Genital Findings in Prepubertal Girls: What Can Be Concluded from an Examination?

Abstract

Introduction

Interpretation of genital findings is a key component of the medical examination for suspected child sexual abuse. This study seeks to review the extent of evidence-based research on genital findings in prepubertal girls.

Methods

Literature review on normal genital anatomy in non-abused girls, case control studies comparing abused and non-abused girls, and observations of healing where the mechanism of injury is documented.

Results

A prolific literature exists on children examined for suspected abuse. By comparison there is a very little literature on children screened for non-abuse. Primary data on normal genital anatomy in girls after the neonatal period was found in 10 papers of non-abused girls and 6 case-control studies. The screening methods used to ensure that only non-abused children were assigned to non-abused groups were of variable standards. The evidence base on prepubertal girls selected for non-abuse using robust methodology is very small. The evidence base on healing of documented genital injury is contained in two case series, and a small number of case reports. Almost the entire evidence base on prepubertal genital anatomy in girls is derived from the USA.

Conclusions

Knowledge of the American studies and the limited extent of the total evidence base are essential to interpretation. A posterior rim of hymen measuring at least 1 mm is always present unless there has been trauma. There is such a wide range of normal hymen orifice size, that measurements are generally unhelpful. Genital injuries generally heal rapidly and most heal without residua. Hymen healing does not leave scarring, but scarring or vascular changes may occur to surrounding tissues. Except for deep lacerations hymen injury leaves no evidence of trauma. A full thickness transection through the posterior hymen is reliable evidence of trauma and does not heal without surgical repair.

Introduction

Since the early 1980s, doctors have been examining children for evidence where there is a suspicion of sexual abuse. In girls this often entailed looking for features in the hymen such as tears or scarring or estimating the hymen measurements.¹ Physical findings were the hallmarks of physical abuse and neglect and so it was expected that with sexual abuse there would also be abnormal findings. High rates were reported in children examined in the UK.2, 3, 4 Many of these were findings that currently would be accepted as normal or non-specific.⁵ Around the same time pediatricians in the USA commented that “experience with cases of possible sexual abuse has taught us that much work still needs to be done in understanding normal prepubertal female anatomy and interpreting findings in sexual abuse cases.”⁶ In the USA it was recognized early on that physical signs were usually absent.⁷ This conclusion has been consistent with large series of examinations subject to blinded peer review of photodocumented findings.⁸ In acknowledgement that findings were most often normal, examination techniques were sought to improve visualization of micro trauma. These included photodocumentation with magnification, particularly with use of the colposcope. The search for micro trauma proved unhelpful; however, photodocumentation became the established medium for recording examinations. It has been standard in the USA for over 20 years. The situation is very different in the UK, where services for acute child sexual assault are seriously deficient and photodocumentation has only very recently become standard in Sexual Assault Referral Centers. It was still not available in 45% of other examination venues surveyed in 2005.⁹

Despite deficiencies in documentation, definitive medical statements about ‘abnormal’ genital findings are common in cases proceeding through the UK court system.¹⁰ Physical findings, when identified, have a powerful influence on any court process. It is as true now as in the 1980s that research describing the genitalia of children carefully selected for non-abuse provides essential information to assist interpretation of these examinations. In view of the high rate of diagnostic or supportive findings reported in cases reaching the UK courts, it is timely to review the literature on genital anatomy in prepubertal girls.

A review of the literature on the subjects of normal genital anatomy in prepubertal girls, healing of genital injuries in prepubertal girls, and the medical diagnosis of child sexual abuse was performed using the following resources:

MEDLINE (PubMed) 1950 to date

EMBASE 1974 to date

CINAHL 1982 to date

SCOPUS 1900 to date

Subject headings used were normal prepubertal genital anatomy, prepubertal genital examination, hymen examination, child sexual abuse, pediatric/child and forensic genital examination, pediatric/child genital/hymen injury. The Cochrane Library was not helpful, because randomized trials are not relevant to this area of medical practice. There was no attempt to search the ‘gray literature’ (conferences, abstracts, theses, and unpublished papers). A preliminary scrutiny of titles and abstracts was undertaken and full papers were obtained and reviewed if the paper in question addressed issues relevant to the topic.

Articles that did not address the relevant topic and studies that did not report relevant outcomes were excluded. Papers were hand searched for additional titles that did not appear in the database searches. The non-English literature is difficult to review, not only because of translation difficulties, but also because the descriptive terminology used for the hymen is not necessarily directly comparable to accepted terminology used in the English-language literature. Papers included are only those in English.

Papers specifically detailing anal rather than genital anatomy are not considered here. Papers documenting only newborn hymen data have been excluded from the tables, because the possibility of sexual abuse is generally an issue arising after the neonatal period.

However, they are included in the text where the relevance of newborn data is discussed.

Papers included are:

• Primary data on genital findings in non-abused prepubertal girls (Tanner stage 1) after the newborn period

• Case control studies comparing non-abused girls with girls believed to have been abused

• Papers documenting healing of genital injuries in prepubertal girls.

Where more than one paper may include data on the same normative/control children this has been noted. Papers were evaluated for study design and for reported genital findings, with particular attention to the method by which children were assigned to a ‘non-abused’ or ‘low risk’ classification.