Hi and thanks for all the fantastic and thoughtful replies.
I should perhaps have made this clear in the OP, I do know that there is more to birth than the bit at the end where you get drugs and push the baby out. I'm 40 next year and throughout my life I have had friends who are mothers and who have shared their birth experiences with me so not a complete innocent! I should probably also have said (but didn't for reasons of space) that I am expecting to use all the breathing and relaxation techniques at my disposal to get me through early stage labour, and hope to spend as much time as possible dilating slowly and calmly at home, in my bath/on my Swiss ball/walking about my flat with DH, before I turn up at the Homerton.
I've been unlucky enough to live through 2 life-threatening extreme situations as an adult and in both cases, it was having done some yoga and learned a bit about how to control my panic and pain through breathwork that allowed me to survive (without benefit of doctors or pain relief I should add but long story and not the place here).
I'm therefore fairly sure I could survive a so-called 'natural birth' (I really dislike that term, think 'vaginal birth without pain relief' is more accurate.)
But I don't think I would thrive. I'm fairly sure, knowing me, that the unmanaged pain - for hours - would get in the way of me being able to labour mindfully and breathe properly and stay in a non-panicky-place. I think pain management would help me remain more 'present' and focused and dare I say it - relaxed. And I think that's more important for me and the baby than anything else. I think if the effects of pain management drugs were so awful for mothers and babies there would be litigation about it. Yes, there are risks. I think managing extreme pain has benefits that outweigh the risks.
I also think it is pretty damn unrealistic not to expect extreme exhaustion and extreme pain in a first labour at age 39. So I am therefore sure that I want pain relief, not just nitrous oxide, which does shag-all for me (yes, I've had it recreationally before) and I want as much information and knowledge as I can get to be (awful phrase) as empowered as possible.
Which brings me on to the oft-repeated stuff like You're also more likely to be happy with your care and less likely to experience postnatal depression if you give birth at home or in a MLU. Isn't this a case of massaging the stats interpreting the data?
Because, let's face it, the stats re. births at home/with fewer interventions are largely going to be the less-complicated ones, aren't they? Stands to reason if you've had a labour which didn't require much in the way of medical intervention, (baby wasn't breech, maybe it was your second labour, it was a shorter labour, you'd previously established that your body could cope) then of course your recovery is going to be easier. You dodged a bullet.
I'd be happier if my dentist only had to give me a filling rather than root canal work!
But just look at the numbers of first timers who end up using drugs, despite their plans. It's more realistic to assume that I, and probably most of the women in an ante natal class will use pain relief, and several of us will have surgery or interventions. It's realistic to assume it, rather than assume a birth without pain relief. And I don't think it is unnatural to want help and pain relief!
The first feminists fought for pain relief for labouring women, after all.
This post has gone on and on, sorry.
My original concern was whether, knowing this - knowing myself - and being this realistic from the start would put me on a collision course with an organisation that has a rep for having a 'natural birth' agenda, but which also has a rep for being a good way to meet other local parents to be. It seems it depends largely on who teaches the course and is pot luck (about how much of an anti-intervention bent the course has). I do want to meet other parents. I don't want to waste 200 GBP plus on having my birth plan choices disrespected by the teacher. I'm happy to learn as much as possible about managing pain - as long as the fact that I want and expect to CHOOSE to use pain relief for the final push - is validated.
I promise I will never write such a long post again!