The main objective of the study is to evaluate the effect of radiofrequency on pain associated with primary dysmenorrhea.

The data collected will be: Intensity of pain with the Numeric Pain Rating Scale (NPRS), pressure pain at three points of referred pain from the gynecological system, need or not to take medication, general quality of life with the SF-12 (short form 12) and quality of life in relation to menstruation with the CVM-22. They will be collected at the start of treatment, after the first post-intervention menstruation and after the second post-intervention menstruation.

This study is a randomized clinical trial with two intervention groups and a control group, whose study population is women with primary dysmenorrhea.

The sample size has been calculated with the G* Power 1.9.7 software using repeated measures ANOVA, assuming a two-sided significance level (α=0.05) and 90% power (β=0.10) and 10% losses. A sample of 45 participants (n) was determined to detect a significant change of 1.5 points in the variable measured with the NRS. Forty-five participants were included in this study. In the two intervention groups, radiofrequency will be applied (20 minute sessions for 3 weeks with a frequency of 3 times/week), transabdominal in one group and intravaginal in the other.

Participants must be women between 18 and 35 years old, with regular menstrual cycles (22-38 days according to FIGO), be nulliparous and also not present any of the exclusion criteria detailed in the study.

The data obtained will be analyzed and compared between the different groups in order to draw conclusions.

Dysmenorrhea is a gynecological clinical entity that can be defined as menstrual pain. It usually begins a couple of days before the bleeding or coinciding with the start of the bleeding and usually lasts between 8 and 72 hours.

The main symptom is pelvic and / or abdominal pain that can spread to the lower back or lower limbs. On a psychological level, it associates pictures of depression, anxiety or irritability. It also affects in a very negative way the quality of life, work and / or academic performance (causing episodes of absenteeism) and the social sphere of the women who suffer from it.

In recent years, alternative treatments to pharmacological treatments have been gaining strength, among which physiotherapy stands out. Techniques such as manual therapy, transcutaneous electrical nerve stimulation (TENS), thermotherapy, kinesiology tape, stretching, therapeutic exercises ... are applied in women with primary dysmenorrhea and have been evaluated in numerous studies, most of which are of poor methodological quality.

In clinical practice, one of the physiotherapy modalities that has been applied the most in urogynecological pathologies in women is radiofrequency. Radiofrequency is a physiotherapy intervention that consists of the transfer of energy to the tissues in a resistive or capacitive way using wave frequencies between 0.5 and 1.5 megahertz (MHz). However, at present, there are no clinical trials randomized and controlled that evaluates the effectiveness of radiofrequency in any urogynecological pathology, including primary dysmenorrhea.

Objective: The aim of this study is to assess the effect of radiofrequency on pain associated with primary dysmenorrhea.

Study Type: Randomized controlled clinical trial with two intervention groups and one control group. In the two intervention groups, radiofrequency will be applied (20-minute sessions for 3 weeks with a frequency of 3 times / week). In one of the two groups the application of radiofrequency will be intracavitary and in the other group it will be transabdominal. The control group will not receive any intervention, with the commitment to treat once the study is finished.

Study subjects: Women between 18 and 35 years old, nulliparous, with menstrual pain attributable to primary dysmenorrhea (self-reported pain in most menstrual cycles and at least in the last three menstrual cycles).

Sample size: The sample size was calculated to identify clinically relevant effects on the primary outcome, numerical pain rating scale.

The sample size has been calculated with the G* Power 1.9.7 software using repeated measures ANOVA, assuming a two-sided significance level (α=0.05) and 90% power (β=0.10) and 10% losses. A sample of 45 participants (n) was determined to detect a significant change of 1.5 points in the variable measured with the NRS. Forty-five participants would be required to detect a significant change, 15 in each group.

Interventions:

Intervention group 1 (G1): A transabdominal application (fixed plate at the sacral level) will be performed.

Intervention group 2 (G2): A vaginal intracavitary application (fixed plate at the sacral level) will be performed.

Control group (C): No intervention will be carried out, with the commitment to carry out a postponed intervention in case of having positive results in the study.

Outcomes:

Primary Outcome Measure:

• Numerical Pain Rating Scale.

Secondary Outcome Measures:

• Questionnaire on quality of life in relation to menstruation (CVM-22), validated in Spanish.
• Pressure Pain Threshold (PPT) in the abdominal region recorded in previous studies.
• Number and quantity of analgesics, anti-inflammatories taken to alleviate the pain.

Key words: Dysmenorrhea, physical therapy modality, diathermy, thermotherapy

Inclusion Criteria:

• Age: 18-35 years.
• Menstrual pain: During bleeding and/or the previous 48 hours.
• Nulliparous.
• Regular menstrual cycles (24-38 days according to FIGO).

Exclusion Criteria:

• Currently using contraceptives that prevent intracavitary application (hormonal intrauterine devices and vaginal rings).
• Have any recent abdominal or pelvic surgery that prevents the application of intra/extracavitary heat.
• Dysmenorrhea secondary to other gynecological pathologies (endometriosis, adenomyosis, uterine fibroids...)
• Pregnancy.
• Have received physiotherapy treatment for the painful episode in the six months prior to the study.
• To present situations of contraindication of diathermy, radiofrequency or tecartherapy: implanted devices that work with batteries (pacemakers), metallic implants near the lumbopelvic region, uncontrolled or recent cancer processes, recent hemorrhages, alterations in sensitivity in the area to be treated , local active infections near the region to be treated, febrile states, skin wounds and epileptic processes.

women with menstrual pain