Can anyone name this movie?

I'm trying to think of the name for this movie, but can't think for
the life of me!

It's an Australian film, about a group of pregnant women, who are
kidnapped, and had their babies cut of out them. Each woman has a
coloured key implanted inside of them, which correspnds to which baby
is theirs. The story is a fight for survival, and a 'last one
standing', has their baby given to a family.