45 years old sex with blood, if for women may be related to cervicitis or cervical cancer, etc., men may be related to seminal vesiculitis or percutaneous glands, etc.. 1. Women have blood in sex life: (1) Cervicitis: when inflammation occurs in the cervix, if there are symptoms, it may be manifested as increase in vaginal secretion, vulvar itching or discomfort due to the stimulation of secretion, or bleeding after sexual intercourse. (2) Cervical cancer: Vaginal bleeding often manifests as contact bleeding, i.e. vaginal bleeding after sexual intercourse or gynecological examination. 2. Blood after sexual intercourse in men: (1) Vesiculitis: urogenital tract infection and unclean sex can cause its occurrence, which can cause symptoms of urinary tract irritation, pain in scrotum and perineum, and also hematospermia during sex, in which semen is red or with blood clots. (2) Foreskin glansitis: it can be caused by pathogen infection, redness, swelling, pain at the foreskin and glans, and bleeding in severe cases. Bleeding after sex may have other reasons, it is recommended to visit a hospital specialist in time for examination and treatment after a clear diagnosis.