The goal of this study is to verify whether transcutaneous stimulation of the posterior tibial nerve improves pain, quality of life and sleep deficiency in patients with pain related to their menstrual period in the short and medium-long term.

The hypothesis of the study states that by applying that method to the patients, a decrease or disappearance of pain in menstruation should happen, as well as an improvement in quality of life and sleep deficiency.

The study will consist of:

• An interview, lasting 30 minutes, in which the characteristics of the study will be explained. In case of wishing to participate, it will be required to sign the informed consent document and to fill out the medical history sheet.
• An evaluation phase: in which it will be necessary to fill out a number of questionnaires during two consecutive menstrual periods.
• An intervention phase: consisting of 12 30-minute treatment sessions, once a week. The patients will be randomly assigned to one of the two groups. In both groups, a current will be applied to different locations on the legs. The technique will be performed through four/two electrodes leg attached to the skin. This stimulation will not be painful at any time nor will it have harmful effects on the patients health. In this phase, the individual should continue filling out the questionnaires provided in each period. On the last day of treatment, a scale of satisfaction with the treatment will be retrieved.
• A re-evaluation phase: in which the individual shall fill out a number of questionnaires a month, 3 and 6 months after finishing the treatment.

Inclusion Criteria:

• Women aged between 18 and 43.
• Women with regular menstrual cycles (range between 21 and 35 days).
• Women with a visual analogue scale (VAS) between 4 and 10 (moderate to severe pain) during at least 50% of annual menstrual cycles and / or during the last 3 cycles in the suprapubic area, abdomen, lower lumbar area , perineum and / or medial side of the thighs during the first and / or second day of your menstrual cycle.
• Sign the informed consent document to participate in the study.

Exclusion Criteria:

• Women on hormonal therapy or who have an Intrauterine Device implanted.
• Women diagnosed of secondary dysmenorrhea by their gynecologist (endometriosis, ovarian cyst, etc.) in the last 18 months.
• Women who have underwent a surgery during the study.
• Women who have underwent abdominal and pelvic surgery or who have given birth (vaginal or cesarean section) in the last 6 months.
• Women with lesions on the skin of the upper-internal face of the ankles (scars, erosions or cysts).
• Women who are pregnant or planning a pregnancy.
• Women with pacemakers, uncorrected coagulopathies, severe comorbid disorder, cancer (in the last 5 years or now), severe mental disorders or neuropathies that affect the nerves of the pelvis or lower extremities.
• Physiotherapy or electrotherapy treatments that are related to the pathology or study areas of the month prior to the start of the study.