Bleeding gums at night in bed may be related to periodontal diseases, blood diseases, tumors and other reasons. 1. Periodontal diseases: such as chronic inflammation of the gums, due to the local inflammatory reaction leading to capillary dilation, blood seepage may occur. 2. Blood diseases: if you suffer from acute leukemia, which is often accompanied by blood clotting dysfunction, you may experience bleeding gums at night while sleeping. 3. Tumor: if suffering from gum cancer, when the cancerous tumor invades the blood vessels, bleeding gums may appear. It is suggested that people with bleeding gums at night should go to regular hospitals for consultation in time, so as to clarify the cause of the disease and carry out standardized treatment under the guidance of doctors, so as not to bring adverse effects to the body due to delayed condition.