With my first pregnancy I went from a 34C to a double D! I'm a pretty petite person and I was just so unbelievably uncomfortable and miserable about growing boobs. During the whole pregnancy, I went from wearing no bra to finally wearing a sports bra to lift some of the weight off of me. But then after my daughter was born they grew a little bit more. I was more depressed than ever. Of course I breastfed, but not that long. I breastfed for about two months and then they eventually went back to a normal size.