Endometriosis is a systemic, steroid-dependent, inflammatory disease characterized by the growth of endometrial-like tissue outside the uterus, affecting approximately 10 % of women of childbearing age. The etiology and pathophysiology of endometriosis is not completely understood to support effective treatment and prevention strategies. Despite the steroid dependency, little is known concerning the underlying metabolism of estrogen and other tightly related steroids. Moreover, shortening the long diagnostic delays is a major priority in endometriosis research.

The main aim of the study will be to develop a global steroidomics analytical strategy " fit-for-purpose" to improve the knowledge of endometriosis pathophysiology and boost the identification of diagnostic biomarkers.

Therefore, in a first step, a new analytical method will be developed adapting state-of-the-art liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS) approaches for steroids and its metabolites towards endometriosis research. The investigators will ensure the characterization of established steroids and its metabolites known to be relevant to endometriosis, but also expand the panel with non-targeted methods to identify phase-1 and -2 metabolites potentially informing of novel steroidogenic pathways in serum and urine.

In a second phase, a case-control study will be conducted to apply the strategy in a sample of women with and without endometriosis. In a third step, the investigators will explore statistical differences in steroid profiles among endometriosis groups and evaluate the discriminative performance.

The proposed method has large applications in endometriosis research and large potential to provide novel clues about the still poorly understood steroid metabolism disruption undergoing in endometriosis. Ultimately, non-invasive biomarker discovery in urine could revolutionize endometriosis diagnosis and management, allowing for earlier detection and personalized treatment strategies, ultimately improving the lives of individuals affected by this often overlooked but debilitating condition.

In parallel, the role of dysbiosis of the vaginal microbiota on hormonal alterations linked to endometriosis will be studied.

Inclusion Criteria:

• Women aged 18 to 45
• Free, informed and written consent from the patient to participate in the study
• Good understanding of the French language
• Patient affiliated to or benefiting from a social security or similar scheme

Specific inclusion criteria for each group:

Group 1. Controls.

• Women with no laparoscopically confirmed signs suggestive of deep endometriosis.
• No clinico-biological criteria in favour of a diagnosis of endometriotic disease, nor any radiological signs (ultrasound or MRI) suggestive of endometriosis.

Group 2. Cases of deep endometriosis.

• Newly diagnosed women (less than 12 months).
• Severe, deep endometriotic pathology with surgical indication (clinical examination, imaging tests, pre-operative findings).

Exclusion Criteria:

• Intercurrent diagnosis of pregnancy.
• Presence of other hormone-dependent pathologies (e.g. breast cancer, PCOS).
• Acute infection.

The STERONLINE study population will be made up of women aged between 18 years and 45 years

• 45 patients with endometrioma
• 45 patients without endometrioma