HIV is spread through the blood, pre-seminal fluids, semen, vaginal fluids, rectal fluids, or breast milk of a person who has HIV.In the United States, the main risk factors for HIV transmission are the following:Having anal or vaginal sex with a person who has HIV without using a condom or taking medicines to prevent or treat HIV,Sharing injection drug equipment (works), such as needles, with a person who has HIV,Several factors can increase the risk of HIV in women. For example, during vaginal or anal sex, a woman has a greater risk for getting HIV because, in general, receptive sex is riskier than insertive sex. Age-related thinning and dryness of the vagina may also increase the risk of HIV in older women. A woman's risk of HIV can also increase if her partner engages in high-risk behaviors, such as injection drug use or having sex with other partners without using condoms.