Yes - nipples! Apparently they get bigger and darker in pregnancy. They certainly did with my first pregnancy and whilst they are no longer that dark, they never did get smaller! hehe
I keep waiting for them to get darker but I think they didn't until the third trimester with my first pregnancy. So far, I seem to just have a dark ring around my nipples - which looks terribly attractive...not! Though it is kinda funny!
Whats that all about then? Well apparently is had to do with hormone changes in pregnancy - thats just what they do! Makes it easier for baby to find source of food as well when baby is born due to their poor eyesight.