Vol.2, No.4, 311-314 (2010) Health
Copyright © 2010 SciRes. Openly accessible at http://www.scirp.org/journal/HEALTH/
Prevalence of dysmenorrhea in female students in a
Chinese university: a prospective study
Hong-Gui Zhou1, Zheng-Wei Yang2, Students Group3
1Department of Gynecology and Obstetrics, the Affiliated Hospital of North Sichuan Medical College, Nanchong, China
2Morphometric Research Laboratory, North Sichuan Medical College, Nanchong, China; zwyang@nsmc.edu.cn
3Undergraduate students of North Sichuan Medical College, including Hong-Yu Chen, Hua-Qiu Chen, Li Chen, Ling Chen, Yu-Zi
Chen, Xia Chuan, Chun-Ni Deng, Li-Tao Fan, Na Fu, Cui-Mei Gan, Yan Gou, Jing Guo, Li-Ya He, Ya-Jie Hou, Qin Hu, Xiao-Juan
Huang, Lin-Ling Li, Xiao-Zuo Li, Xiao-Lan Lin, Chun-Xia Liu, Dan Liu, Xu Liu, Yin-Hua Peng, Jun Qian, Xue-Fang Ren, Wen
Tang, Hai-Bo Wang, Hui-Min Wang, Qi Wang, Qian-Qian Wang, Yao Xie, Yao-Yao Yu, Ling Zeng, Huan Zhang, Qiong-Yue Zhang,
Jian-Ping Zhao, Chang-Feng Zhou, Xue-Yu Zhou, Yang-Lin Zhou (in surnames’ alphabetical order).
Received 28 December 2009; revised 20 January 2010; accepted 25 January 2010.
This study aimed to investigate the prevalence
of dysmenorrhea in a prospective approach.
Menstruation-related diary data were obtained
from 2640 female college students in North Si-
chuan Medical College; dysmenorrhea and re-
lated factors were analyzed. Dysmenorrhea
occurred in 56.4% of students; 6.5% of dys-
menorrheal students suffered from “hard to
bear” (unbearable) menstrual pain, and 6.5%
had pre-menstrual dysmenorrhea. The more
severe dysmenorrhea was, the longer dys-
menorrhea lasted, and th e longer the duration o f
menstruation and the larger the amount of
menstrual blood flow appeared to be. Dys-
menorrhea occurred on 37% of the menstrual
dates on average and was unrelated to irregu-
larity of menstrual cycles. The percentages of
students taking medicine with mild, moderate
and unbearable dysmenorrhea were 4.0%,
13.3% and 23.7%, respectiv ely.
Keywords: College Students; Dysme norrhea; Pro-
spective Study
Many investigations have been undertaken to determine
the prevalence of dysmenorrhea (painful menstruation),
the commonest (not necessarily the most serious) com-
plaint associated with menstruation [1]. The prevalence
varied widely between investigations. As published in
English, for example, the prevalence (rate of occurrence)
of dysmenorrhea ranged from 72.3% to 89.5% in Nige-
rian and Turkey university students [2,3], and from
59.7% to 85.0% in adolescent girls or young women
[4-8]. In China, university/college students were the
main subjects investigated and the prevalence of dys-
menorrhea (reported in Chinese journals) varied from
31.5%-41.9% [9-13] to 57.1%-79.4% [14-18]. Previous
investigations were, however, retrospective ones by
means of questionnaires. In some investigations it was
stated that the dysmenorrheal data were about the men-
strual pain that occurred every month or frequently [11]
or during the past 3 months [8], and in most other inves-
tigations it was unk nown whether the dysmen orrhea was
defined as the menstrual pain that occurred during the
past 1 or several weeks, or during the last 1 or several
periods. This would cloud the prevalence data. This cur-
rent investigation was therefore undertaken, by adopting
a prospective approach (by means of diary), to stud y the
prevalence of dysmenorrhea in female students in a
Chinese university.
The students investigated were Grades 2004-2007 fe-
male undergraduate students residing on the campus of
North Sichuan Medical College. 37 of them and 2 male
undergraduates constituting the Students Group were
recruited as volunteers to assist in the investigation.
A diary table was distributed to students on October
21, 2007. They were requested to keep record of their
menstrual dates, amount of menstrual blood flow (too
little, moderate or too much), dysmenorrhea (lower ab-
dominal pain associated with menstruation) and medica-
tions taken for menstrual disorder. The completed diary
tables were collected b y January 1 8, 20 08 ( the end of th e
2876 students participated in the study. 230 of them
wrote on the diary that they forgot to fill in part of the
menstrual data and 6 students had no menstruation dur-
H. G. Zhou et al. / Health 2 (2010) 311-314
Copyright © 2010 SciRes. Openly accessible at http://www.scirp.org/journal/HEALTH/
ing investigation. These students being excluded, the
analysis in this study was based on data from the other
2640 students. These students were, on October 2007 at
the beginning of investigation, aged 20.3 1.3 (SD) full
years (range, 16-26; median, 20; 5th and 95th percentiles,
18 and 22).
The first menstruation during the period of investiga-
tion was used for the analysis of dysmenorrhea (includ-
ing pre-menstrual dysmenorrhea), which was divided
into 3 levels: mild (not affecting life or work, without
worry or concern), moderate and unbearable (the origi-
nal Chinese words means “hard to bear” literally). When
a student had 1 or more days of unbearable pain, she was
classified into the group of unbearable dysmenorrhea.
When she had no unbearable pain but had 1 or more
days of moderate pain, she was grouped into moderate
dysmenorrhea. Mild dysmenorrheal students had mild
but no unbearable or moderate pain.
The prevalence of dysmenorrhea was 56.4%. 64.7% of
the dysmenorrheal students had mild dysmenorrhea,
28.8% moderate dysmenorrhea and 6.5% unbearable
dysmenorrhea (Table 1). 3.67% of the 2640 students had
pre-menstrual dysmenorrhea and 1.10% had only
pre-menstrual pain without pain during menstruation . An
average of 8.0% of dysmenorrheal students took medi-
cine; the percentages of students taking medicine with
mild, moderate and unbearable dysmenorrhea were 4.0%,
13.3% and 23.7%, respectively.
The average duration of menstruation was 3.79 1.22
days (median, 4 days); 261 (9.89%) students had abnor-
mal menstrual cycles [19 ] > 40 days or < 18 days. Com-
pared to non-dysmenorrheal students, dysmenorrheal
students were slightly older in age, had slightly longer
menstruation, and had more days on which they felt
there was more menstrual blood loss (Table 1). The
number of dates with dysmenorrhea during menstruation
increased significantly with the increase of dysmenor-
rheal levels (Table 1). In dysmenorrheal students, the
mean number of menstrual dates in the menstrual p eriod
was 4.84 1.24 and dysmenorrhea occurred on 37.1%
22.8% of the menstrual dates. [Note, for each period of
menstruation, the number of menstrual dates is 1 larger
than the duration (days) of menstruation.] There was no
significant difference in the percentage of students with
abnormal menstrual cycles between groups of students
without and with dysmenorrhea (Table 1).
This is a large prospective investigation undertaken to
study the prevalence of dysmenorrhea. It demonstrated
that the prevalence of dysmenorrhea in female college
students in a Chinese university was 56.4%. It also
demonstrated for the first time that 1) dysmenorrhea
occurred on < 40% of the menstrual dates on average,
and 2) the more severe dysmenorrhea was, the longer
dysmenorrhea lasted: the mean number of dysmenor-
rheal dates during menstruation in unbearable dys-
menorrheal students was > 60% larger than that in mild
dysmenorrheal students (Table 1). It was previously
reported that the severity of dysmenorrhea increased
with increasing duration of menstruation or amount of
menstrua l flow [5-6 ]. As also shown in the cu rren t study,
the prevalence or severity of dysmenorrhea was unre-
lated to irregularity of menstrual cycles (Table 1).
The prevalence of dysmenorrhea in college students, a
relatively convenient sample to study, was reported with
wide variation in pr evious studies (see the Introduc tion).
A recent (data collected in June 2006) large (n=15392)
study in 7 universities for minority nationalities reported,
for example, an overall prevalence of 65.6% among the
second and third year college students on campus, with
no significant differences between major nationalities;
however, the prevalence was 84.8% in 1 university (n =
2097) [18]. Strictly speaking, our result of 56.4% ob-
tained prospectively was not comparable to previous
(retrospective) results. A dysmenorrheal woman was
defined in this study as suffering from dysmenorrhea in
one (the first) menstrual period during investigation. So
the dysmenorrheal prevalence obtained in this study re-
flected the prevalence among the women at certain time
point. If a woman was defined as dysmenorrheal even if
dysmenorrhea occurred in only one of her past 10 or 20
periods, each woman would likely be dysmenorrheal, i.e.
the prevalence would be approximating to 100%. The
prevalence (85%) of dysmenorrhea occurring during the
past 3 months among high school students [8], for ex-
ample, would certainly overestimate the prevalence at
certain time point. Previous studies were usually retro-
spective, associated with recall bias, and in most previ-
ous studies it was unknown how the dysmenorrhea was
defined (see the Introduction).
Severity of dysmenorrhea is a subjective feeling,
which may be variable between groups of women. Se-
vere (in comparison with mild or moderate) dysmenor-
rhea was reported in 10%-42% of Western dysmenor-
rheal women [4-6,8] while the percentage was 6.5%-
6.7% in Chinese dysmenorrheal college students [9,15].
Menstruation may be likened to an internal bleeding,
wound or trauma and would naturally cause some con-
cern, painful or uncomfortable feeling, to which women
would get accustomed one way or another. It is therefore
those who feel “hard to bear” (unbearable) that we
should pay special attention to. As estimated in the pre-
sent study, this subgroup of people with unbearable
H. G. Zhou et al. / Health 2 (2010) 311-314
Copyright © 2010 SciRes. Openly accessible at http://www.scirp.org/journal/HEALTH/
Table 1. Main results (mean SD) for college students without dysmenorrhea and with mild, moderate or unbearable dysmenorrhea.
(n = 1150) Mild
(n = 964) Moderate
(n = 429) Unbearable
(n = 97)
Age (full years) * 20.2 1.3abc 20.4 1.4 20.5 1.3 20.7 1.3
Duration of menstruation (days) * 3.72 1.20 3.81 1.20 3.91 1.30 3.90 1.33
No. of dates with dysmenorrhea during men-
struation * - 1.49 0.91bc 2.07 1.06c 2.43 1.31
No. of dates with little blood flow during men-
struation * 1.50 1.49 1.54 1.41 1.70 1.48 1.69 1.52
No. of dates with moderate blood flow during
menstruation * 2.99 1.71 2.97 1.54 2.81 1.60 2.64 1.77
No. of dates with much blood flow during
menstruation * 0.23 0.61abc 0.29 0.60bc 0.40 0.67 0.57 0.93
Percentage of students with abnormal men-
strual cycle # 10.17% 9.02% 11.19% 9.28%
*Data were significantly different (P 0.05) between the 4 groups or the 3 dysmenorrheal groups (Kruskal-Wallis one way analysis of variance on
ranks); significantly different (P 0.05) from the group of mild a, moderate b or unbearable c dysmenorrhea (Du nn's method for multiple comparison).
#Abnormal menstrual cycle: 17 or 41 days; there was no significant di fference between the percentages (2 test: P > 0.50).
dysmenorrhea accounted for 6.5% of the dysmenor-
rheal students, similar to the “severe” (treatment was
needed and school study could not be continued) re-
sults (6.5%-6.7%) previously reported in Chinese col-
lege students [9,15]. Even with unbearable dysmenor-
rhea, the students just seemed to bear it without taking
medicine—less than 25% of them took medicine. Men-
struation-related health education programs are there-
fore needed on campus to promote the menstrual health
of students.
The percentage of dysmenorrheal students taking
medicine for dysmenorrhea was previously reported to
be 50%-58% among Turkey and British undergraduate
students [3,20], 52%-58% among American and Aus-
tralian high school students [7,8], more than 43.8%
among Chinese undergraduate students [18], and
33%-38% among young Sweden women [5,6]. These
results are much higher than our result (8.0%). This
may be indicative of wide variation in the attitude of
medicine taking or in the tolerance to pain between
groups (people) or regions (places), and/or indicative of
the “cumulative effects” in retrospective studies, like
the overestimation of dysmenorrheal prevalence as de-
scribed above.
Dysmenorrhea in the present study is essentially pri-
mary dysmenorrhea [1] since no students in this investi-
gation reported underlying pelvic pathology during study.
In talking with some dysmenorrheal students during
study, we identified a couple of students whose dys-
menorrhea might be secondary, but this was not con-
firmed because they did not seek further consultation or
This study was supported by grants from the Nanchong Bureau of
Science and Technology (N2007-SF010) and the Sichuan Department
of Education (08ZA110).
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