I had my nipples pierced and took them out before I got pregnant with my first. I was able to breastfeed both of my daughters...with both of the girls I had milk come out of the piercing holes lol. Didn't hurt the breastfeeding at all that baby just got a little more milk lol.
Im like 98% positive you can as long as you don't have the jewelry in cause that can hurt the babys mouth!