Anogenital injury following sexual assault and consensual sexual intercourse: a systematic review and meta-analysis

Abstract

Background: Sexual violence is a grave human rights violation and a serious global public health challenge. Rates of reporting of sexual violence and subsequent passage of cases through the criminal justice system are poor all over the world. The presence or absence of anogenital injury following sexual assault may influence survivors in their willingness to report a crime, and law enforcement officers and jurors in their decision making regarding the laying of charges and/or conviction of offenders. The aim of this systematic review was to compare rates of identification of anogenital injury (AGI) in women following sexual assault and consensual sexual intercourse using the same examination techniques.

Methods: In this systematic review and meta-analysis, Medline, Embase and Google Scholar were searched for relevant studies (in any language, with no age or sex criteria) published between February 25, 1993, and February 25, 2023, that directly compared AGI between individuals after either sexual assault or consensual sexual intercourse. Abstracts, conference proceedings, and case reports were excluded. The primary outcome of interest was any form of detected AGI. The Mantel-Haenszel method was used for meta-analysis using random effects modelling to determine the risk ratio (RR) of AGI between sexual assault and consensual sexual intercourse. Quality assessment was undertaken using the Newcastle-Ottawa scale tool. The I² statistic was used to determine heterogeneity among studies. An I² >75% was considered high heterogeneity. Funnel plots were used to assess the risk of publication bias, by determining any visually apparent asymmetry. This analysis is registered with PROSPERO, CRD42023402468.

Findings: We included 10 studies, accounting for 3165 study participants. All participants were female. AGI was detected in 901 (48%) of 1874 participants following sexual assault and 394 (31%) of 1291 participants following consensual sexual intercourse. Meta-analysis of all included studies demonstrated that the presence of AGI was significantly more likely for participants following sexual assault than consensual sexual intercourse (RR 1.59 (95% CI 1.21, 2.09); p < 0.001). There was a significant heterogeneity among studies and funnel plots suggest that this RR may be an over-estimation. Subgroup analysis including only high-quality studies showed no significant difference between groups.

Interpretation: Although AGI was significantly more likely to be detected after sexual assault than consensual sexual intercourse, more than half of survivors of sexual assault have no detectable injuries. The presence of AGI, therefore, does not prove there has been sexual violence and absence of injury does not refute that sexual assault has occurred.

Funding: The University of Birmingham.

Keywords: Anogenital injury; Forensic; Non-consensual; Rape; Sexual assault.

Fig. 1

PRISMA flow diagram for the identification, screening and inclusion of studies.

Fig. 2

Forest plot showing the risk ratios for anogenital injury following sexual assault (non-consensual) vs consensual sexual intercourse.

Fig. 3

Euler diagram illustrating the numbers of study participants who were either sexual assault survivors or had consensual sexual intercourse, and whether they had anogenital injuries on examination.

Supplementary Fig. 1

Funnel plot of included studies, demonstrating the likely presence of publication bias due to asymmetry.

Supplementary Fig. 2

Forest plot showing the risk ratios for anogenital injury following sexual assault (non-consensual) vs consensual sexual intercourse for the subgroup that was deemed “good” according to Newcastle–Ottawa scores.