For as long as I can remember, I recall seeing menstrual products portrayed on TV commercials as pristine white clouds, tested by being soaked with a clean, blue fluid. 

This always seemed kind of silly to me because I grew up in a house where my mom was open about her period. As I got a little older, I expected that I would eventually start my period, too. 

When I think about those commercials now, I believe they all feed back into the culture of “Let’s Sanitize Women’s Experiences,” “Your Body is Shameful and Disgusting,” or “Operation: If You Must Bleed, Let It Be Blue Blood.”

woman selecting period products at the grocery store

Recently, a study was released in BMJ Sexual & Reproductive Health that made people, menstruating or not, do a double-take: All this time, most menstrual products have been tested using a saline solution instead of blood.

The study looked at 21 different kinds of commercially available menstrual products, including tampons, pads, menstrual cups and discs, and period underwear, and tested each in a laboratory to determine the maximum capacity to absorb or fill — using expired human-packed red blood cells.  

At first, I felt more than a bit shocked and even outraged. Really? It was yet another example of women’s health and experiences being undertested and undervalued.

The pictorial blood loss assessment chart (PBAC) measures blood loss in medicine in everything from menstruation to surgery. So why is saline being used to measure absorbency of loss in menstrual products? Why was this being tested in the first place? Why weren’t other aspects of the menstrual experience being examined? Did any of this even matter? 

It turns out, kind of — but there are many more subjective and objective aspects of menstrual health that matter far more than how much fluid a product can hold, including factors like flow rate, level of pain, and more

And, just as importantly, there are many reasons why menstrual health isn’t as well studied as other issues.

But first, what did the period blood study find?

The study set to determine just how much liquid was being held compared to the absorbency labels a product deemed it was designed to hold.

They found that menstrual discs can hold the most blood, averaging 61 milliliters. One brand, Ziggy, can hold about 80 milliliters. 

It should be noted that losing more than this amount during an entire period is considered excessive blood loss, and you should speak with your doctor. To provide a visual example, 60 milliliters is about 2.7 ounces… or one and a half shot glasses.

Tampons, pads, and menstrual cups held slightly smaller amounts: anywhere from 20-50 milliliters. Absorbent pants held just 2 milliliters on average. 

The problem? There was a distinct mismatch between the reported and actual absorbent capacity of many of the studied products, with most products claiming to have a greater capacity than the research found. 

This disconnect between actual measurement and advertised amounts means “we’re probably missing a lot of heavy menstrual bleeding,” says Bethany Samuelson Bannow, M.D., in an article for The Guardian. “While we are unable to directly measure the absorption of menstrual blood, the packed red blood cells we used are at least a closer approximation of the viscosity of menstrual blood than saline."

Well, I would hope so.

Excessive menstrual bleeding can signify more serious conditions like bleeding disorders, certain types of cancer, fibroids, and anemia. Heavy bleeding during menstruation is also “really a mental health and quality of life issue,” explains Candace Tingen, Ph.D., a researcher at the Gynecologic Health and Disease Branch at the National Institute of Child Health and Development, in a piece for Scientific American.

woman using a hot water bottle to relieve her period pain

Why test menstrual products with saline in the first place?

So, why don’t period product manufacturers test absorbency with blood for better accuracy?

It turns out, blood is a precious commodity. According to the National Library of Medicine, over five million people in the U.S. need a blood transfusion every year. Even though there are almost seven million blood donations annually, there are many reasons why hospitals run into shortages and clinicians find themselves hard-pressed to use it for anything other than transfusions. 

Blood is also considered a potential biohazard. Researchers who handle it must undergo training and take special precautions to work with it safely. In contrast, “you don’t have to have any special training to work with saline,” Tingen says. Additionally, blood — and artificial blood — is expensive. A 10-milliliter vial of research-quality human blood costs around $100, while 200 millimeters of high-quality synthetic blood — a lab-made mixture of amino acids and hemoglobin — can run upward of $150.

Labs can buy a liter of saline solution for $45. 

But, even though blood isn’t menstrual blood, studies like this could help doctors better assess whether heavy menstrual bleeding could be a sign of underlying health problems, such as bleeding disorders or fibroids. 

Be the expert in you.

Take the Quiz

Can we stop sanitizing women's periods — and experiences?

Still, we can do better, and we must. 

This study is part of a shift in the greater paradigm toward removing the stigma surrounding women — and their bodies. The more we talk about menstruation, reproduction, bodies, fertility, and other formerly taboo subjects, the more we can break down stigmas and bring light — and research — to them.

Doctors Samuelson Bannow and Tingen say these types of studies do so for menstruation. Discussing menstrual health (and other topics) leads to better care, the development of better products, and improved gender equity in healthcare. “The main thing is just to get people talking about their periods,” Samuelson Bannow adds. 

We also must believe women’s subjective experiences when we hear them. Women are often gaslit by doctors and medical professionals when they describe their symptoms and pain, but menstruation is about more than just blood loss. 

woman doubled over in pain from menstrual cramps

According to Dr. Staci Tanouye, a board-certified OB/GYN based in Jacksonville Beach, for this reason, we need to find methods of measurement that are more holistic and inclusive than the PBAC.

"Blood loss is only one objective factor of menstruation," explains Dr. Tanouye. “Many people try to make this experience objective using the PBAC scoring system, which we use in any situation where there will be blood loss. We weigh pads, gauze, whatever we can correlate with blood loss for the most accurate measure.” However, “It’s not just blood in menstrual blood — there’s cervical mucus and discharge, as well as endometrial tissue.” It’s a complex and subjective experience to quantify. 

“Medical professionals must validate patients' experiences and address their needs instead of placing so much weight into numbers and other objective measures. The art of medicine is listening to and understanding someone’s subjective experiences and helping them to live their life to the fullest by combining it with our clinical and professional experience,” concludes Dr. Tanouye.

And we say, Amen to that. 

Kristin Diversi is a writer and versatile creative. She is passionate about reproductive health and justice and lives in Longmont, Colorado, with her husband and their son.