Thank you for your question. This matter is to be given immediate attention as it can be cancer also. You should consult with a OB Gynecologist as soon as possible to confirm your issue. You may have to take some tests as well to rule out a chance of cancer. Another possible reason of post menopausal bleeding is atrophic vaginitis. Uterine cancer can also be a reason, by which can be got confirmed with biopsy. I hope that it will help you from getting into any more complications if done immediately.