I deliverd the placenta naturally. I admit I got a bit fed up as I just wanted the whole thing to be over (having done the hard bit) but the midwives encouraged me and got me to lay on the bed breatfeeding and bonding with my baby and hey presto it was out! As for afterpains, I can't make a comparison of natural vs injection as this was my first but what I will say is that I did not experience any of the pain you described - all I had was a bit of discomfort from time to time as my uterus started to return to its normal size, certainly not major pain, not even as bad as period pains, i don't know - maybe I wa lucky ?!