I don't know what you are reading but it's wrong. Yes, once you have a retained placenta you do have a slightly higher chance of having it happen again, but it is only still only a minimal risk. I had one with my 3rd birth and also had to have it manually removed under a general anaesthetic, and it was a concern with my 4th pg, but it didn't happen. There are things that you can do to reduce the chances of it happening, like delaying the cutting of the cord and letting your body's natural oxytocics do the job (although trying to get a Dr to agree to let you do this after you have already had one is like pushing poo uphill as they will tell you it is a load of rubbish, but it isn't - there is an article on the main BB site about this). But there will be a few women who have this happen with each birth, but considering that you had your first child with no problems I would say it was just a once off like it was for me.

And you don't have to have a c/section birth to avoid it either - that is quite frightening that you've read that actually. That's like saying we need to cut off your nose incase it gets blocked.