I'm wondering how soon after sex can implantation bleeding occur. My SO and I had unprotected sex (no condom, just the pill) on Friday Saturday and Sunday. Then Tuesday (3-5 days later) I noticed a small tinge of pinkish red bleeding on the tp when I wiped. This bleeding increased slightly to stain my underwear with a patch the size of a 50cent piece but was still only just visible on the tp. I put in my diva cup and when I took it out and wiped it there was slight pinky milky blood around the rim but that's it. The bleeding was gone after about 6 hours later.