- Categories 3 and / or 4 for the use of LNG-IUD according to the medical eligibility criteria of the World Health Organization (WHO), users of illicit drugs and / or alcohol, allergy or contraindication to lidocaine, presence of chronic pelvic pain of any etiology, presence of cervical abnormality such as isthmus-cervical fibrosis or incompetence, surgery on the cervix, psychiatric disorders, chronic use of medications that could interfere with the pain threshold (such as antidepressants and anticonvulsants).