Allen-Masters syndrome: do the classic risk factors also apply in patients with endometriosis?

To evaluate whether the classic risk factors for Allen-Masters syndrome, such as body mass index (BMI) and spontaneous births, are in fact responsible for the condition in patients with endometriosis.

A total of 26 women who underwent a laparoscopic procedure due to chronic pelvic pain, Allen-Masters syndrome and endometriosis from 2009-2011 were enrolled in this study from an endometriosis competence center specializing in minimally invasive surgery. This was a retrospective cohort study (Canadian Task Force classification II-2).

Only eight of the 26 patients (30.77%; 95% confidence interval [CI], 14.33-51.79%) had the classic risk factors (BMI >25 kg/m(2) and/or at least one spontaneous birth). The mean age in the study group was 32.08 years (SD ± 5.45). The patients had a mean BMI (kg/m(2) ) of 19.61 (SD ± 3.07). The means for the patients' clinical data were 0.88 (SD ± 1.53) pregnancies, 0.81 (SD ± 1.23) for parity, 0.27 (SD ± 0.60) for cesareans and 0.54 (SD ± 0.99) for spontaneous births. The revised American Society for Reproductive Medicine (rASRM) stage showed a median of grade III. The left side of the posterior compartment was more often affected (73.1% of cases) than the right side in all patients.

In all, 69.23% of the cases (95% CI, 48.21-85.67%) were not explained by the classic risk factors. In view of the absence of other diseases and otherwise unremarkable parameters, we consider mechanical damage of the lesser pelvis not to be solely responsible for AMS. Further observations in patients with AMS, with and without endometriosis, may be able to contribute to research into the actual etiology of the condition.