Prevalence and risk factors of primary dysmenorrhoea among medical students: a cross-sectional survey in Indonesia.

Dysmenorrhoea, or menstrual pain, refers to recurrent lower abdominal pain associated with uterine contractions during menstruation. Based on its aetiology, dysmenorrhoea can be classified as primary dysmenorrhoea, which occurs physiologically because of increased prostaglandins during menstruation and secondary dysmenorrhoea, which occurs pathologically as a result of other gynaecological problems, such as endometriosis or adenomyosis. 1 3 Dysmenorrhoea is the most prevalent gynaecological disorder, with a prevalence estimated to be between 43% and 93% of all women of reproductive age worldwide. Such diverse estimations also occur in Indonesia, where no precise data on prevalence were found. However, a study in Central Java estimated that around half of Indonesian women have dysmenorrhoea. 2 4 While the prevalence of dysmenorrhoea is predicted to be high, it often receives inadequate attention. Societal perceptions of menstrual cramps, coupled with cultural narratives surrounding their management, may significantly impact women’s experiences and health-seeking behaviours. For instance, a study on 435 medical students in a university in Saudi Arabia reported that only 3.2% of women actively seek assistance in managing dysmenorrhoea. 5 Although primary dysmenorrhoea undoubtedly causes numerous quality-of-life impairments, including sleep disturbances, fatigue, absenteeism in physical and social activities and mental health issues, public awareness is relatively low. 3 4 6 The aforementioned problems are also related to the limited amount of research on primary dysmenorrhoea, particularly in developing countries like Indonesia, where comprehensive nationwide data on the prevalence and risk factors of the condition are unavailable. This presents a distinct challenge, as epidemiological data play a crucial role in establishing effective disease management and treatment strategies. In response to this gap, various studies conducted in other countries, such as Iran, 7 Turkey 8 and Ghana, 9 have tried to conduct epidemiological surveys across diverse groups of women in their respective countries. Female medical students emerge as a valuable demographic in epidemiological research on primary dysmenorrhoea. Sharing similarities with the intended population of reproductive age women (<25 years old) where dysmenorrhoea is highly prevalent, 10 11 medical students also possess a higher baseline knowledge and interest in primary dysmenorrhoea, facilitating the survey-taking process. Additionally, engaging in research on medical students may enhance their awareness of primary dysmenorrhoea as future physicians. 5 Numerous studies in other countries have targeted medical students as their population, enabling more direct comparison. This study aims to measure primary dysmenorrhoea prevalence and identify its associated risk factors among medical students in Indonesia.

This study is a component of a larger research project, ‘Primary Dysmenorrhea: Prevalence, Perception, Behavior, and Quality of Life among Medical Students in Indonesia’. The broader project aims to comprehensively examine the impact of primary dysmenorrhoea on medical students, including its prevalence, students’ perceptions and behaviours related to the condition and the overall effect on their quality of life. This specific study focuses on assessing the prevalence and identifying risk factors associated with primary dysmenorrhoea within the medical student population. The data collected on prevalence and risk factors will provide foundational insights that will inform subsequent phases of the project, which will explore how students perceive dysmenorrhoea, their behavioural responses and its impact on their academic and daily lives. The findings of this study are integral to understanding the broader context of primary dysmenorrhoea and developing targeted interventions or educational programmes to support affected students. The project has received ethical approval ensuring that all methods were conducted in accordance with relevant guidelines and regulations. Details about the larger project are available on request. For more information or to request access to the proposal, please contact the corresponding author via email. A cross-sectional survey was conducted among female undergraduate medical students in Indonesia from 17 June to 31 July 2021. All data were collected online via a self-reported questionnaire using Google Forms (docs.google.com/forms). Participants were recruited through a snowball sampling method via social media and student organisations. On distribution, participants were encouraged to forward the survey to other relevant respondents. To control for duplicate entries, we implemented a combination of technical and procedural measures. The questionnaire settings restricted submissions to one per email address. Additionally, participants were instructed to complete the survey only once, and responses were reviewed to identify and remove any duplicate entries based on matching demographic information and response patterns. The study population included all female undergraduate medical students in Indonesia with internet access. The inclusion criteria were: (1) providing consent, (2) experiencing menstrual cycles, (3) identifying as Indonesian female medical students, (4) residing in Indonesia during the survey period and (5) having no self-reported diagnosis of pelvic pathology (eg, endometriosis, fibroids or ovarian cysts). International students were excluded from the study to ensure the focus remained on Indonesian nationals. Prior to completing the questionnaire, respondents were presented with an online informed consent form detailing the purpose and methods of the study. Consent was obtained through a yes–no question confirming their willingness to participate. Respondents were also informed that their data would remain completely anonymous. It is important to note that pelvic pathology was self-reported, which could result in under-reporting as some conditions may not be diagnosed. This limitation has been addressed in the limitations section of the study. The minimum required sample size was calculated with an online sample size calculator (Raosoft, Seattle, Washington, USA). 12 As we were unable to obtain an exact number of female undergraduate medical students in Indonesia, the population size was estimated to be~31 250 students, based on previous research. 13 With a margin of error of 5% and a confidence level of 95%, a minimum sample of 380 participants was required for this study. To account for the potential bias introduced by the non-random nature of the snowball sampling method, we applied a 20% design effect to the calculated sample size, resulting in a minimum required sample of 456 participants. Eventually, we collected data from 630 participants, which was sufficient to support the robustness and reliability of our study. In our study, we used a validated questionnaire in Bahasa Indonesia to assess the prevalence and risk factors of primary dysmenorrhoea among Indonesian women. 14 The questionnaire comprised three main sections: (1) demographic, socioeconomic and behavioural variables, (2) health and menstrual history variables and (3) the perception of pain. The first two sections aimed to gather the independent variables, while the third was about the dependent variable. The independent variables were grouped into several categories. The demographic variables included age (continuous; median, IQR), domicile (categorical; Java vs non-Java) and race (categorical; native Indonesian vs Indonesian of foreign descent, such as Chinese or Arab descent). Socioeconomic variables consisted of academic level (categorical; preclinical vs clinical) and parental income (categorical; four levels based on income brackets) whereas behavioural variables included breakfast frequency 15 (categorical; seldom vs often). Lastly, health-related variables included body mass index (BMI) (continuous; median, IQR), family history of dysmenorrhoea 16 (defined as a positive history of menstrual pain in any biological relative within the first, second or third degree; categorical; with vs without), as well as menstrual characteristics such as age at menarche (continuous; median, IQR), years from menarche (continuous; median, IQR), cycle length (categorical; <21 days (shorter) vs ≥21 days (normal-longer)) and length of menstrual flow (categorical; normal vs menorrhagia). The dependant variables gathered in the third section were the occurrence and severity of primary dysmenorrhoea among medical students. Dysmenorrhoea occurrence was defined as the presence or absence of menstrual pain, while dysmenorrhoea severity was categorised dichotomously into mild and moderate-to-severe pain levels. We used the Verbal Multidimensional Scoring System (VMSS), a widely-used tool for measuring menstrual pain 17 which has been validated in Bahasa Indonesia, 14 to assess participants’ perception of dysmenorrhoea severity. Detailed data categorisation and cut-offs for each variable are given in online supplemental material S1 . Data collection was conducted via Google Forms, and responses were exported to MS Excel for Office 365 (Microsoft Corporation, Redmond, Washington USA) for preliminary cleaning and coding. Afterward, the cleaned data set was transferred to Stata V.18.0 (StataCorp, College Station, Texas, USA) for statistical analysis. Descriptive statistics were first employed to summarise the data. Categorical variables were presented as frequencies and percentages, while continuous variables were described using either means and SD for normally distributed data or medians and IQRs for data that were not normally distributed. Normality was assessed using the Kolmogorov-Smirnov test. Univariate logistic regression analysis was performed to explore the association between each independent variable and the dependent variables, namely dysmenorrhoea occurrence and severity. For the analysis of dysmenorrhoea severity, the outcome was dichotomised into mild versus moderate-to-severe pain. Independent variables were included in the models as either continuous or categorical based on their characteristics and the distribution of the data. For instance, age and BMI were treated as a continuous variable, whereas domicile was analysed as a categorical variable according to prespecified thresholds. Parental income was treated as an ordinal categorical variable, which is a specific type of categorical variable that has a meaningful order among categories. To account for potential confounding factors, multiple binary logistic regression was conducted. Covariates that showed an association with the outcomes at a significance level of p≤0.20 in the univariate regression analysis were included in the multiple binary logistic regression models. This threshold was chosen to ensure that no important variables were omitted from the final models. 18 Two separate multiple binary logistic regression models were constructed. The first model examined the association between independent variables and dysmenorrhoea occurrence (yes/no) using the full sample (N=630). The second model was restricted to participants who reported experiencing dysmenorrhoea, with the outcome being severity (mild vs moderate-to-severe pain), leading to a change in the total sample size for this analysis (N=575). The significance level for statistical hypothesis tests was set at 5%, with p values<0.05 considered statistically significant. Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

A total of 676 respondents completed the survey. Due to incomplete data in some respondents, we only included 630 valid participants with a median age of 20 (IQR: 19–21) for analyses. Most of the respondents were in their preclinical years (85.87%) and of native Indonesian race (88.73%). A large share of the respondents live in Java (57.78%), the most populous island in Indonesia. In terms of socioeconomic status, most participants came from families with a monthly parental income of more than Indonesian rupiah 5 000 000 (76.83%), which put them in at least the upper middle class in Indonesia. 19 In addition, the majority of the respondents (69.37%) reported their BMI to be below 23, the cut-off for overweight status in the Asian population. 20 In contrast, breakfast habit was split equally, between those who reported seldom (53.02%) and often (46.98%). In terms of menstrual characteristics, approximately one-fifths of respondents reported a shorter cycle length of (20.32%) and menorrhagia (19.37%). Although not constituting a majority, the prevalence of a family history of dysmenorrhoea was relatively high at 45.87%. The median age at menarche was 12 (IQR: 11–13) and the median years from menarche was 8 (7–9). Further details on the participants’ characteristics can be seen in table 1 . As continuous variables, data are presented in median (IQR). As categorical variables, data are presented in frequency (percentage). Statistically significant p value analysed through univariate logistic regression. Parental income was treated as an ordinal categorical variable, reflecting an assumed linear relationship across categories and is shown in thousands of Indonesian rupiah. Defined as having a menstrual flow that lasts >7 days. BMIbody mass index Our study revealed that primary dysmenorrhoea is prevalent among 91.27% of medical students in Indonesia. Among those experiencing primary dysmenorrhoea, a slight majority (52.35%) reported moderate-to-severe pain. Univariate regression analysis ( table 1 ) revealed that dysmenorrhoea occurrence was positively associated with a family history of dysmenorrhoea (p<0.001). Additionally, the severity of dysmenorrhoea was positively associated with cycle length and a family history of dysmenorrhoea, whereas it was negatively associated with BMI and being Indonesian of foreign descent. As previously mentioned, covariates that demonstrated an association with either dysmenorrhoea occurrence or severity at a significance level of p≤0.20 in the univariate regression analysis were included in the multiple binary logistic regression models. Multiple binary logistic regression ( table 2 ) was conducted to identify significant risk factors of primary dysmenorrhoea occurrence and severity. After adjusting for confounders, we found that family history of dysmenorrhoea (OR 3.76 (95% CI: 1.89 to 7.45); p<0.001) was the only independent determinant of primary dysmenorrhoea occurrence. Similarly, family history of dysmenorrhoea was also a significant determinant of primary dysmenorrhoea severity, although with a slightly reduced effect size (OR 1.47 (95% CI: 1.04 to 2.06); p=0.027). Additionally, cycle length (OR 1.57 (95% CI: 1.01 to 2.43); p=0.044) yielded higher odds of having moderate-to-severe dysmenorrhoea. In contrast, higher BMI (OR 0.93 (95% CI: 0.89 to 0.98); p=0.003) and being Indonesian of foreign descent (OR 0.50 (95% CI: 0.30 to 0.83); p=0.008) was associated with lower odds of having moderate-to-severe dysmenorrhoea. Analysed through multiple binary logistic regression. Statistically significant p value. Parental income was treated as an ordinal categorical variable, reflecting an assumed linear relationship across categories and is shown in thousands of Indonesian rupiah. Defined as having a menstrual flow that lasts >7 days. BMIbody mass index

This study found a high prevalence (91.27%) of primary dysmenorrhoea among the Indonesian medical students surveyed. This prevalence rate surpasses those reported in similar studies exploring dysmenorrhoea among female medical students in India 21 (73.83%), Hong Kong 22 (77%) and Mexico 23 (20.5%). It is also higher than previous findings among other populations in Indonesia, such as Central Javan 2 (55%) and Jakartan 24 (87.5%) female adolescents. A higher prevalence of dysmenorrhoea among Indonesian medical students could potentially be attributed to their better knowledge of menstruation compared with adolescent schoolgirls. As medical students, they are more familiar with the terminology of dysmenorrhoea, which is often referred to as menstrual pain by non-medical students and may be perceived as a common, non-concerning issue. Enhanced knowledge may lead to greater disease awareness, enabling medical students to recognise that the painful symptom they experience during menstruation are, at some point, not normal. Although there are no specific studies on the effect of disease knowledge on disease awareness in dysmenorrhoea, the relationship between these two factors has been established in previous studies on other conditions, such as diabetes. 25 26 Moreover, stressful conditions experienced during medical training are theorised to contribute to the increased prevalence among medical students, as observed in Pakistan 27 and Lebanon, 28 where prevalence among medical students is significantly higher than among students studying other fields. However, disparities in prevalence observed between different studies could also be explained by other confounding factors, such as different age groups, sociocultural understanding of dysmenorrhoea and varying measurement tools. Therefore, interpretation should be made cautiously. Dysmenorrhoea can be measured using either unidimensional or multidimensional approaches. Previous studies on medical students in Indonesia have commonly used a unidimensional measurement, such as the Numerical Rating Scale. 29 30 Our study, however, employed a multidimensional measurement tool: the VMSS, which considers activity impairment and analgesic consumption in addition to subjective pain perception. The use of a multidimensional scale is generally recommended over a unidimensional scale for pain assessment. 31 Recently developed tools, such as the Working Ability, Location, Intensity, Days of pain, Dysmenorrhoea score 23 and the Dysmenorrhoea Symptoms Interference scale, 32 are also multidimensional and assess multiple dimensions of pain. However, due to considerations of practicality for online surveys, we chose to use the relatively simpler VMSS. This scale has been widely used to measure dysmenorrhoea and has been validated in Bahasa Indonesia. 14 Different measurement tools can yield different prevalence rates of dysmenorrhoea, so it is important to recognise the potential influence of the scoring method when comparing discrepancies between studies on dysmenorrhoea. 23 33 Among students with dysmenorrhoea, a slight majority described having a moderate-to-severe dysmenorrhoea (52.35%). In comparison, higher prevalences were observed among other Asian countries, such as Palestine 34 (80.34%), Lebanon 28 (90.6%), China 35 (65%) and Malaysia 36 (79%). A closer examination of the Malaysian study reveals that the prevalence of moderate-to-severe dysmenorrhoea among Malay, Chinese and Indian participants was 81.7%, 70.7% and 89.5%, respectively. Interestingly, a study involving 384 medical students in Ethiopia reported the same prevalence of moderate-to-severe dysmenorrhoea using the VMSS (52.3%). 37 As mentioned earlier, variations in pain intensity may be influenced by numerous confounding factors, potentially explaining the relatively lower proportion of moderate-to-severe dysmenorrhoea among our respondents. Indonesia is a highly diverse country with multiple ethnicities and races. Even if Indonesians of foreign descent are excluded, native Indonesian populations themselves have variable genetic backgrounds, which may limit the generalisability of findings. Nevertheless, this observation suggests that sociocultural perceptions of pain, potentially influenced by the ancestral origins of each ethnic group, may play a role. Further studies on different races and ethnicities in Indonesia are needed for comparison, although this is challenging given the prevalence of mixed races and ethnicities. 38 In this study, family history emerged as a significant risk factor for both the occurrence and severity of dysmenorrhoea. Comparable results have been observed in similar studies among college students and high school girls. 5 16 28 Genome-wide association analysis has further strengthened the link between dysmenorrhoea and genetic factors, particularly single nucleotide polymorphisms associated with nerve growth factor (NGF). Elevated NGF levels, found in conditions such as endometriosis, colitis and cystitis, may contribute to increased pain sensitivity through mechanisms such as sensitisation of afferent neurons or de novo neuron growth. 39 Studies involving monozygotic twins from mothers with dysmenorrhoea have demonstrated a higher correlation in dysmenorrhoea pain parameters compared with dizygotic twins. 40 The nearly twofold stronger association of family history with the occurrence of dysmenorrhoea compared with its severity may suggest that the severity of dysmenorrhoea is more complex, influenced by additional factors beyond pain threshold and genetic susceptibility. 41 Furthermore, family influence may extend beyond genetics to affect nutritional status, behaviours and knowledge about dysmenorrhoea, thus influencing pain perception. Parents are often the primary source of advice on managing dysmenorrhoea. 36 42 In contrast, several factors were identified as associated with lower odds of experiencing moderate-to-severe dysmenorrhoea. Specifically, BMI showed a negative association with dysmenorrhoea severity, indicating that higher BMI is linked to a lower risk of experiencing moderate-to-severe dysmenorrhoea. This finding aligns with previous research that reported a significant association between lower BMI and higher dysmenorrhoea severity. Some studies suggest that women with a lower BMI may be more likely to experience dysmenorrhoea due to hormonal imbalances and nutrient deficiencies, which can adversely affect menstrual health. The observed inverse relationship between BMI and dysmenorrhoea severity underscores the complex interplay of physiological factors influencing dysmenorrhoeic pain among medical students in our study. 43 44 Another physiological factor influencing dysmenorrhoea severity in our study is cycle length. A shorter cycle length is associated with milder dysmenorrhoea when compared with the combined group of normal and longer cycle lengths, aligning with previous studies that found normal and longer cycle lengths to be associated with higher rates of dysmenorrhoea. 45 50 Longer cycles may involve greater hormonal fluctuations or irregular ovulatory patterns, potentially contributing to more severe dysmenorrhoea. In contrast, shorter cycles may involve less cumulative exposure to these hormones, especially to oestrogen, which could result in lower levels of prostaglandin production and milder uterine contractions. 51 52 Nevertheless, further research is needed to understand the specific mechanisms by which cycle length influences pain severity. Being Indonesian of foreign descent, specifically of Chinese or Arab descent, was associated with lower odds of experiencing moderate-to-severe dysmenorrhoea, suggesting a potential role of race in dysmenorrhoea severity. Despite including a small percentage of individuals of Indonesian foreign descent (11.27%), this finding aligns with previous studies in other Asian countries, such as in the Middle East, China and Malaysia where considerably lower rates of dysmenorrhoea have been reported compared with our study. 36 53 The genetic and molecular mechanisms underlying the effect of family history of dysmenorrhoea are thought to contribute to the observed role of race in dysmenorrhoea severity. 39 40 However, given Indonesia’s highly diverse population, with a mixture of native and foreign descent and significant genetic variability even among native groups, caution must be exercised when generalising these findings. Even if Indonesians of foreign descent are excluded, native Indonesian populations themselves have variable genetic backgrounds, which may limit the generalisability of findings. Not all factors were found to be significant in modifying the occurrence and severity of dysmenorrhoea in our study. While some of these factors have shown significance in previous studies, our contradictory findings may be explained by several factors. For instance, skipping breakfast is known to be strongly associated with dysmenorrhoea, indicating the role of breakfast in maintaining ovarian and uterine function. 15 34 However, we did not find this association in our research. This discrepancy could be attributed to physiological adjustments that occur when skipping breakfast becomes a habitual behaviour. Another notable risk factor that did not yield significant results in our study is academic level, which only showed significance in our univariate regression analysis. High levels of stress, known to increase the risk of dysmenorrhoea, were previously found to be higher in clinical year medical students compared with those in their earlier years. 54 This difference is often attributed to heavier workloads, longer working hours and increased responsibility. 55 However, it is crucial to note that each country has a distinct curriculum for medical school, making direct comparisons of academic burden across countries challenging. Additionally, our study occurred during the COVID-19 pandemic, potentially contributing to increased fear, anxiety and stress in the population. 56 This contextual factor should be considered as a potential confounder in data interpretation. Parental income was another factor that did not show a significant association with dysmenorrhoea severity. While previous research found an association between lower income and primary dysmenorrhoea, 35 our study found a different trend. Though not statistically significant, higher parental income showed a trend towards higher odds of experiencing moderate-to-severe dysmenorrhoea. We hypothesise that individuals from higher-income backgrounds may adopt a more sedentary lifestyle with low physical activity levels, 57 contributing to greater dysmenorrhoea severity. 58 59 Moreover, individuals from higher-income backgrounds may have increased awareness of health conditions, leading to more frequent and severe reporting of symptoms compared with those from lower-income backgrounds. 6 60 61 Further research is needed to confirm these findings and explore the underlying mechanisms. While this study represents valuable data on dysmenorrhoea prevalence among Indonesian medical students, it comes with inherent limitations. The cross-sectional design employed in our research constrains the establishment of causal relationships for identified risk factors. Additionally, despite a sizeable sample size, we did not use a randomised sampling method. Relying on snowball sampling resulted in a concentration of participants in Java, mirroring the current distribution of medical schools in Indonesia (45 out of 89 schools). While this alignment reflects the existing proportion, it introduces potential limitations to the generalisability of our findings. 13 Furthermore, our focus on dysmenorrhoea among medical students, while advantageous due to their higher baseline knowledge and interest in the subject, requires cautious generalisation to the broader Indonesian population. The use of online data collection could also introduce biases, such as the exclusion of students with limited internet access, potentially skewing the results. Unexplored factors not considered in this study may also act as confounders, warranting future investigations to unravel the complex interplay of these variables. Lastly, our use of self-reported questionnaires poses challenges in definitively classifying individuals with primary or secondary dysmenorrhoea, as additional diagnostic tools are needed to discern underlying pathology. Despite these limitations, we hope to bring awareness to this increasingly prominent gynaecological concern. Further health education measures should be conducted to promote menstrual health literacy and ensure an adequate understanding of dysmenorrhoea assessment and management.

There is a high prevalence (91.27%) of primary dysmenorrhoea among Indonesian medical students from diverse backgrounds. Among those affected, more than half (52.35%) reported experiencing moderate-to-severe pain. This elevated prevalence underscores the need for proactive measures to enhance the understanding and management of dysmenorrhoea in Indonesia. Among the risk factors studied, a family history of dysmenorrhoea emerged as the primary and statistically significant predictor for both the occurrence and severity of dysmenorrhoea. Additional significant predictors of dysmenorrhoea severity included BMI, cycle length and race. These findings highlight the multifactorial nature of dysmenorrhoea and the importance of considering various factors in its assessment and management. Given the significance of these results, further research is warranted, particularly in diverse populations, to gather additional data and raise awareness regarding this increasingly prevalent gynaecological concern. The data will be valuable in designing personalised approaches to increase knowledge, modify behaviours and provide medical care and assistance for dysmenorrhoea, taking into account different sociocultural backgrounds.