I did prenatal yoga every week during pregnancy from about 3 months until a few days before DD was born. I'd only done a few classes of yoga in the past, so wasn't really sure if it was my 'thing'. However, I loved it. During pregnancy it was great for relaxing, and having an hour timeout from work to think about my body and baby was lovely - I looked forward to it each week. Some of the gentle stretches really helped with my hip and leg pains. The instructor (who was lovely!) also gave good tips on what movements, breathing, etc could be useful during labour - and as it was repeated each week, I found that I could remember it during the labour.
My partner and I also did an partners "Active birth" yoga class one weekend before the birth, and I think that was v useful as it taught him some of the moves and gave tips on what he could do, so he had some idea of what to expect when we got in the labour ward. I was surprised how much he got into he class actually!!
I ended up having an emergency c-section so didn't get to try it during the pushing stage though, so not sure if it would have helped then...
I also found the breathing techniques useful after birth when home with bubba, and trying to relax to go to sleep after the night feeds.
I'd def recommend