To be fair, labour and birth is just one aspect of classes.
I did two rounds of NCT courses as a participant and we did baby care, pregnancy anatomy (what's normal and what's not) and we spent a lot of time talking about relationship changes, how to fit a baby into life and a little on feeding choices.
There's an awful lot to cover in those eight (or whatever) sessions.
We also did relaxation every week (which is good for training your mind to be able to relax) and practised breathing exercises which again is quite useful, no matter what kind of birth you have.
We did re-enact a caesarean and we did learn what ventouse, forceps etc. were and briefly what sorts of pain relief are available.
I plan on taking a similar tack in my own classes, but focussing heavily on birth choices - getting yourself the care providers and support team you need and learning about informed consent (which often falls by the wayside in the US). I honestly don't plan to spend a lot of time talking about medical interventions - I'm not convinced women think it will happen to them so if they're not interested, they tune out anyway, and I'm quite honest about the fact I am encouraging natural birth (people are quite welcome to take one of the copious hospital courses if they want a medicalised approach). That said, I will cover the basics and have handouts available.
I think the most valuable thing I can give as an educator in the parts of the class that are about preparation for birth are the tools (like breathing, relaxation, how to use a birth ball etc.) and the information (what IC is, your rights, doulas, building a good support team). While I can touch on medical interventions, I'm not going to dedicate more than one class to them.
I'm quite honestly not going to be able to spend a class on things that can go wrong. It's just unworkable and would leave a very depressed, pessimistic group. Because what good does it do? I can teach women how to maximise their chances of something NOT going wrong. I can teach them some coping techniques for what to do if things DO go wrong (and techniques like BRAIN for assessing benefits/risks/alternatives etc.) if interventions are suggested and I can give them lists of places to go to get help should they be affected by stillbirth, birth trauma etc. etc.. But it doesn't help anyone to say, "Oh, by the way, you might bleed to death after the birth."
I'm genuinely interested here though - if you think negative outcomes, how do you think those should be approached in class? From my experience, we had a stillbirth in our NCT class (the first of us to give birth ) and the teacher was wonderful. She spent a lot of time talking it over with us, our fears and what we could do to help our fellow group member. I think this sort of reactive approach was much more helpful.
The problem for antenatal teachers is that the class time is SO limited. We're talking about something like 14 hours (not counting coffee breaks, relaxation practice etc.) to split between everything from relationships to feeding choices. It's a matter of prioritisation and giving women what is most useful.