a long, hard, closed cervix, yet this study found and I quote “Membrane sweeping was associated with lengthening of the cervix. A shortened cervix after sweeping was independently predictive of vaginal delivery.” So membrane sweeps are often causing the cervix to lengthen, the absolute opposite of what we need to be happening to help our bodies go into labour, the mind boggles! This was a small scale study, I do think it’s important to mention and no other research exists on this specific topic as far as I can see but still it’s pretty fascinating stuff isn’t it, like what good are those prostaglandins doing if the process of the sweep itself is further lengthening the cervix? It’s food for thought.
Other risks? There are other risks involved such as introducing infection, the possibility of breaking the waters, setting off a prolonged labour pattern which can be painful or exhausting and cause the birther to feel they need assistance they otherwise wouldn’t have. It’s a slippery slope and something I don’t feel we talk about enough, especially to first time mothers who are not 100% sure what to expect from labour anyway, a prolonged experience, or a start/stop experience, from a membrane sweep starting your labour off before your body or your baby were truly ready can be incredibly difficult to deal with.
What are the benefits? The Cochrane Review I just mentioned found that, “Women reported feeling positive about membrane sweeping. While acknowledging that it may be uncomfortable, they felt the benefits outweighed the harms and most (around 88% in one study) would recommend it to other women” It then went on to state that the key finding were as follows “Compared with no intervention or a sham sweep (40 studies involving 6548 women), allocated to membrane sweeping may be more likely to have spontaneous onset of labour, but we found no clear difference in unassisted vaginal births. We also found no clear differences between the groups for caesarean section, instrumental vaginal births or serious illness or death of the mother or baby.”
To break that down - the pros - more likely to have spontaneous onset of labour, so to avoid further induction methods to START the labour. This doesn’t cover augmenting the labour once it has started, so the sweep may make spontaneous labour more likely but doesn’t mean that these women avoided the induction all together, they may still have ended up with artificial rupturing of membranes or an oxytocin infusion to speed things up. It then says “but we found no clear difference in unassisted vaginal births” so it doesn’t make you more likely to have an unassisted vaginal birth, only for the labour to start spontaneously. And if you’ve had a sweep did the labour really even start spontaneously? This is a grey area. It did however say said that the majority of women still felt positive of their experience regardless though!
And that’s the research, and everyone will interpret that differently and that’s a good thing. We’re all different and for some of us, an unassisted vaginal birth is the highest priority but there may be important reasons why we NEED a little assistance to go into labour a little bit earlier and for those people, the offer of a sweep may be exactly what they need to give their bodies a chance to go into labour without having to rely on any more pharmacological options, or even for those in places where pharmacological options are not widely available for example. So I’m not naive enough to think that absolutely everyone out there can have a plain sailing serene pregnancy and spontaneous undisturbed vaginal birth, ‘cause some of us and some of our babies need a bit of help and for those people a sweep is probably a comfortable and welcome option.
As always, do what feels right for you and your baby.
And as for my opinion, I had one and I did go into labour a few hours later, but would I recommend? Nope. I know I was one of the lucky ones who got away without any side effects or disruptions to my labour, but I know enough women who weren’t so fortunate and I’ve seen the devastating effects of a stretch and sweep play out too many times and wreck too many births for me to go ahead and advocate for them, especially when the evidence surrounding them is sketchy at best. But as above, if it’s the best of a bad bunch of options for you and you’ve asked yourself all of the right questions before making the decision then go for it. I’d recommend utilising hypnobirthing breathing techniques for the procedure, having a hot water bottle on hand to deal with any cramping or pain in the aftermath and planning for a potentially long early labour as a result ( so ensure to rest a LOT, have adequate nutrition and snacks on hand and don’t try to “chase” the labour).
I hope this was helpful, speak soon.
If you’d like to learn more:
Check out my digital hypnobirthing course here - https://www.thedungareedoula.co.uk/onlinecourse
Check out my virtual doula packages here - https://www.thedungareedoula.co.uk/doula
Check out my podcast ‘The Doula’s Guide To Preparing For Your Birth’ available on all podcast platforms.
Meg x
- - - - - - - - - - - -
References
Effect of membrane sweeping on cervical length by transvaginal ultrasonography and impact of cervical shortening on cesarean delivery: click hereCochrane review - Membrane sweeping for induction of labour: click hereThe Historical Practice of “Membrane Sweep” to Initiate Labour: Does it Have a Role in Contemporary Obstetric Practice: click hereBirth Hijacked – The Ritual Membrane Sweep: click here
Comments