ActiTENS Mini (Transcutaneous Electrical Stimulation) in Women With Chronic Pain From Pelvic Endometriosis

Inclusion Criteria: * Women over 18 years old * Followed-up in gynecology consultation for endometriosis confirmed by specific imaging (MRI or ultrasound) * Referred to a gynecological or a pain center * With chronic pelvic pain (for at least 3 months) related to endometriosis, pelvic pain being the predominant symptom of endometriosis: pelvic pain present at least 15 days per month in the previous 3 months * Stable and optimal analgesic and hormonal treatments during the last 3 months: any modification of pharmacological treatment in the last 3 months * Pelvic pain of moderate to severe intensity or greater than or equal to 4 on an NRS of 0-10 on average during the 8 days preceding the inclusion visit and during the inclusion visit. * Informed about the concept and accepting the use of TENS as a device, a non-drug analgesic treatment. * Able to understand the use of TENS * Having a personal smartphone enabling the EndoTENS application to be downloaded * All women of childbearing potential (WOCBP) must agree to maintain highly effective contraception by practicing abstinence or by using an effective method of birth control from the date of consent through the end of the study: Combined (estrogen and progestogen containing) hormonal contraception associated with inhibition of ovulation (Oral, Intravaginal, Transdermal); Progestogen-only hormonal contraception associated with inhibition of ovulation (Oral, Injectable, Implantable); Intrauterine device (IUD); Intrauterine hormone-releasing system (IUS); Bilateral tubal occlusion; Vasectomized partner, spermicide-coated condoms * Willingness and ability to attend the scheduled study visits and comply with study procedures * Affiliated to Social Security. Exclusion Criteria: * Symptoms of endometriosis other than pelvic pain, predominant over pelvic pain (pelvic pain is not the main symptom): digestive disorders, unstable bladder, dyspareunia, infertility, fibromyalgia, sciatica, low back pain… * Present or past allergy to actiTENS mini pads. * Pelvic surgery planned within the next 11 months. * Drug or non-pharmacological treatments not stabilized, which could influence the pathology studied during the last 3 months * Changed of treatments for endometriosis planned in the next 10 months. * Patient presenting an absolute contraindication to TENS: patient with epilepsy, patient with a defibrillator, a pacemaker, a cochlear implant or other implanted electronic devices, patient with cardiac disorders, patient with decreased or altered sensation or sensitivity in the area to be treated, for example patients with allodynia (pain triggered by a stimulus that is normally painless) in the area to be treated. * Patient unable to express his consent or patient in deprivation of liberty. * Patient that already used or know the functioning principles of a TENS device previously to the clinical study * Contraindications to actiTENS mini * Pregnancy and breastfeeding * Patients under guardianship or curatorship and protected adults * Patients on AME (Aide Médicale de l'Etat = State Medical Assistance) * Current participation in another research study involving a therapeutic intervention. Participation to an observational research, or a non-interventional research is allowed