The effect of transcutaneous electrical nerve stimulation (TENS) on decreasing primary dysmenorrhea pain in adolescents

Background: Dysmenorrhea is medical condition indicated by an increase of the prostaglandin (PG) F2-alpha hormone and cyclooxygenase (COX-2) causing hypertonic as well as vasoconstriction activity to the myometrium


INTRODUCTION
Many factors identified to influence the incidence of dysmenorrhea. In general, the factors associated with provoked dysmenorrhea symptoms are menarche, length of menstrual period, blood volume, smoking habits, and family history. High prevalence of dysmenorrhea cases among adolescent stipulated the problem severity and demand for appropriate care (1) .
Pharmacology management is a common treatment for dysmenorrhea by the prescription of analgesics (80%) (4) . Non-pharmacological managements which align with the physiological principle appropriate for dysmenorrhea treatment.
These includes acupuncture, electrotherapy in a form of TENS, body distraction, relaxation and deep breathing, imagination, music therapy, massage and warm compress. Nonpharmacological treatment proven for its safety and long term benefit for quality of life due to the nature of the therapy(3).

Transcutaneous Electrical Nerve Stimulation
(TENS) categorized as a non-pharmacological analgesia therapy tool for pain management (5) . TENS generate electricity to stimulate nerves system and peripherals motors in delivering sensation through the skin surface. This method effective for treat pain with different severity.
In addition, TENS stimulate hypothalamus for endorphins secretion (6). TENS is a tool that is used to reduce the sensation of pain in various fields including dysmenorrhea pain, However, there have not been many reviews of how effective the use of TENS with other non-pharmacological methods is to reduce dysmenorrhea. In this study, it has been shown that the analysis shows that TENS is more effective in reducing dysmenorrhea pain by 3.5% compared to other types of non-pharmacological therapy, namely massage, and is much more effective and efficient.
In primary dysmenorrhea management, TENS serves as a complementary medicine (7). A number of women who had experienced primary dysmenorrhea reported better outcome after TENS administration (5) . TENS works as a pain reliever and alleviate dysmenorrhea symptom. Among patient within the age between 18-25 years old, TENS reported to be effective for lowering pain level (6) . Based on this background, the purpose of this study was to determine the effect of Transcutaneous Electrical Nerve Stimulation (TENS) on reducing primary dysmenorrhea pain.

MATERIALS AND METHODS
This is a quasi-experimental study with pretest and posttest control group design. The results indicated a significant difference of the participants' dysmenorrhea pain level before and after treatment with p < 0.05.
Pain intensity was improved in particular for the intervention group. Before the treatment, participants' pain level in average was 6 (1.70) and ranging from 4-10. The treatment decreased pain intensity to 3.42 (1.6) between the range 1-6.
In addition, reported pain intensity of the control group prior the massage was 4 (1.16) from level 3-6. After the intervention, the pain intensity improved to 1.50 (0.52) between the range of 1-2. The treatments for both groups effective to lower dysmenorrhea pain intensity.

DISCUSSION
Menstruation is a part of the reproductive organs' maturation process. However, various symptoms that occurs emerge to be a disorder (8). First menstruation episode commonly referred as menarche is a physiological process characterized by an increase in the FSH and LH hormones which serve the function to stimulate ovarian target cells. The study results as presented on Table   1 indicated that the participants' menarche was less than 12 years old. Menarche that occurs at the age below 12 affect individual physical and psychological readiness. Physical unpreparedness could cause problem for adolescent, especially pain during the menstrual period due to lack of reproductive organ maturity (11) . Menstrual pain experienced because of excessive contraction in uterus which associated with endocrine factors of the body. Endometrium contraction amid secretion phase will produce prostaglandin F2 to stimulate smooth muscles movement. Another outcome of the excessive prostaglandin F2production including diarrhea, nausea and vomiting in conjunction with the hormone released in the blood circulation (12) .
Results indicated that that average respondent experienced menarche at the age   (17) . Genetic factor greatly affect physical as well as hormonal homeostasis including estrogen, progesterone, testosterone and other steroid hormones that associated with neurotransmitter function (18) (19) . Exercise activity significant to balance the physical and psychological aspect. This study discovered that participants were engaged in physical activity. The activity enhances body metabolic system, in particular promoting blood and oxygen circulation towards the uterus. Lack of physical activity affect blood and oxygen circulation blood in the uterine organs which result in the endorphins production. Endorphins beneficial to maintain psychological health by alleviating stress in reducing dysmenorrhea (21) . Mild physical activity with relaxation potential to ease muscular tension and increase endorphins secretion (12) .
Dysmenorrhea pain is a menstrual disorder that affect overall adolescent health and reduce productivity. Primary dysmenorrhea emerge due to uterine muscle (myometrium) contraction and prostaglandins release (22) . Occurring lesion led to necrotic that activates K + and intracellular proteins. High level of extracellular K +. trigger nociceptor depolarization causing inflammation due to protein exfoliation that infiltrates microorganisms. The process excrete leukotrienes, prostaglandin E2, and histamine (hyperalgesia) or allodynia) (23) .