Endometriosis-related infertility: ovarian endometrioma per se is not associated with presentation for infertility.

STUDY QUESTION: Is there an association between the endometriosis phenotype and presentation with infertility?

SUMMARY ANSWER: In a population of operated patients with histologically proven endometriosis, ovarian endometrioma (OMA) per se is not associated with an increased risk of presentation with infertility, while previous surgery for endometriosis was identified as a risk factor for infertility.

WHAT IS KNOWN ALREADY: The increased prevalence of endometriosis among subfertile women indicates that endometriosis impairs reproduction for reasons that are not completely understood.

STUDY DESIGN, SIZE, DURATION: This was an observational, cross-sectional study using data prospectively collected in all non-pregnant patients aged between 18 and 42 years, who were surgically explored for benign gynaecological conditions at our institution between January 2004 and March 2013. For each patient, a standardized questionnaire was completed during a face-to-face interview conducted by the surgeon during the month preceding surgery.

PARTICIPANTS/MATERIALS, SETTING, METHODS: Surgery was performed in 2208 patients, of which 2066 signed their informed consent. Of the 1059 women with a visual diagnosis of endometriosis, 870 had histologically proven endometriosis and complete treatment for their endometriotic lesions, including 307 who presented with infertility. Univariate analysis and multiple logistic regression analysis were performed to determine factors associated with infertility.

MAIN RESULTS AND THE ROLE OF CHANCE: The following variables were identified as risk factors for endometriosis-related infertility: age >32 years (odds ratio [OR] = 1.9; 95% confidence interval [CI]: 1.4-2.4), previous surgery for endometriosis (OR = 1.9; 95% CI: 1.3-2.2), as well as peritoneal superficial endometriosis (OR = 3.1; 95% CI: 1.9-4.9); Conversely, previous pregnancy was associated with a lower rate of infertility (OR = 0.7; 95% CI: 0.6-0.9 and OR = 0.6; 95% CI: 0.4-0.9, respectively). OMA is not selected as a significant risk factor for infertility.

LIMITATIONS, REASON FOR CAUTION: The selection of our study population was based on a surgical diagnosis. We cannot exclude that infertile women with OMA associated with a diminished ovarian reserve, as assessed during their infertility work-up, were referred less frequently to surgery and might therefore be underrepresented. In addition we cannot exclude that our group of infertile women present associated other causes of infertility.

WIDER IMPLICATIONS OF THE FINDINGS: Identification of risk and preventive factors of endometriosis-related infertility can help improve clinical and surgical management of endometriosis in the setting of infertility.

STUDY FUNDING/COMPETING INTERESTS: None.

TRIAL REGISTRATION NUMBER: None.