The Science of Pain

I find pain fascinating*, especially after experiencing plenty of it in childbirth. It seems so basic a thing that it’s easy to assume modern medicine would have pain all figured out, but it really really doesn’t and not just because of a lack of basic biological knowledge (although that is a part of it). Everyone’s experience of pain is different so how can you impartially, scientifically, measure it?  If you’ve been through childbirth could you accurately describe the pain? Could you compare the pain you experienced with that of another women? Probably not, psychology and circumstance are every bit as important as what is physically going on and what may be tolerable to one person may be unbearable agony to another and not through any particular weakness or wimpyness on their part.

So what is the best way to manage pain in labour? Given how long women have been doing the birth thing you’d think there would centuries worth of research, but there just isn’t. In fact no one even thought to try until a little over a hundred years ago, prior to that childbirth was just one of those curses that women must bear for Eve’s sin – if mothers are in pain, if some of them even die? Well too bad girls, should have stayed away from that apple!

Thankfully though we live in a slightly more enlightened age and some studies have been attempting to asses the effectiveness of various different types of pain relief. The Cochrane Library is an organisation that reviews publications on specific topics and by comparing the quality and results of all these papers, tries to give a review of what we know – and how reliably we know it. They recently published an overview of studies into pain management in labour. After looking at reviews of a total of 312 different trials they grouped pain relief methods into three sets:

What Works:
Epidural, Entonox (gas and air)

What May Work:
Immersion in Water, Relaxation, Acupuncture, Massage, Local anaesthetic nerve blocks, Sedatives (non-opioid)

Insufficient Evidence:
Hypnosis, Biofeedback, Sterile Water Injection, Aromatherapy, TENS, Opioid drugs (eg, pethadine)

So slap everyone on entonox and epidural and forget about the rest right? Of course, sadly, it’s not that simple. While there is a lot of evidence that the “what works” techniques are effective, they also tend to have a lot of side effects. Gas and air makes many people feel sick, epidurals increase the likelihood of needing an instrumental delivery etc. etc. There is less evidence in favour of the “may work” group, often only one or two small studies, but they tend to have few if any side effects. Some of the techniques in the “insufficient evidence” group are especially interesting. TENS is often recommended by midwives, but there is very little solid evidence for it’s effectiveness, opioid drugs get a bad press as there is a concern that (amoungst other things) they will reduce the likelihood of breast feeding, yet only two, of the 57 opioids studies reviewed, looked at breast feeding as an outcome.

So where does this leave us? Is the review all a bit pointless because it can’t tell us to pop everyone on an epidural and to avoid aromatherapy like a sweet smelling plague? I think it would be a shame if we gave in that easily. What this review highlights is that far more work is needed to determine how effective each option is, how likely and how severe side effects are and importantly how much someones individual personality and circumstances are likely to influence this effectiveness. I’ve said it before and I’ll say it again – pregnant women aren’t silly, hysterical creatures, if given the facts clearly, and early enough in the pregnancy that it’s not all a bit too immanent, then most will be able to make intelligent, rational decisions about what is best for them. Without this we will continue to have to put our faith in midwives, antenatal teachers and friends and family  to advise us on this issue, and although these people may be well meaning, their own experiences will heavily influence their opinions of what works and what doesn’t.

Having had plenty of time to try out a few things I know that my own experience of various pain relief methods doesn’t exactly tally with this report. But I’m also aware that my state of mind influenced this. Things that worked brilliantly when I thought it was all going well, seemed utterly useless once I knew I was headed for theatre, in fact I think there is another whole blog post about the SouthwarkBelle guide to pain relief, but I may just have ranted enough for today…

*not in a creepy serial killer sort of a way, just to be clear.

6 responses to “The Science of Pain”

  1. Interesting read. I coped without pain relief twice and I think more women should be encouraged to try to go as long as possible without, our bodies are made for labour afterall. But at the same time I agree women deal with pain differently and if they require help they should be provided with it x


  2. Hi, thanks for commenting, you've actually raised a couple of points I keep meaning to raise on this blog:

    As a biologist who has studied human evolution (quite a while ago to be fair!)I've never really agreed with the idea that our bodies are made for labour. I think it would be more acuarate to say that our bodies have evolved as a compromise so that for the majority Labour is fine.

    I'm also wary of any policy to encourage women to go without pain relief. for some this would indeed be helpful, but for others it can lead to a crushing sense of failure if they can't live up to expectations (I've seen this at first hand and it can be far worse than many people would think)

    I've heard similar comments before from people who have had relatively quick and straightforward births (of course I don't know if that also applies to you). They have had a very positive experience of birth, feel (justifyibly) proud of themselves and want other women to be able to share in this. But of course that opinon is effected by their own experience, (as I am sure my opinions are!)

    Until we have a far better understanding of both the biology and psychology of pain I'd prefer to see woemen just given the facts and only offered opinions and advice if they ask for it. To do otherwise seems to automatically assume that women are too scared and emotional to make rational decisions, which feels horribly victorian to me.


  3. Completely agree – for me labour was short and safe, and although horribly painful, nothing compared to the pain of acute pancreatitis. I managed with a bath and G&A even though I went from period pains to 2 minutes on, 2 minutes off full on contractions in the space of 5 minutes. But I am hugely aware that this is not the way it is for all women, and after only 1hr and 10 minutes I decided (thinking that I probably hadn't made it 3 cms and official labour yet) that I was going to ask for an epidural even though I had thought beforehand that there was no way I would. Fortunately the new and horrible pain which made me decide that was crowning, so not really an option at that point and my daughter was born after 1hr 20 mins in labour – as I say “wierdo!”
    I don't feel that I am qualified to comment on what other people should, or shouldn't do because I have no idea how it feels for them and, as you rightly point out, this is essentially an evidence free zone. It isn't that I (as a Dr) could ever say “this is the best way to do this” – I would be making a moral judgement on the woman, not actually giving evidence based advice.

    The one thing I would say, however, is that all the advance education in the world doesn't tell you what it's going to feel like, and the organisations that tend to educate women at the moment are very biased towards the “need for pain relief is weakness/only because the evil Drs have brainwashed you” camp, meaning that I feel the current level of “education” probably leaves women more likely to come out of an assisted/painful labour feeling as though they have failed rather than less.


  4. I find this all rather fascinating.

    As a woman who hasn’t given birth I’ve got absolutely nothing to add to that end of the discussion, but I’m in quite a lot of pain quite a lot of the time, so I think I’ve got a different perspective on pain relief. I would say that there is a general feeling (not just relating to childbirth) that taking any form of medical pain relief is some sort of failure, or wimping out – I’m not talking about the odd paracetamol for a headache or something, but more on going. I have the same conversation with the pharmacy team in Boots about why I take the strength of tablets I do every time I get a repeat prescription – I think the least helpful was when one of the locum pharmacists suggested I perhaps try either paracetamol or ibruprofen as an alternative. Given that I take one of the strongest available opiate based painkillers PLUS paracetamol whilst smothering myself in ibruprofen gel at the same time and it doesn’t really help that much – just lets me function – it was unhelpful in the extreme. If I could manage without taking the tablets that make me feel fuzzy, sick, generally incapable of anything that requires concentration and has a world of other side effects which I then end up taking more things for – I really would be trying – a similar point to yours in childbirth: if you could manage without then you would – if you can’t then why be made to feel worse emotionally than you already do physically? Being made to feel bad about something you’re not in control of is deeply unhelpful.

    There’s been some interesting research done into why different people feel pain differently which suggests that your body can get it’s neurotransitters in a pickle and so you can feel either more or less pain from the same sensory input dependant on how you are wired – and even the same sensation at different times can feel different within the same person, let alone person to person (see here for a much better explanation!). It baffles me that given that so many people are in chronic pain constantly that more research hasn’t been done in general into pain relief – let alone during childbirth. I think a more holistic and broad minded approach to the entire process of both pain relief and labour/pregnancy seems to be needed – there is a growing feeling that people are treated as a distinct and independent set of symptoms rather than a person with interconnected issues.


  5. Hi, thanks for the comment,

    I tend to agree on the biased education point, I'm not sure what it is like in other parts of the country etc. but I got a very anti-pain relief, anti-doctor message especially from my NCT classes, really not the helpful unbiased information I was hoping for.


  6. Hello Helen!

    I deliberately steered away from talking about chronic pain in this post as I'm fortunate enough to have little personal experience of it and I don't think I could have done justice to the many complicated issues involved (and this blog is focused on parenting issues more. But I agree that the same points apply when it comes to not making people feel guilty for taking pain relief and the need for far more research into both the biological and psychological causes (and the interaction of the two). In the case of chronic pain especially I think there is also a need for the general public, doctors and in many cases patients to be educated that if a condition is partially or even completely psychological it is still “real” and can still cause genuine pain, unfortunately I think both medicine and society are a long way from that.


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