Eh, sayang, this one kena check with your doctor or midwife urgently, don't wait, go today or to the hospital if it's weekend, okay? Blood from the nipple at 39 weeks needs proper checking, bukan benda boleh tunggu-tunggu. A few of us moms had different things happen during late pregnancy, but honestly, you really need someone to examine you properly, could be so many things, and at this stage you want to be safe. Don't worry yourself too much, but do get it checked out today lah. Let me know how it goes, okay?