Intimate partner violence (IPV) is a human rights violation that is pervasive worldwide, and crosses all social, economic, racial, ethnic, and cultural boundaries . In a Canadian sample estimated to represent 653,000 women, 7% reported IPV of such severity that they feared for their lives, suffered serious injuries, and sought medical assistance . Women who experience IPV can suffer a variety of long term health consequences, including depression [3–5] anxiety , and physical harm [4, 7–9]. In Canada, health care costs for IPV-related injuries are estimated to be $4.2CDN billion annually . IPV that occurs during the reproductive period creates additional risks for the mother and foetus. In a representative Canadian sample (N = 6,421) of biological mothers 15 years and older who gave birth in 2006, 10.9% experienced IPV within the last 2 years, and 3.3% reported one or more occurrences during their pregnancy . IPV-related injuries result in increased reproductive health risks including placental abruption , preterm labour [5, 6, 10–13], preterm birth , antepartum haemorrhage , delivery of a low birth weight infant [10, 16], and chorioamnionitis . Pregnant women incurring kicks or blows to the abdomen from their partner are sufficiently injured to be admitted to hospital [16, 18]. However, not all women seek treatment when injured. In a US study of 3,542 women who experienced and reported IPV during the postpartum period, 77% were injured, but only 23% received medical treatment for their injuries . Women who experience IPV are more likely to be identified during health care encounters if screening occurs [7, 20, 21].
Barriers to screening for IPV in health care settings
Generally, screening for IPV is conducted in physician offices [22, 23], clinics [22–24], outpatient areas , and emergency departments [20, 22, 26–29]. In these health care settings, reported barriers to screening for IPV included (a) lack of privacy to screen [26, 30], (b) language barriers [15, 29–32], (c) cultural barriers [31, 32], (d) lack of knowledge about IPV [26, 29], (e) lack of information about screening tools, personal perceptions and feelings about domestic violence, (f) lack of time to screen [26, 29], (g) lack of instruction on how to ask questions about abuse , (h) a personal or family history of abuse , (i) not knowing what to do in the event of disclosures, and (j) fear of shocking the patient . Nurses on inpatient postpartum units are well-positioned to screen women for IPV due to the one-to-one, intimate care provided. The trust relationship developed between nurses and postpartum women can be an important precursor to women's willingness to disclose IPV . In spite of professional responsibility to screen for IPV [34, 35], screening rates are low [28, 36], suggesting that barriers exist that prevent nurses from screening for IPV. The aim of this study was to explore perceptions of barriers to screening for IPV on postpartum units in a sample of Canadian nurses.
Risk factors associated with IPV during the reproductive period
IPV is cyclical and may be misunderstood or unrecognized by the victimized woman . During the reproductive period, risk factors for IPV include minority status , young maternal age , single, separated or divorced marital status , unstable partner relationship , low education [38, 39], and low income .
Variation in rates of IPV during the reproductive period
Pregnancy may trigger higher rates of IPV for some women , while acting as a protective mechanism for others . In a representative sample of Canadian women (N = 6,421), 47% of women who were exposed to IPV during pregnancy reported a decrease in abuse, 5.4% reported an increase while the remainder reported that amount of abuse stayed the same . This finding is similar to others  who reported no increase in IPV during pregnancy. In other studies, IPV is reported to escalate during the postpartum period [19, 42–44], and for up to 33 months post delivery .
Peaks of IPV in the reproductive period vary by the type of abuse (i.e., physical, sexual, and psychological) . In a sample of low-income women, IPV victims (n = 31) and comparison participants (n = 45) reported that rates of physical abuse peaked for victims of IPV during the first 3 months of pregnancy and then declined . Rates of physical abuse were lower in the comparison group than the IPV victim group, with the highest rates occurring 12 months before pregnancy and during the 7 to 12 months after infant delivery . In both the victim and comparison groups, rates of sexual and emotional abuse were highest during the month following infant delivery . In another study, physical abuse peaked during the first 6 months of pregnancy, while sexual and psychological abuse peaked in the month after delivery . Thus, there is some indication that screening during the postpartum period may be an opportune time to identify current sexual and emotional abuse. However, emotional abuse frequently accompanies physical abuse [37, 44] and any abuse during the perinatal period was found to be predictive of later abuse . While there are inconsistencies in the literature about risk for IPV during pregnancy , it is clear that there is a substantially increased risk for IPV during portions of the reproductive period for some women.
Screening for IPV during the postpartum period may be a timely opportunity to prevent subsequent abuse and poor outcomes; yet screening rates are low [28, 36]. This suggests that there are barriers that need to be addressed to enable nurses to conduct appropriate screening. The purpose of this study was to determine (a) the frequency of screening for IPV on postpartum units, (b) the most important barriers to screening for IPV as identified by postpartum nurses, (c) the relationship between the barriers to screening for IPV and the frequency of screening for types of abuse, and (d) and to identify other factors that contribute to the frequency of screening for IPV by PPNs.