Underwear and reusable pads show the highest levels of a marker indicating intentionally added PFAS, raising concerns about the safety of menstrual products, according to new research.
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Reusable women’s hygiene products can contain toxic chemicals, according to a study published last week that tested items from North America, South America, and Europe.
Published in Environmental Science and Technology Letters, the peer-reviewed article specifically found evidence of per- and polyfluoroalkyl (PFAS) substances in eco-friendly menstrual and incontinence products, reviving the debate about the safety and health effects of feminine hygiene items.
PFAS, also known as "forever chemicals," consist of a large group of man-made substances with exceptional resistance to degradation. For more than 70 years, they have been added to various consumer products, among others, to enhance resistance to water, grease, and stains.
The research team tested 59 products from five categories: period underwear, reusable pads, reusable incontinence underwear, reusable incontinence pads, and menstrual cups.
To assess PFAS presence, scientists measured the total fluorine content, a chemical element whose elevated levels typically suggest the likely presence of ‘forever chemicals’. They then extracted a smaller subset of 19 products and conducted a more in-depth analysis, targeting the levels of specific PFAS.
PFAS were detected in 100 per cent of the smaller sample of 19 products. Evidence of intentionally added PFAS was found in nearly 30 per cent of the full group of 59 products, with period underwear and reusable pads showing the highest rates.
Marta Venier, one of the study’s authors and an environmental chemist at Indiana University, explained that the distinction between intentional and unintentional PFAS presence depends on the amount of total fluorine detected.
“When levels were above a certain threshold, that indicates that PFAS were added to the product intentionally to impart properties such as waterproofing, for example,” she told Euronews Health.
In contrast, lower levels likely point to unintentional contamination during the manufacturing process, she added.
This distinction is particularly significant. “In each category of products, we found items that did not have intentionally added PFAS. This shows that you can still make these products without adding PFAS,” Venier pointed out.
“This tells us they [PFAS] are not a necessary addition to make the products functional,” she continued.
What are the health risks of PFAS on women’s health?
PFAS include more than 10,000 substances; as a result, research has not fully determined the specific health effects of each one.
Despite this gap, there is strong scientific evidence linking PFAS exposure to adverse health outcomes.
In 2023, the World Health Organization (WHO) classified two PFAS as carcinogenic and possibly carcinogenic to humans. These included perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), both banned in the European Union.
In addition to the risk of tumours, PFAS can damage the immune system of newborns due to maternal exposure to these toxic chemicals, which tend to accumulate in bodies over time, Tina Kold Jensen, a physician and environmental epidemiologist at the University of Southern Denmark, told Euronews Health.
“You are exposed to these substances through hygiene products, then it will take at least four years before half of what you're exposed to is out of the body. And since it's there, women of reproductive age pass them on to their children through the placenta and breast milk,” she said.
Jensen also noted that PFAS exposure has been associated with other health issues, including high cholesterol, altered liver enzymes, kidney cancer, and reproductive problems. However, she emphasised that not all of these effects are fully confirmed and said that further research is needed.
Another uncertainty concerns whether the direct contact of pads with the skin poses greater, lesser, or equal health risks compared to environmental exposure to 'forever chemicals'.
“PFAS exposure is mostly through the gastrointestinal channel. (...) Skin is quite a good barrier, but we don’t know much. But here we’re talking not only about the skin but also the vagina, its lips, that’s different,” Kold Jensen said.
Regarding reusable pads, Jensen added that environmental exposure is another concern: “There’s a lot of PFAS in the environment, and they will definitely get into the environment once you wash the pads,” she said.
To sum up, there are still more questions than answers when it comes to the effects of PFAS on women’s health. But do these eco-friendly pads pose other health risks?
What do we know about reusable menstrual products?
Sustainable period products are becoming increasingly common among young people.
According to a 2022 study, in Spain, the use of reusable hygiene products surpassed that of disposable ones among people aged 26 to 35 at the time of the survey.
The Catalan government launched a public health initiative offering a free menstrual cup, one pair of underwear and two packages of cloth pads to reduce both period poverty and the waste generated by disposable products last March.
Reusable products, in fact, have been shown to be more sustainable alternatives to single-use items. Specifically, menstrual cups appear to have the lowest environmental impact, followed by period underwear and reusable pads.
Aside from recent concerns about PFAS, reusable menstrual products have not been shown to pose any other major health threat, according to a global review on reusable menstrual pads. The only relevant concern appears to be skin irritation associated with long-term use of these products or inadequate cleaning or drying of the items.
A similar study conducted on menstrual cups found that these products are generally safe, except for rare cases of vaginal injuries, toxic shock syndrome, or urinary problems.
As for period underwear, major concerns are related to PFAS and other elements. An investigation conducted by the UK-based organisation Which? in 2023 found high silver levels in some popular period pants brands like Intima, M&S and Thinx.
Thinx, in particular, has also been at the centre of the PFAS debate, when in 2020 Sierra Magazine published an investigation with the University of Notre Dame, finding PFAS in the period underwear of the brand. This led to one class-action case against the company, which was settled at the end of 2022.
PFAS, however, are not exclusively present in reusable products, but they have also been found in disposable ones. In 2022, lab tests commissioned by the US consumer watchdog Mamavation and Environmental Health News revealed that PFAS were present in 48% of 46 tested sanitary pads, underwear liners, and incontinence pads.
Another common factor for both single-use and reusable menstrual products is the need for further research to assess the types of PFAS present, their levels, and their health effects.
