There are three ways to transmit HIV: 1) mother-to-child transmission, 2) sexual transmission, and 3) blood transmission. Mother-to-child transmission is when a pregnant woman with AIDS does not protect her child during delivery. Sexual transmission means that during sexual intercourse, friction may lead to a slight break in the mucous membrane of the sexual organs, and the virus in semen or vaginal secretions may be transmitted to the sexual partner. Blood transmission includes not only the importation of HIV-contaminated blood or blood products, but also other blood exposures, such as sharing syringes and needles among intravenous drug users, and medical personnel getting their own skin pierced by needles or instruments while treating AIDS patients.