Is exercise associated with primarydysmenorrhoea in young women?H Blakey,a C Chisholm,a F Dear,a B Harris,a R Hartwell,a AJ Daley,b K Jollyb

a Medical Students, College of Medical and Dental Sciences b School of Health and Populations Sciences, College of Medical and Dental

Sciences, University of Birmingham, Edgbaston, Birmingham, UK

Correspondence: Dr A Daley, Primary Care Clinical Sciences, Clinical Sciences Building, School of Health and Populations Sciences, College of

Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT UK. Email a.daley@bham.ac.uk

Accepted 1 April 2009. Published Online 14 May 2009.

Anecdotal beliefs that exercise is an effective treatment for

primary dysmenorrhoea have prevailed for many years although

evidence is contradictory. Previous studies have also contained a

number of methodological inadequacies. A questionnaire that

assessed menstrual pain and levels of exercise was administered to

654 university students. Attempts were made to blind the purpose

of the study. A response rate of 91.3% (597/654) was obtained.

Analyses showed no association between participation in exercise

and primary dysmenorrhoea. Prospective studies would be useful

in further research.

Keywords Dysmenorrhoea, exercise primary, menstrual pain.

Please cite this paper as: Blakey H, Chisholm C, Dear F, Harris B, Hartwell R, Daley A, Jolly K. Is exercise associated with primary dysmenorrhoea in young

women? BJOG 2010;117:222224.

Introduction

The epidemiology of primary dysmenorrhoea is difficult to

establish because diverse diagnostic criteria are often used

but estimates range from 25% (all women) up to 90%

(adolescents),1 with 10% of women describing their symp-

toms as debilitating.2 Few women consult their general

practitioner about their symptoms, preferring to self medi-

cate.3 Several factors have been associated with primary

dysmenorrhoea including smoking, depression, heavy men-

strual flow, age, parity and body mass index (BMI). It is

also popularly thought that exercise reduces the frequency

and/or severity of primary dysmenorrhoea. Exercise has

been linked with reduced prevalence of primary dysmenor-

rhoea and associated symptomatology in some studies but

not in others1 and a recent meta-analysis4 of observational

studies for chronic pelvic pain found that exercise was

associated with a small reduced risk of dysmenorrhoea

(OR:0.89, 95% CI 0.800.99).

The methodological quality of previous observational

studies of exercise and primary dysmenorrhoea may be

questioned because they have often included small sample

sizes, potentially leading to underpowered studies. Past

studies have tended to use single item unvalidated questions

to assess exercise which do not take account of different

intensities of exercise that individuals might engage in (i.e.

mild, moderate and vigorous). Many previous studies have

largely ignored confounding factors such as age, parity,

smoking, stress, mood and use of the oral contraceptive pill

(OCP) and failed to rule out the possibility of secondary

dysmenorrhoea as the cause of symptoms. Furthermore,

authors have frequently made no attempt to blind the study

purpose; this is critical because women may over estimate

pain and/or symptoms if they are aware of the research

question(s). Taken collectively, these issues may, at least in

part, explain the inconsistent nature of research in this field

to date and there is a need for studies that address some, or

all, of the methodological issues raised here.

Methods

Women aged 1825 years were recruited from a university

located in the West Midlands. Thirteen heads of schools

within the university were approached for permission to

distribute the study questionnaire to female students at the

end of a lecture; 12 schools agreed to this request. Data

were collected between February and March 2008. A total of

654 questionnaires were distributed. The questionnaire was

entitled Womens Health and Lifestyle Questionnaire so as

to blind the specific purpose of the study. Participants were

asked to indicate their age, ethnicity, height, weight and

current smoking behaviour. Items relating to age at menar-

che, length of menstrual cycle, whether currently menstruat-

ing (menstrual status), use of OCP or intrauterine device,

222 2009 The Authors Journal compilation RCOG 2009 BJOG An International Journal of Obstetrics and Gynaecology

DOI: 10.1111/j.1471-0528.2009.02220.x

www.blackwellpublishing.com/bjogShort communication

parity and history of gynaecological diseases were also

included. Demographic items were piloted for meaning and

presentation.

A modified version of the Godin Leisure-Time Exercise

Questionnaire5 was used (Appendix S1). This questionnaire

asks during a typical 7-day period (a week), how many

times on average do you do the following kinds of exercise

(i.e. strenuous, moderate and mild intensity) for more than

15 minutes during your free time? For the purposes of this

study we amended this statement to 30 minutes or more,

in line with the current government recommendations for

exercise. Thus, participants were asked to report how many

times per week they participate in strenuous (e.g. running,

vigorous swimming, netball and circuits), moderate (e.g.

fast walking, cycling, easy swimming, dancing) and mild

(e.g. archery, bowling, golf, easy walking) intensity exercise

for more than 30 minutes during their free time. Total

weekly leisure exercise score is calculated in arbitrary units

by summing the products of the separate components by 9,

5 and 3 METs, respectively, as shown in the following for-

mula: Weekly leisure exercise score = (9 Strenu-ous) + (5 Moderate) + (3 Light). The amended itemswere piloted for meaning with University students prior to

data collection.

Women rated menstrual pain using a visual analogue

scale (VAS) between 0 (no pain) and 10 cm (extremely

severe pain). Pain was also assessed using a verbal multidi-

mensional pain score (VMPS),6 which grades pain as none,

mild, moderate or severe according to the impact on daily

activity, systemic symptoms and analgesic requirements.

Women who rated their pain as greater than zero were

considered to have primary dysmenorrhoea. Participants

were also asked to specify any analgesic medication and

alternative treatments that they used to treat dysmenor-

rhoea. The mental component score subscale of the SF-12

questionnaire (herein referred to as mood) was included in

the study questionnaire in an attempt to further blind the

purpose of the study.

Data analysis

Data were analysed using SPSS (version 15.0; SPSS Inc.,

Chicago, IL, USA). Multiple regression analyses between

level of pain (as measured by VAS) and leisure time

exercises score was conducted, controlling for BMI,

ethnicity, OCP use, menstrual and smoking status. VMPS

scores were coded as a binary outcome (VMPS scores of

0 or 1 = no/minimal pain, and VMPS 2 or 3 = moder-

ate/severe pain) for use in logistical regression analysis of

leisure time exercise category (high and low categories

according to a median split of scores) and VMPS cate-

gory, controlling for ethnicity, BMI, OCP use, smoking

and menstrual status was performed.

Results

A response rate of 91.3% (597/654) was obtained. The fol-

lowing participants (total n = 27; 4.1%) were excluded (age

>25 years, n = 5; endometriosis, n = 1; pelvic inflammatory

disease, n = 1; fibroids, n = 2; ovarian cysts, n = 18),

resulting in a final sample size of 570 participants. See

Table 1 for participant demographics. Using VMPS, 21.6%

of participants reported no pain and 78.4% experienced

varying levels of pain (mild = 50.5%; moderate = 21.4%;

severe = 5.8%). This corresponds to 72.1% experiencing

no/minimal pain and 27.9% experiencing moderate/severe

pain.

The multiple regression analysis between pain VAS and

leisure time exercise scores, after controlling for mood,

ethnicity, BMI, OCP use, smoking and menstrual status

was non-significant (P = 0.75). Logistic regression between

VMPS category and leisure time exercise category, control-

ling for mood, ethnicity, BMI, OCP use, smoking and

menstrual status was non-significant (P = 0.34).

Table 1. Participant characteristics

n (%)

Age (years)

1819 357 (63.1)

2021 195 (34.5)

2223 9 (1.6)

2425 5 (0.9)

Total 566

Mean (SD) 19.3 (1.1)

BMI (kg/m2)

Discussion

In line with many other studies, but dissimilar to others,

participation in exercise was not associated with dysmenor-

rhoea as measured by VAS score or VMPS, after control-

ling for confounding variables. A number of factors may

account for the discrepancy between studies. A recent

review1 showed that in studies where more than 500 partic-

ipants were included there tended to be no association

between dysmenorrhoea and exercise/physical activity pat-

terns but smaller studies (

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