I had a traumatic birth with DD1; very traumatic hospital transfer, but even without that I think I would have been traumatised just by the pain I experienced. I went into birth with confidence, well prepared with education and various ways of coping and so on, but it just blindsided me. DD1 was posterior and asynclitic and I was in labour for almost 24 hours, the last 15 of which were basically just one giant never-ending contraction. I couldn't cope because I wasn't getting any breaks at all to regroup and breathe, or even think.
When I got pregnant with DD2 I was soo scared of going through all of that again. Two things that I did that really helped *me* were:
1) Hire a doula - this was more to help with the fear of being mistreated by HCPs during labour as I had been with my first, but my doula also specialised in helping moms with difficult labours, malpositions etc. and had loads of tricks up her sleeve to help with that too. Just having her to talk to during my pregnancy and knowing we had come up with plans for so many different possible scenarios, and that she would be comfortable sticking up for me if need be (my DH wasn't able to do that at all with the first) was very reassuring for me.
2) Hypnobabies - really helped me to relax during my pregnancy. I was having near daily panic attacks and flashbacks due to the PTSD from my first birth, until I started doing Hypnobabies and then I rarely got that panicked after starting - made a huge difference.
I also had 'plans' in my own head for nearly every possible scenario. So, if everything was going well and I felt happy I was educated and confident enough to go for a UC (always a dream of mine), if I felt that things were going okay but I needed some more help/support/monitoring then I would call the doula/midwives and go for a HB, if the pain got to be more than I could reasonably handle I had given myself 'permission' to transfer for an epidural, etc. So, I felt like I was as prepared as could be for any possible scenario.
As it turns out I had a very nearly pain-free UC with DD2. I didn't fully realise that I was in labour until the fetal ejection reflex kicked in and she was out in just a couple of pushes after that. I credit the Hypnobabies with at least some of that, but also - it was just a different birth, different baby, different circumstances. The two labours and births could hardly have been more different - I don't think I would have believed that the same woman could have two such completely different births if I hadn't experienced it myself.
Having said that I would *still* be terrified if I got pregnant again - I got lucky once, but wouldn't want to bet on it happening again. We've decided (for this, among other reasons) that we're done with the two we have, but would definitely do the same things to prepare again if necessary. I think for me the key was to try to make the pregnancy as relaxed as possible, so that I wasn't constantly focusing on my fear - and when I did I could point to plenty of things that I was doing to manage that, and know that I had my 'plans' in place for all the different scenarios I could imagine. (Hypnobabies was very helpful for that with the fear release section - I could walk myself through potentially scary situations, allow myself to feel the fear, then set my mind to coming up with what I could do in that situation and letting go of the fear.)