I'm a 37 year old female weighing 112 lbs. and 5'5". I am very healthy and thin because I am a runner and genetically built that way. I eat an extremely healthy diet and have no medical history to mention. I was taking a shower tonight and looked down and noticed my left nipple was bleeding. It was on the side, not directly in the center where milk would come out. I had a razor in my hand and just finished shaving under the opposite arm. I'm wondering if i accidently nicked myself and didn't feel it. It stopped bleeding after about 5 minutes, and it will not bleed now even when I squeeze it. Is that a good sign? I have no breast lumps, etc. I have done a thorough breast exam and been examed by a doctor recently.