The perpetration of IPV by men against women is widespread: between 15% and 71% of ever-partnered women in 15 countries reported having been exposed to physical or sexual IPV or both, in their lifetime and 4–54% reported being exposed in the past year [3]. The prevalence of emotional IPV determined in various studies ranges between 9% and 70% [4]. In most settings, women are at far higher risk of violence from an intimate partner than from any other type of perpetrator [3]. In Sub-Saharan Africa, where the burden of HIV is highest, the prevalence of physical and sexual IPV was also highest, ranging from 35.9% to 70.9% [3]. There are some indications that women might under-report IPV. Studies of male perpetration in South Africa have found women’s reports of victimization to be lower than what one would expect given men’s reports of the extent to which they perpetrate IPV [5, 6]. There is increasing awareness that IPV perpetration and victimization start in early adolescence. In a Sub-Saharan African study amongst young adolescents, 13–38% of the women reported being victims [7]. Between 8% and 57% of adolescent women in the United States reported being victims of IPV [8].

Women who are exposed to IPV are at a higher risk of incident HIV infection, and this has been demonstrated in three prospective studies [9–11]. One of these studies found that the association was present for different types of IPV, and was stronger for more severe forms of violence compared with the less severe and for more frequent exposure to violence compared with the less frequent [11].

There are various ways in which IPV and gendered relationship power inequities increase women’s risk of HIV infection [9, 12–14]. Women in violent or inequitable relationships have limited ability to assert their choices about sexuality and how to protect themselves from HIV. The physical injuries that are a consequence of sexual violence put women at increased risk of HIV if their partner is positive. There is evidence that men who perpetrate IPV are more likely than non-perpetrators to be infected with HIV [6] and to engage in a cluster of sexual risk behaviours, linked to an ideology of successful masculinity [6]. The psychological consequences of IPV may lead to impaired decision making, which might increase women’s risk behaviour [12]. And finally, it has been proposed that women’s exposure to IPV compromises the immune response in relation to HIV infection [12].

For women, the acquisition of HIV after rape is of concern, particularly in Sub-Saharan African settings where HIV prevalence is high [15] and rape is prevalent. For example, 30% of men in South Africa reported ever having raped a woman [6], and the incidence of rape amongst young men was 11% per 100 person years in another study [16]. There is, as yet, no evidence that men who rape are more likely than those who do not to be HIV positive [6]. Rape clearly impacts on HIV acquisition in the short term through the act of rape but also in less direct ways. For example, the trauma and fear that result from rape have been shown to be a barrier to the completion of post-exposure prophylaxis (PEP) regimens amongst survivors who are HIV negative. In a study amongst South African women, only one in three women who had been raped completed their PEP regimen [17]. It is very likely that the impact of rape on HIV acquisition lasts into the medium and long term; however, there are no longitudinal studies to elucidate this.

For women living with HIV, it is possible that IPV and sexual violence undermine their HIV care and treatment, but this has not been well studied. We know that fear of disclosure is a barrier to adherence to HAART [18] and that concerns about IPV are barriers to disclosure [19].