Mushy's last kitten was born tail first, and it hurt her a bit as she yowled only for that one... so I don't know that it's a huge issue unless you can only see baby's tail for a certain amount of time... I'm not expert though.
Nope, about half the kittens will be born tail first. Its a little harder on mom/kitten, especially if its the first one; but no real concern. Now if she's in heavy labor and the kitten is tail first and not coming out right - then you have problems.
