What can shopping transactional data reveal about relative prevalence of menstrual pain and period poverty in England?

91% of those who menstruate reported to experiencing associated pain. Despite the ubiquity of this phenomenon, the prevalence, extent and sociodemographic variation of menstrual pain remains understudied at national levels. In this paper, we assess the extent and variation of menstrual pain at a national level. We develop a novel proxy measure for menstrual pain, utilising behavioural data extracted from supermarket shopping logs. Baskets where pain and menstrual items co-occur are investigated, and normalized against baskets in which pain or menstrual items occur in isolation. Propensity of menstrual pain purchases are aggregated temporally and geographically across England, prior to linkage with sociodemographic indicators regionally. Findings indicate high prevalence of menstrual pain across England, with 26.7% of customers in our dataset buying pain relief together with menstrual products. People who menstruate are observed to be four times more likely to purchase pain relief with menstrual items than without. Average regional income provides the strongest predictor of menstrual pain co-purchases, with lower income regions exhibiting a 32% lower menstrual-pain purchase than higher income regions. The robust presence of a consistent 28-day cycle in menstrual-pain purchases provides empirical evidence for the use of behavioural proxies for menstrual pain alongside traditional measures. Significant regional differences observed in the prevalence of menstrual-pain transactions across England brings into light existing disparities. Future research into improved understanding of sociodemographic factors associated with menstrual pain could inform strategies to predict and prevent menstrual pain and its adverse impacts.Author summary: Menstrual pain is extremely common, affecting more than nine in ten people who menstruate, yet it is rarely measured at a national level. This study explores how widespread menstrual pain is across England, and how it varies between different regions and groups. Instead of using surveys, the researchers created a new way to estimate menstrual pain by analysing supermarket shopping data. They looked for shopping baskets that contained both menstrual products and pain-relief medicines, comparing them with baskets that contained only one or the other. The results show that menstrual pain is highly prevalent: 26.7% of customers bought pain relief together with menstrual products. People who menstruate were four times more likely to buy pain relief when purchasing menstrual items than at other times. Income levels also played a role. Regions with lower average income showed 32% fewer menstrual-pain related purchases than higher-income regions, suggesting differences in access, need, or purchasing behaviour. The data showed a consistent 28-day cycle in these purchases, supporting the use of behavioural data as a reliable indicator of menstrual pain. Overall, the findings highlight meaningful regional differences and point to the need for further research to better understand and address menstrual pain and its impacts.