National Partnership for Women & Families

Monthly Women's Health Research Review

Review Assesses Effect of Intimate Partner Violence on Women's Contraceptive Use

Summary of "Estimating the Effect of Intimate Partner Violence on Women's Use of Contraception: A Systematic Review and Meta-Analysis," Maxwell et al., PLOS One, Feb. 18, 2015.

Introduction

"Understanding how IPV modifies women's ability to adopt contraception is central to designing [family planning] interventions that allow women who experience IPV to manage their fertility," as well as "to inform HIV prevention interventions," according to Lauren Maxwell of McGill University and colleagues.

The researchers aimed to "estimate the causal effect of IPV on contraceptive use" by conducting a systematic review to "buil[d] on" studies that that show "an association between IPV and different sexual health outcomes."

Methods

The researchers searched 11 biomedical databases "to identify research studies on IPV and women's [reproductive health] outcomes" conducted between Jan. 1, 1980 and Dec. 3, 2013.

The researchers first searched for "studies of women and girls of any age that evaluated the association between respondents' exposure to IPV ... and an outcome related to women's [reproductive health]." They "included all types of IPV," including "physical, sexual, psychological, or economic." Following the initial search, the researchers restricted their inclusion criteria to studies "with an outcome related to women's use of contraception."

Results

The researchers limited their analysis to 10 studies.

According to the researchers, the "[s]tudies varied in their description of IPV and in the time period over which they assessed IPV." The researchers noted that the studies "generally classif[ied] IPV into four separate categories: emotional, physical, sexual, and economic," but that all the studies "included physical violence in their exposure definition."

The researchers noted that five of the 10 studies "limited their estimate of the effect of IPV on women's contraceptive use to one or two methods, including oral contraceptives, condoms and diaphragms, and condoms." Of those studies, three also "considered withdrawal and the rhythm method as contraceptive methods," while two "limited their definition to modern methods."

Every study "adjusted for basic demographic confounders" and some "adjusted for factors thought to mediate the relationship between IPV and contraceptive use." Four studies looked at "additional [reproductive health] outcomes," such as use of hidden methods of contraception, use of emergency contraception, reports of several partners, "shortened interpartum intervals" and unprotected anal sex.

Meta-analysis

For the meta-analysis, the researchers excluded three studies that "were classified as having a high probability of bias." However, they noted that "[b]oth the studies classified as having a high probability of bias and studies classified as subject to low or moderate levels of bias indicated that IPV was associated with a decrease in women's odds of using contraception."

The researchers also found that the three studies that included both modern and "less effective" types of contraceptives "were more likely to find a non-significant association between IPV and women's use of contraception" compared with "the four studies that estimated the effect of IPV on women's use of modern contraceptive methods." Meanwhile, the three studies that looked at women's reports of their male partner's condom use found that women exposed to IPV "were significantly less likely to report that their partners used condoms than women who did not experience IPV."

The researchers wrote that the meta-analysis of all 10 studies "indicated that women who experience IPV have a lower odds of adopting contraception than women who do not experience IPV," although the "results were subject to a high level of heterogeneity." When assessing only the seven studies with low to moderate levels of bias, the researchers found that women exposed to IPV were 53% less likely to report contraceptive use than women who were not exposed to IPV.

The researchers noted that some studies classified violence based on severity while others looked at violence frequency. Among the three studies that measured IPV duration, according to the researchers, "the magnitude of the effect of IPV on women's use (or non-use) of contraception is greatest for women who experience persistent IPV."

Discussion

The researchers wrote that the meta-analysis findings "suggest that IPV affects women's use of contraception," with some evidence suggesting that there is a "relationship between duration of IPV exposure and women's contraceptive use." According to the researchers, "IPV is associated with a decrease in women's use of partner dependent methods," although the association "is likely modified by contextual factors."

The researchers identified several areas for future research, including research that:

~ Orders the timing of "of exposure and outcome [to] allow for a better understanding of the causal effect of IPV on women's use of contraception";

~ Uses a "more complete definition of IPV to better estimate the total impact of IPV on women's use of contraception";

~ Assesses "the impact of harm reduction strategies on the ability of women who experience IPV to use condoms with their male partners";

~ Examines whether women who experience IPV would "prefer to adopt long-acting reversible and permanent contraceptive methods that are less likely to require their partner's involvement";

~ Limits its assessment on the effect of IPV "to modern methods of contraception" and "differentiate[s] between methods that do and do not require ongoing negotiations between a woman and her male partner"; and

~ Examines the "importance of IPV duration in predicting women's use of contraception."

The researchers added that "HIV prevention interventions should consider addressing IPV," given that their review found that woman who reported IPV also indicated they were less likely to use condoms.