Anogenital distance in adult women is a strong marker of endometriosis: results of a prospective study with laparoscopic and histological findings.

Abstract

STUDY QUESTIONCould anogenital distance (AGD) be a non-invasive marker of endometriosis and correlated to the American Society for Reproductive Medicine revised score (r-ASRM) and ENZIAN classifications?SUMMARY ANSWERSurgically and histologically proven endometriosis is associated with a short AGD in women of reproductive age but not correlated either to the severity or to the location of the disease.WHAT IS KNOWN ALREADYAGD is a marker of intrauterine androgen exposure and exposure to oestrogen-like chemicals such as phthalates. Moreover, exposure to endocrine disruptors, such as organochlorine chemicals, is associated with endometriosis. It has been suggested that a short AGD in women is associated with an increased risk of endometriosis based on clinical and ultrasound exams.STUDY DESIGN, SIZE, DURATIONA prospective cohort study was conducted from January 2018 to June 2019 in a tertiary-care centre including 168 adult women undergoing pelvic surgery.PARTICIPANTS/MATERIALS, SETTING, METHODSOf the 168 women included, 98 patients had endometriosis (endometriosis group) and 70 did not (non-endometriosis group). An operator (not the surgeon) measured the distance from the clitoral surface to the anus (AGD-AC) and from the posterior fourchette to the anus (AGD-AF) before surgery using a millimetre accuracy ruler. Endometriosis was diagnosed on exploration of the abdominopelvic cavity, and the r-ASRM and ENZIAN scores were calculated. All removed tissues underwent pathological examination.MAIN RESULTS AND THE ROLE OF CHANCEMean (±SD) AGD-AF measurements were 21.5 mm (±6.4) and 32.3 mm (±8.1), and average AGD-AC measurements were 100.9 mm (±20.6) and 83.8 mm (±12.9) in the endometriosis and non-endometriosis groups (P < 0.001), respectively. Mean AGD-AF and AGD-AC measurements were not related to r-ASRM stage (P = 0.73 and 0.80, respectively) or ENZIAN score (P = 0.62 and 0.21, respectively). AGD-AF had a better predictive value than AGD-AC for discriminating the presence of endometriosis (AUC = 0.840 (95% CI 0.782–0.898) and 0.756 (95% CI 0.684–0.828)), respectively. For AGD-AF, an optimal cut-off of 20 mm had a specificity of 0.986 (95% CI 0.923–0.999), sensitivity of 0.306 (95% CI 26.1–31.6) and positive predictive value of 0.969 (95% CI 0.826–0.998). In multivariable analysis, the diagnosis of endometriosis was the only variable independently associated with the AGD-AF (β = −9.66 mm 95% CI −12.20–−7.12), P < 0.001).LIMITATIONS, REASONS FOR CAUTIONThe sample size was relatively small with a high proportion of patients with colorectal endometriosis reflecting the activity of an expert centre. Furthermore, we did not include adolescents and the AGD-AF measurement could be particularly relevant in this population.WIDER IMPLICATIONS OF THE FINDINGSThe measurement of AGD could be a useful non-invasive tool to predict endometriosis. This could be especially relevant for adolescents and virgin women to avoid diagnostic laparoscopy and empiric treatment.STUDY FUNDING/COMPETING INTEREST(S)None.