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ISSN: 2327-5162

Hyun-Nam et al., Altern Integr Med 2016, 5:4
DOI: 10.4172/2327-5162.1000226

Review Article

Open Access

Effects of Yoga on Dysmenorrhea: A Systematic Review of Randomized
Controlled Trials
Hyun-Nam Ko1, Sam-Sun Le2 and Sang-Dol Kim3*
1Department of Nursing, Jinju Health College, Jinju, Republic of Korea
2Department of Nursing, Koje College, Koje, Republic of Korea
3Department of Nursing, College of Health Science, Kangwon National University, Samcheok-si, Republic of Korea*Corresponding author: Sang-Dol Kim, Department of Nursing, College of Health Science, Kangwon National University: 346 Hwangjo-gil, Dogye-eup, Samcheok-si,
Gangwon-do 245-907, Republic of Korea, Tel: 82-33-540-3362; Fax: 82-033-540-3217; E-mail: nu11110@kangwon.ac.kr

Received date: October 10, 2016; Accepted date: December 01, 2016; Published date: December 05, 2016
Copyright: © 2016 Hyun-Nam K, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract
Objectives: To assess the evidence for the effectiveness of yoga in the management of menstrual pain and thesymptoms associated with dysmenorrhea.
Methods: A search was conducted using CINAHL, the Cochrane library, Embase, PsycINFO, PubMed, andKoreaMed electronic databases to identify randomized controlled trials (RCTs) reported effects of yogic intervention
on dysmenorrhea published in any language between January 1966 and October 2014. Quality assessment was
conducted using the Cochrane risk of bias tool.
Results: Two potential trials were identified of which two were included in the review. Quality critical appraisal
had low or moderate risk of bias. The available data could only be included as a narrative description. A significant
difference was observed between experimental and control groups in pain intensity and pain duration (p<0.05) andthyroid-stimulating hormone (p<0.002), follicle-stimulating hormone (p<0.02), luteinizing hormone (p<0.001), andprolactin (p<0.02) were decreased significantly in the experimental group, compared with the control group.
Conclusions: There is evidence from two RCTs that yoga interventions may be favorable effective fordysmenorrhea. However the findings should be interpreted with caution due to the number of small RCTs and quality
limitation partly. Therefore further high quality RCTs are required to investigate the hypothesis that yoga alleviates
menstrual pain and the symptoms associated with dysmenorrhea, to confirm and further comprehend the effects ofstandardized yoga programs in dysmenorrhea.

Keywords: Dysmenorrhea; Yoga; Systematic review

endometrium and menstrual fluid, which may induce myometrial
hyperactivity and uterine tissue ischemia and pain” [8,9].

Abbreviations: CONSORT: Consolidated Standards of Reporting
Trials; IUCD: Intra-Uterine Contraceptive Device; OCP: Oral
Contraceptive Pills; RCTs: Randomized Controlled Trials; VAS: Visual
Analogue Scale

In addition, various psychological problems have also been
proposed [8,9]. Secondary dysmenorrhea can occur many years after
menarche and is associated with identifiable pelvic pathology such as
endometriosis [8,9].

Introduction

Dysmenorrhea is characterized by cramping lower abdominal painthat may radiate to the lower back and upper thighs and is commonly
associated with nausea, headache, fatigue, diarrhea, lethargy, breast
tenderness and emotional symptoms [5-7,10].

Although the prevalence of dysmenorrhea varied in range from 25%of menstruating women to 90% of adolescent females or 45% to 95% of
any age, dysmenorrhea seems to be the most common gynecologicalcondition in women, regardless of age, race, or nationality [1-4].
Furthermore, dysmenorrhea is a critical global health issue inreproductive age women, as it causes school absences, poor academic
performance, lost work time, and has a significantly negative affect ondaily activities [5,6]. Dysmenorrhea is generally defined as difficult
monthly flow and describes painful menstruation of uterine origin[2,7].
Dysmenorrhea can be classified into two subtypes. The pathogenesisof primary dysmenorrhea is commonly explained by “an abnormal
increase in vasoactive prostaglandins originating in secretory

Altern Integr Med, an open access journal
ISSN:2327-5162

Dysmenorrhea is usually treated with drugs such as oral
contraceptive pills or non-steroid anti- inflammatory drugs [2,10]. A
variety of alternatives for dysmenorrhea, such as transcutaneouselectrical nerve stimulation, acupuncture, acupressure, topical heat,behavioral interventions, relaxation, and herbal and dietary therapies,
are increasingly growing in attention [2,8,11,12].
A growing body of evidence supports the belief that yoga benefits
physical and mental health via down-regulation of the hypothalamicpituitary-adrenal axis and the sympathetic nervous system [13,14].
Yoga may be a safe and cost-effective intervention for managing
menstrual problems [9]. Yoga plays an important role in reducing

Volume 5 • Issue 4 • 1000226

Citation:

Hyun-Nam K, Sam-Sun L, Sang-Dol K (2016) Effects of Yoga on Dysmenorrhea: A Systematic Review of Randomized Controlled
Trials. Altern Integr Med 5: 226. doi:10.4172/2327-5162.1000226

Page 2 of 5
stress and sympathetic activity, increasing parasympathetic activity,
improving one’s quality of life, and decreasing psychological symptoms
levels [3-19].
As stated, there is evidence for the benefit of yoga in reducing pain
and symptoms of dysmenorrhea. However, the quality of the evidence
deeds to be examined to establish whether or not we can advocate yoga
as an alternative and complementary therapy for women with painful
periods. Therefore, the aim of this review is to assess the evidence forthe effectiveness of yoga in the management of menstrual pain and thesymptoms associated with dysmenorrhea.

Methods
Search strategy
The review was planned and conducted in accordance with
Consolidated Standards of Reporting Trials (CONSORT) guidelines
for Reporting Parallel Group Randomized Trials [20]. We searched
CINAHL, Cochrane Library, Embase, PsycINFO, PubMed, andKoreaMed electronic databases to identify RCTs published throughOctober 2014. Our search terms were as follows: (1) yoga (“yoga” or“yoga nidra”) and (2) dysmenorrhea (“dysmenorrhea” or “menstrual
cramps” or “menstrual pain”).
We manually searched the reference lists by ‘footnote chasing’ toidentify any additional studies relevant to our analysis. Two
independent investigators reviewed all the articles from the previous
search based on the following selection criteria. Statistical practitioners
trained these researchers in systematic review methods and metaanalytic operations. All potentially eligible studies were retrieved andthe full-text articles were reviewed to determine whether they met theinclusion criteria.
To be eligible, studies had to meet the following conditions. The
inclusion criteria was evaluated by two researchers independently
using the criteria recommended by the Cochrane Menstrual Disorders
and Subfertility Group and the Consolidated Standards of Reporting
Trials [7,12,20]:
Population: Women in the trials had to meet all the following
inclusion criteria for the trial to be included in the review:
dysmenorrhea (pain affecting daily activity or with a high baseline
score); dysmenorrhea in the majority (>50%) of menstrual cycles;
dysmenorrhea for at least one day of menses; of reproductive age;primary or secondary dysmenorrhea. If participants in the trial met
any of the exclusion criteria, the trial was not included in the review:
With irregular or infrequent menstrual cycles (usually outside of thetypical range of a 21 to 35 day cycle); using an intra-uterine
contraceptive device (IUCD) or taking oral contraceptive pills (OCP).
Intervention: Randomized controlled trials were included that usedyoga as an intervention to review or reduce symptoms associated withdysmenorrhea compared with no yoga.
Comparison: Any randomized controlled trials (RCTs) comparing
yoga (as treatment) for dysmenorrhea versus no yoga;
Outcomes: Primary outcomes were; (1) pain relief (measured either
by a visual analogue scale (VAS), other scale (menstrual disorders
questionnaire), or dichotomous outcome (i.e. pain relief yes or no), (2)overall improvement in symptoms (measured by changes in

Altern Integr Med, an open access journal
ISSN:2327-5162

dysmenorrhea symptoms, either self-reported or investigator-observed
treatment effectiveness, or other similar measures), (3)pathophysiological parameters improvement (measured by change inhormone levels, serum homocysteine and nitric oxide levels etc.), (4)adverse effects from treatment (incidence and type of side effects).
Secondary outcomes were; (1) restriction of daily life activities(measured as the proportion of women who reported activity), (2)absence from work or school (measured as the proportion of womenreporting absences from work or school, and also as hours or days ofabsence as a more selective measure), (3) requirement for medication
additional to assigned treatment (measured as a proportion ofrequiring analgesics additional to their assigned treatment).

Quality assessment
Two reviewers independently conducted assessments using a criticalappraisal Cochrane risk of bias tool RCTs, which was recommended by
the Cochrane Handbook for systematic Reviews of Interventions [21].
The Cochrane risk of bias tool is a six-item list designed to assesssequence generation, allocation concealment, blinding, incomplete
outcome data, selective outcome reporting, and other potential sourcesof bias. Each item was rated as “yes,” “no,” or “unclear”.
According to the Cochrane Handbook, quality of clinical trials candivided into three levels. If the study design fully met the preceding six
criteria, it is considered A level, which means the low risk of bias. B
level would be assigned when one or more criteria were partly met.
If one or more criteria were not met, the study would be defined as
C level, implying high risk of bias. Studies rated as C level would be
eliminated. Any disagreements were resolved by reviewers’ discussion.

Data synthesis
No meta-analysis was performed as only two studies were identified
due to heterogeneity among the included studies. Data are presented
descriptively as no usable data were available.

Results
Study description
A total of 1,120 titles related to our search terms were screened.
Among these, there were 1,025 potential trials identified fromCHINAL, 5 from the Cochrane Library, 61 from KoreaMed, 6 from
PsycINFO and 23 from the PubMed databases.
After the titles were retrieved a total of 257 studies were excluded
either because they were duplicates or they were newsletters,commentaries or no target concepts which mean no dysmenorrhea.
The remaining 863 abstracts were retrieved. After assessing theabstracts, 858 studies were excluded because there was no yogaintervention. Five potential trials were identified in the search
conducted in October 2014.
Five potentially relevant papers were retrieved for evaluation of full
text. After the five full text assessment, three studies were excluded
because two of them did not meet the selection criteria and one had norandomized trial. Figure 1 depicts the literature retrieval process.
Characteristics of the included studies are presented in Table 1.

Volume 5 • Issue 4 • 1000226

Citation:

Hyun-Nam K, Sam-Sun L, Sang-Dol K (2016) Effects of Yoga on Dysmenorrhea: A Systematic Review of Randomized Controlled
Trials. Altern Integr Med 5: 226. doi:10.4172/2327-5162.1000226

Page 3 of 5
The available data could only be included as a narrative description. A
significant difference was observed between experimental and control
groups in pain intensity and pain duration (p<0.05). Thyroidstimulating hormone (p<0.002), follicle-stimulating hormone(p<0.02), luteinizing hormone (p<0.001), and prolactin (p<0.02) weredecreased significantly in the intervention group, compared with thecontrol group. Neither included trial reported data on overall
improvement in symptoms, adverse effects of treatment, restriction ofdaily activities, or absence from work or school etc.

Critical appraisal of quality
Assessments on each methodological quality item for all included
trials are described in Table 1. Of two trials, one trial was quality levelA, another trial was quality level B.

Discussion

Figure 1: Flowchart of included studies through the literaturesearches.

Participants and settings
One RCTs originated in India and another from Iran. Studies wereconducted at a medical university or university midwifery department.
Participants were recruited from obstetrics and gynecologicaldepartments or by interviews at a university. Sample sizes in the 2studies ranged from 92 to 126 participants and totaled 218
participants. Participants’ mean age ranged from 18.0 years to 28.5
years with a median of 23.2 years. Participants had a primarydysmenorrhea in 1 RCT and menstrual abnormalities such as
pathologicalamenorrhea,
dysmenorrhea,
oligomenorrhea,
polymenorrhea, menorrhagia, metrorrhagia, and hypomenorrhea in 1
RCT.

Design and intervention
Two RCTs were identified in this review. Yoga traditions were
heterogeneous between studies: 1 RCT used three poses and 1 RCT
used yoga nidra. One yoga program included yoga postures such as
cobra, cat and fish while the other program included resolve, rotationof consciousness, awareness of the breath, feeling and sensation,
visualization, and ending the practice with resolve. Program length,
frequency, and duration of one trial was one 20 min session a day for
14 days, another trial was 35 min to 40 min session a day, 5 days per
week for 6 months. Yoga was performed under the guidance andsupervision of yoga experts and faculty members in one trial, while
another trial used a booklet with level to level explanations along withmovements and breathing. One RCT compared yoga to no treatment
and another RCT compared yoga nidra with conventional medication
to conventional medication only.

Outcomes

The purpose of this review was to assess the evidence for theeffectiveness of any yoga interventions for the primary or secondary
dysmenorrhea when compared to no yoga. A meta-analysis combining
results from all the trials were not feasible due to only two identifiedstudies and heterogeneity among them. Data were reported
descriptively as no usable data were available.
Only two RCTs were identified and included in this review.
Interventions included yoga pose and yoga nidra to manage menstrual
pain and symptoms [3,4]. Of the two, one trial reported a significant
decrease in pain intensity and pain duration during the menstrualphase of the trained group. The other trial reported a significant
decrease in hormone levels such as thyroid-stimulating hormone,follicle-stimulating hormone, luteinizing hormone, and prolactin in
the intervention group compared to the control group. This study also
stated that after yoga nidra practice, menstrual symptoms such as
painful cramps, heavy bleeding, and irregular periods were relieved inparticipants. Wonderfully, the symptoms were also reduced in bothgroups. The mechanism behind yoga effectiveness for dysmenorrhea isstill unclear. However, in spite of both groups having received
medication, reductions of the symptoms in the yoga group were higher
than in the control group. Therefore, these results support yoga
practice as a positive manager of menstrual pain and dysmenorrhea
symptoms.
According to the mechanism which an abnormal increase invasoactive prostanoids in the endometrium and menstrual fluid may
induce myometrial hyperactivity and tissue ischemia subsequently[2,4,8,22,23], a yoga intervention improves blood flow at the pelvic
level as well as stimulating the release of B endorphine acting as nonspecific analgesics [4]. In addition, another study reported that yoga
poses improve spinal flexibility and strengthens muscles in the backand yoga nidra means psychic sleep which may induce deep relaxation
and, subsequently decrease oxygen consumption causing pain relief[11,18,22,24].
Besides, these results support research findings demonstrating that
relaxation training is an effective treatment for spasmodic
dysmenorrhea or producing improvements in general measures ofdysmenorrhea [25]. As stated, these reviewers identified the two RCTs
in this review as having evidence for the favorable effectiveness of yoga
on dysmenorrhea management.

Two studies were identified that compared a control group with ayoga intervention group and evaluated the effect on dysmenorrhea.

Altern Integr Med, an open access journal
ISSN:2327-5162

Volume 5 • Issue 4 • 1000226

Citation:

Hyun-Nam K, Sam-Sun L, Sang-Dol K (2016) Effects of Yoga on Dysmenorrhea: A Systematic Review of Randomized Controlled
Trials. Altern Integr Med 5: 226. doi:10.4172/2327-5162.1000226

Page 4 of 5

Study, year, Participants
locationInterventions
Experimental group

Population

Interventions

Sample(N;EG, CG)

size Delivery method

Mean age
range)(age

Outcome measures

Main results

AdverseeventsPathophysiologicalparameters

TSH (p<0.002), None
FSH
(p<0.02),LH(p<0.001),
andProlactin(p<0.02)
significantly
decreased after
yoga
nidra
practicewhencomparedwiththe control group.

Limitations

Control group

DurationInterventionist

Drop out n (%)
Rani et al. [9],India/Uttar
Pradesh

University students Yoga nidra+Conventional onlywithmenstrual medication
Conventional
disorders
35 min to 40 min per day, medication
N=126 (EG: 65, 5 days per week in the
CG: 61)morning

TSH
FSH
LH

28 years (-)

6 months

24 (31.9)

Yoga experts and faculty
members

Prolactin
Progesterone
Estradiol
Testosterone
DHEA-S

Rakhshaee[11],
Iran/Rasht

University students Yoga movement with Did not receive Pain relief
withprimary cobra, Cat, andany intervention
pain intensity
dysmenorrhea
fish poses
Pain duration
N=92 (EG: 50, CG:
120 min per day,42)
14 days for menstrual
20 years (18-22)
cycle
28 (30.4)
Booklet described theyogaAsignificant None
difference
wasobserved
betweenexperimental andcontrol groups inpain intensity andpain
duration(p<0.05).

All
menstrual
disorderswere
included.
The sample size was
not large enough toanalysis hypo andhypermenorrhic
subgroup separately.
The phase of themenstrual cycle was
based
on
the
participant’s reports
not on ultrasoundscans.
The obtained data isbased on female
adolescentparticipants’
responses.

Table 1: Characteristics of included randomized controlled trials.
Study, year

Randomallocation

Allocation
concealment

Blinding

Incomplete
outcomeSelective
reporting

Other bias

Quality level

Rani et al. [9]

Yes

Yes

Yes

Yes

Yes

Yes

A

Rakhshaee [11]Yes

Unclear

No

Yes

Yes

Yes

B

Yes: criteria met; No: criteria not met; Unclear, unclear whether criteria were met

Table 2: Methodological quality summary of all included studies.
In the two trials included in this review, they were tooheterogeneous in the participants’ condition (primary dysmenorrhea
or all menstrual disorders), the type of yoga (three yoga posescomposed of physical exercise and breathing or yoga nidra combining
meditation and relaxation), interventionist (only booklet or yoga
experts), duration of the intervention delivery (14 days for menstrual
cycle or 6 months), outcome measures (pain intensity and pain
duration or hormonal responses) etc. The rate of drop out was alsohigh in the two RCTs. In one trial, 24 (31.9%) women were lost to theanalysis for several reasons such as acute pain, family problems,
transportation problems, scheduling, or being non-responsive, etc. In
another trial, 28 (30.4%) participants did not complete the study
because they had an irregular menstrual cycle and failed to comply.
Overall, the trials in this review had no adverse effects, stated thatyoga poses are a safe and simple treatment for primary dysmenorrhea.

Altern Integr Med, an open access journal
ISSN:2327-5162

The quality rating of the trials included in this review had a low ormoderate risk of bias. One trial was unclear about how treatment
allocation was concealed. One of the two trials was single blind and theother did not mention blinding. The trials in this review had moderateor high methodological quality (Table 2). However, no strong conclusion
can be made due to the number of small trials and othermethodological considerations.
This strength of this systematic review includes the use of strict
methodological criteria. Major strengths of this group of studies
include study, the use of randomization, and the quality ofmeasurement tools. Both studies were RCTs. This may be the firstcomprehensive review of yoga for dysmenorrhea.
Limitations were also identified. Menstrual disorders such as
menorrhea,
dysmenorrhea,
oligomenorrhea,
polymenorrhea,

Volume 5 • Issue 4 • 1000226

Citation:

Hyun-Nam K, Sam-Sun L, Sang-Dol K (2016) Effects of Yoga on Dysmenorrhea: A Systematic Review of Randomized Controlled
Trials. Altern Integr Med 5: 226. doi:10.4172/2327-5162.1000226

Page 5 of 5menorrhagia, metrorrhea, and hypomenorrhea were included in one
trial all together. The sample size was also not large enough to analyze
the hypomenorrhic group and hypermenorrhic subgroups separately.
The methods of the participants’ selection have the following flaws.
The phase of the menstrual cycle was based on the participant’s reports
not on ultrasound scans. The obtained data is also based on female
adolescent participants’ responses. Generalizability of findings fromthese two studies is limited due to the number of small trials andlimited quality partly. However, they provide a strong basis for futurestudies and suggest that yoga could provide a safe, cost-effective
therapy for the growing public health issue of dysmenorrhea. There iscurrently a lack of available evidence to support the use of yoga in the
alleviation of symptoms associated with dysmenorrhea. The broader
health benefits of yoga should be discussed with women experiencing
dysmenorrhea. Future research should consider these limitations.
Furthermore, this review contributes to the development of knowledge
in complementary and alternative medicine about how female
adolescents with dysmenorrhea can manage themselves.
In conclusion, although this review has a limited number of small
trials and homogeneity among them, and limited quality partly,
findings from the two trials suggest that yoga practice can effectively
alleviate menstrual pain and the symptoms associated withdysmenorrhea. However further high-quality RCTs are needed toconfirm and further comprehend the effects of standardized yoga
programs to control menstrual pain and symptoms in dysmenorrhea.

8.
9.
10.

11.
12.
13.

14.
15.
16.
17.

Acknowledgement

18.

This study was supported by 2016 Research Grant from Kangwon
National University (No. 620160142).

19.

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