Evaluation of the Analgesic Effect of Intramyometrial Botulinum Toxin Injection Via Hysteroscopy in Severe Primary Dysmenorrhea

Inclusion Criteria:

• Adult women who are not menopausal,

• Experiencing severe dysmenorrhea, defined as an average pain intensity score ≥ 6/10on a Numerical Rating Scale (NRS) over the past 3 months at the inclusion visit,

• Having failed optimal first-line medical treatment combining hormonal therapy andappropriate analgesics (Level I and II analgesics, and NSAIDs),

• Having undergone a pelvic MRI within 6 months prior to the inclusion visit thatshows no evidence of deep infiltrating endometriosis or endometrioma, followingsystematic review by radiologists from the expert center managing the patient (ifthe pelvic MRI is deemed of insufficient quality for interpretation, a new MRI willbe performed at the center),

• Using a highly effective method of contraception (failure rate <1%) for the entireduration of the follow-up period. Highly effective contraception methods are definedas one of the following: combined hormonal contraception (containing estrogen andprogestin) with ovulation inhibition (oral, vaginal, or transdermal), progestin-onlyhormonal contraception with ovulation inhibition (oral, injectable, or implantable),intrauterine device (IUD), intrauterine hormonal system (IUS), condoms, bilateraltubal occlusion, vasectomized partner, or sexual abstinence,

• Having a negative urine pregnancy test on the day of the procedure,

• Having signed the informed consent form for the study at the M-1 visit.

Exclusion Criteria:

• Pregnant or planning a pregnancy during the entire study period,

• Currently breastfeeding,

• Refusal to use effective contraception during the study and for 6 months after itscompletion,

• Contraindications to botulinum toxin, including:

• Generalized disorders of muscular activity (e.g., myasthenia gravis, Lambert-Eatonsyndrome),

• Ongoing treatment with aminoglycosides, peripheral muscle relaxants, oramino-4-quinolines,

• Hypersensitivity to the active substance, human albumin, or sucrose,

• Bleeding disorders or current treatment with anticoagulants,

• Ongoing vaginal or upper genital tract infection,

• Participation in another interventional clinical trial,

• Inability to cooperate or understand the study requirements in a way that wouldallow strict adherence to the protocol,

• Subject to legal protection measures (e.g., guardianship, curatorship, or judicialprotection),

• Not affiliated with the French social security system,

• Unable to access the internet to complete questionnaires at Month 1 and Month 6.