Going against the flow

Concerns are growing over the hazards to women's health posed by inaccurate period product absorbencies. Experts call for more accurate measurement

November 22, 2023
A variety of menstrual products tested with blood
A recent study tested 21 different period products and found that some hold less than 3% of their claimed absorbency. [Credit: Karolina Grabowska | Pexels]

A recent study revealed inaccurate absorbency claims made by manufacturers of tampons, pads and other period products, raising health concerns for hundreds of thousands of women. This could lead to the inaccurate diagnosis of many menstrual disorders. 

Up to one-third of all menstruators are affected by heavy menstrual bleeding, but the current method of diagnosing the condition relies on physicians analyzing the frequency a patient needs to change their period product. If the product’s absorbency claims are off, so are the diagnoses, explains Bethany Samuelson Bannow, a hematologist who studies blood disorders at Oregon Health & Science University. 

In a recent study, Samuelson Bannow and her colleagues measured the absorbance of a wide variety of period products and found false claims about their marketed absorbency. Of the 21 period products tested, the menstrual disc absorbed the most at 80 milliliters, which was 5% more than advertised. Yet, period underwear held only a mere one milliliter of blood, despite advertising claims of holding up to 40 milliliters.

Perhaps the most shocking revelation, experts say, was that prior to this study, none of the products had ever been tested with human blood. Instead, manufacturers tested their absorbency with water or saline solution, which has a very different viscosity than blood. 

“When I read this paper, I was shocked. All this time, everything we’ve known about menstrual absorbencies is just what the companies claim?” says Paul Blumenthal, a gynecologist at Stanford University, who co-authored a follow-up editorial to the absorbency study. “There are standards for so many things in our lives; hot pepper sauces have a scale based on their heat level, but we don’t even have standards for menstrual products.” 

“Our work highlights the gap between the goal of menstrual companies in designing products and the goal of physicians in using them for diagnostic purposes,” Samuelson Bannow says. The most recent research into period products took place in the 1980s, she says, when toxic shock syndrome from tampons was first highlighted as an issue. “In this way, product design is reactionary, not precautionary.”

Some menstruators may have no idea how much they are bleeding in a cycle, says Michela Bedard, executive director of PERIOD, a global nonprofit aimed at improving access to menstrual care. “It’s normal to go through a few products a day, but it’s all relative — which type of product and what absorbency? It’s very difficult to define what a few products a day is, especially if your physician is not a menstruating person.”

If heavy menstrual bleeding is misdiagnosed, the risks are severe: The condition can be a sign of fibroids, pregnancy complications or cancer. 

The existing guidance for assessing menstrual flow comes up short, experts say. The Pictorial Blood Loss Assessment Chart, used by physicians to analyze how frequently a patient changes their period product, relies on product absorbency estimates that may be wrong, Blumenthal says. Plus, it doesn’t consider alternative products such as the menstrual disc, which absorbs the most blood of any product, as shown in the Oregon study. “The chart is no substitute for adequate product standards,” Blumenthal says.

The decades-long failure to test menstrual products with blood is a consequence of the ingrained stigma surrounding that time of the month, says Chella Quint, a period positivity activist and author of two books about menstruation. “There’s this whole idea of being unhygienic, having to be sanitized.”

Quint points out that manufacturers reinforce this stigma when they design inconspicuous products with understated packaging and use blue, rather than red, liquid in their advertisements. Quint contends that the attitude of “we don’t talk about menstruation” leads to “we don’t fund that research.” 

Despite the online firestorm ignited by the Oregon study’s findings, most period product manufacturers have stayed quiet on the issue. An exception is the brand Aisle, which manufactures reusable period products. It released a TikTok explaining how they use a liquid that mimics the texture and viscosity of blood to test their products.

So, how can we design better period products and establish accurate standards? Additional research in the area and manufacturer accountability will help, experts say, as will the development of innovative period products. 

The innovation and redesign of standard period products is a start, Blumenthal says, acknowledging the new spiral-shaped tampon designed by the company Sequel that was recently approved by the U.S. Food and Drug Administration. Meanwhile, the start-up Qvin is treating menstrual blood as a resource for health diagnosis, instead of a waste product. The company is working on menstrual pads with a removable dry blood spot strip that clinicians can then test for diabetes and cervical cancer.

The most urgent task, according to PERIOD’s Bedard, is to improve access to period products and care. “I want people to remember that it’s a menstrual equity issue,” she says, noting that even in the U.S., 1 in 4 students can’t afford appropriate menstrual products. “We can’t assume that people have a variety of products to choose from, or even any products at all,” she adds. “What I hope would come out of a landmark study like this is a push to make higher quality, reusable products available to every menstruator.”

About the Author

Dawn Attride

Dawn is an avid science storyteller from the South-East of Ireland. With her research background in Microbiology, she enjoys unraveling the latest developments in healthcare and biology, as well as covering environmental issues. Her passion for writing stems from her scientific curiosity and dislike of misinformation!


1 Comment

Hello Dawn, your article is a valuable opening to a new debate on period products. I like all that you say, especially that all information about menstrual products comes from the manufacturers. Even well respected clinics (e.g. Mayo Clinic) give out advice that is provided by menstrual product manufacturers. However, I would like to correct you on research (especially Toxic Shock Syndrome) as this has been ongoing since the 1980s and in particular there were many papers in the 1990s, most of it sponsored by the tampon manufacturers. There was one research paper in particular that was NOT sponsored by tampon manufacturers, by Tierno and Hanna (New York) which concluded that Toxic Shock Syndrome was as a result of a reaction of the bacteria Staphylococcus aureus (present in the vagina quite harmlessly) that came into contact with RAYON in the tampon. Rayon is a highly absorbent material and is present in various amounts in all tampons except ALL COTTON tampons. Hope this is useful and may the debate continue.

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