No medic explained it to me at the time as being this enormously different experience. No women jumped forward and said "ah yes, posterior labour". And then, when I met my new (independent) midwives they asked me to talk through my previous experience. And it was like this:
hind waters going first [tick]
NHS protocol immediately starts the clock towards intervention, even though something like 90% of women will go into spontaneous labour within 96 hours [tick]
very irregular contractions to start with [tick]
very long slow progression with just a couple of centimetres dilated after 24 hours [tick]
back ache. Oh my. The back ache. And just intensified during contractions. [tick]
when waters do go (or artificially ruptured in my case) very very fast progression, made doubly intense if (like me) you are on an induction drip by that point [tick]
very long second stage(because the baby is coming out with an unexpected bit of its head first [tick]
In retrospect, I am truly astonished that I did not have that cascade of intervention leading to C-section. I imagine most first-timers with posterior labour do end up at some point on that cascade, and I was just lucky to get away with just an induced labour (avoid if you can, first timers. The contractions are intense, to say the least. Make sure they are absolutely absolutely sure your baby is getting overcooked before you allow it)
Had I known in advance that a posterior presentation might well mean an epic labour (mine was 32 hours with the induction after 24), I would have been much better prepared - to rest in the early stages, and ask for monitoring for infection rather than automatic induction. Ah well. We learn all these things first time round, yk?
Once I started actually quizzing other women, the posterior labour stories started coming out, and seems to be always long and always the back pain making things harder. Find out how to turn your babies, everyone!!!! I plan to!