The concept at the heart of the review, menstrual health and hygiene, is broader than many people assume. It encompasses not only the physical materials a person uses to absorb menstrual blood, but also the water, sanitation and disposal facilities that make hygienic management possible, the privacy and safety to change materials without fear of being seen or harassed, accurate information about the menstrual cycle, supportive social environments free of stigma, and access to healthcare for menstrual discomfort and disorders. Together these elements allow people who menstruate to manage their periods with dignity and choice. The researchers argue that climate hazards strike all of these interlinked domains at once, which is precisely why the problem has been so hard to see and so easy to ignore in mainstream climate policy.

To build the evidence base, the team conducted a mixed-methods systematic review of studies published in English between 1947 and 2025, searching four major databases: Medline, Scopus, Embase and Web of Science. They screened 3,890 records and ultimately included 25 studies that met their criteria, spanning quantitative, qualitative and mixed-methods designs. Because the studies varied enormously in the hazards they examined, the outcomes they measured and the methods they used, the researchers synthesised their findings narratively rather than pooling them statistically. The included studies covered floods, which featured in seven papers, air pollution in six, cyclones in three, droughts in three, saltwater intrusion in three, and multiple overlapping hazards in four. That distribution alone tells a story: some hazards have attracted research attention while others, notably extreme heat, remain almost entirely unstudied.

The findings on floods and cyclones are among the starkest. These sudden-onset disasters, the review found, disrupt access to menstrual materials just when supply chains and household budgets are under the greatest strain. Water and sanitation infrastructure is frequently damaged or destroyed, leaving people to manage menstruation without clean water, functioning toilets or safe disposal options. Privacy and safety collapse in crowded evacuation shelters and temporary settlements, where women and girls may have nowhere to change or wash. Access to care for menstrual disorders is limited as health systems are overwhelmed or inaccessible, and the social environment often turns unsupportive, characterised by stigma and restricted mobility that compound the physical hardship.

Slower-onset hazards leave a different but equally damaging fingerprint. Droughts and saltwater intrusion, which increasingly affect coastal communities as rising seas push saline water into freshwater aquifers, constrain hygiene practices primarily through reduced water availability and degraded water quality. When every litre must be rationed among drinking, cooking and cleaning, washing menstrual materials or one’s body becomes a luxury. The review documents how this scarcity affects comfort and dignity, and raises the risk of infection, turning a basic hygiene routine into a daily negotiation with an increasingly hostile environment. These findings matter because slow-onset hazards are projected to expand dramatically in the coming decades, yet they receive far less humanitarian attention than dramatic storms and floods.

The physical health consequences documented across hazards are not trivial. Studies reported dermatological irritation linked to prolonged use of materials or poor hygiene conditions, alongside reproductive and urinary tract infections that flourish when washing and changing become difficult. These are conditions that are largely preventable with adequate water, sanitation and supplies, which makes their persistence in climate-affected settings a marker of policy failure rather than inevitability. The review’s authors emphasise that these outcomes sit within a wider web of disadvantage, since the same communities facing climate stress often already lack robust health services and sanitation infrastructure.

Perhaps the most striking findings concern air pollution, an exposure that operates through an entirely different biological pathway. The studies included in the review linked air pollution exposure with earlier menarche, the onset of first menstruation, and with menstrual cycle irregularities. Earlier puberty has well-documented downstream implications for health across the life course, and cycle irregularities can signal endocrine disruption with effects on fertility, bone health and cardiovascular risk. That environmental pollution could be shifting the timing and regularity of the menstrual cycle itself adds a physiological dimension to a conversation that has mostly focused on access and logistics, and it suggests that the health burden of air pollution on people who menstruate has been systematically undercounted.

The psychosocial toll runs through nearly every study. Shame, anxiety and harassment emerge as recurring themes, whether the setting is a flooded village where pads have run out, a drought-stricken region where washing is impossible, or a polluted city where cycles have become unpredictable. Menstruation is already surrounded by stigma in many societies, and climate shocks appear to amplify that stigma by stripping away the privacy and resources that allow people to manage their periods discreetly. Restricted mobility during disasters can prevent girls from attending school and women from working during their periods, with cascading effects on education and income. The review makes clear that these consequences are not peripheral; they are central to how climate change deepens gender inequality.

Yet the evidence base itself is fragmented, and the authors are candid about its limits. Twenty-five studies across nearly eight decades of publication is a thin foundation for a problem affecting an estimated hundreds of millions of people who menstruate in climate-vulnerable regions. Evidence on extreme heat, arguably the most intensifying hazard of all, is essentially absent, and several domains of menstrual health, including access to accurate information, have barely been studied in any climate context. The geographic spread is uneven, the methods are heterogeneous, and few studies follow people over time. This fragmentation means that the true scale of the problem is likely underestimated, and that policymakers attempting to plan interventions have little rigorous evidence to guide them.

The review’s central message is a call to integration. Menstrual health, the authors argue, must be built into climate adaptation plans, disaster preparedness protocols and humanitarian response frameworks, rather than treated as an afterthought once the emergency phase has passed. That means stockpiling menstrual supplies alongside food and water, designing shelters with private washing and changing facilities, protecting water and sanitation infrastructure from flood and salinity damage, and ensuring that health services for menstrual disorders remain accessible during crises. It also means closing the research gaps the review identifies, particularly around extreme heat, slow-onset hazards and equity, so that the people most exposed to climate change, and most constrained in managing a basic biological process, are no longer invisible in the data that drives policy. As climate hazards intensify, the review suggests, the question is no longer whether climate change affects menstrual health, but how quickly governments and aid agencies will act on what the evidence already shows.

Subject of Research: The effects of climate-related hazards on menstrual health and hygiene worldwide

Article Title: Effects of climate change on menstrual health and hygiene: A global mixed-methods systematic review

Article References: Effects of climate change on menstrual health and hygiene: A global mixed-methods systematic review. (n.d.). https://doi.org/10.1371/journal.pclm.0001083

Image Credits: AI Generated

DOI: 10.1371/journal.pclm.0001083

Keywords: menstrual health, climate change, floods, drought, cyclones, air pollution, saltwater intrusion, water and sanitation, systematic review, public health, gender inequality, humanitarian response