Prevalence of Small Intestinal Bacterial Overgrowth (SIBO) in Women With Endometriosis

This is a prospective, single-arm observational diagnostic study without therapeutic intervention or control arm. Participants undergo diagnostic assessment for SIBO including lactulose hydrogen/methane breath testing and gastroduodenoscopy with collection of small intestinal luminal aspirate, mucus and mucosal biopsies, as well as stool, saliva and venous blood sampling. Gastroduodenoscopy is performed only when clinically indicated and is not performed solely for study purposes. During the clinically indicated endoscopic procedure, two additional mucosal biopsies are obtained for study-specific analyses.

Inclusion Criteria: * Informed Consent as documented by signature * Age 18 or older * Premenopausal status (menopause is defined as amenorrhea lasting one year or longer) * Diagnosis of endometriosis (Ziwig Endotest® or histologically confirmed) Exclusion Criteria: * Pregnant (positive β-HCG in the blood) or breastfeeding women Inability to follow the procedures of the study (due to language problems, psychological disorders, dementia) * Presence of medical conditions contraindicating a saliva test * Diagnosis of another gastrointestinal major diagnosis * Presence of any condition known to associate with/ increase risk for SIBO (other than endometriosis) namely 1. Scleroderma, diabetic neuropathy, amyloidosis, post-vagotomy, morbid obesity , non-alcoholic fatty liver disease, liver cirrhosis, cystic fibrosis, irritable bowel syndrome, altered intestinal anatomy such as diverticula. 2. Patients with intake of medicaments known to inhibit motility or gastric acid secretion 3. Patients with choledocholithiasis or malignancy within the biliary tree or at the ampullary region obstructing biliary outflow