Gums bleed when pressed may be caused by periodontitis, pregnancy gingivitis, leukemia gingival lesions, etc., as follows. 1. Periodontitis: the gums may bleed when eating or brushing, and with the development of the disease, the gums may bleed spontaneously. 2. Gingivitis during pregnancy: during pregnancy, due to elevated levels of female hormones, the original chronic inflammation of the gums increases, resulting in swelling of the gums, easy to bleed when eating or sucking, and easy to bleed when lightly touched. 3. Leukemia gingival lesions: swollen gums, obvious bleeding tendency, gingival margins often have blood oozing, and not easy to stop. Gums bleeding when pressed may have other reasons, it is recommended to go to the hospital in time, clear cause for targeted treatment.