I have large fibroids in my uterus (5 month pregnant) and c-section will be performed. Will it be painful?

I went to see the gyc. and she said that she will not touch the fibroids during C-section. If she does what are the chances of Hysterectomy (removal of uterus) ? I am scared as it is my first pregnancy and I need more kids. Will these fibroids decrease in size by themselves or I need the treatment after pregnency?