Hello, Thanks for writing to us. If you are sexually active, then late conception or implantation bleeding should be ruled out through repeated home pregnancy test (after 3-4 days) or blood test for beta-hCG. Some underlying causes could be hormonal imbalance, endometriosis, old blood, endometrial tissue, hormonal imbalance, stress/ depression, vaginal/ pelvic infection etc. I suggest to consult with gynecologist for complete health check up with relevant investigation like ultrasound scan, blood count and hormone test to confirm the diagnosis. Take proper medication if required. Maintain genital hygiene. Avoid mental stress. Good luck.