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Heavy Menstrual Bleeding Evaluations Should Consider Variations in Product Absorption

October 31, 2023

November 2023

Thomas R. Collins

Thomas R. Collins is a medical journalist based in West Palm Beach, Florida.

Some newer menstrual products such as discs and period underwear have very different absorptive capacity for blood than pads or tampons, but these differences might not be considered when patients are assessed for heavy menstrual bleeding (HMB), according to findings published in BMJ Sexual & Reproductive Health.

The study — the first to study the absorption of newer menstrual products using actual blood — should be cause for clinicians to refine their assessments and take more thorough menstrual histories so menstrual bleeding doesn’t go unaddressed, researchers said.

The validated clinical tool used to diagnose HMB is the Pictorial Blood Loss Assessment Chart (PBAC), which is based on the saturation of pads and tampons. These products are typically referenced when physicians discuss menstrual bleeding with patients, even if the PBAC, which requires recording bleeding through a menstrual cycle, is not used, said Bethany Samuelson Bannow, MD, MCR, the study’s lead author and associate professor of medicine in the Division of Hematology/Medical Oncology at Oregon Health & Science University in Portland.

“We were noticing in our clinic that a lot of folks are moving toward using menstrual cups,” she said. “And you always hear about folks using menstrual underwear, even though it’s not so much in our clinic population. And there’s really no metric for diagnosis of HMB that takes those things into account. It’s really, ‘How often do you change your pad or tampon?’”

The study used expired human packed red blood cells — rather than saline, which is often used — to evaluate 21 products across five categories: tampons, pads, discs, cups, and period underwear. Overall, discs absorbed the most — ranging from 40 mL to 80 mL, depending on the brand and size. Tampons absorbed between 20 mL and 34 mL, pads between 31 mL and 52 mL for most types, and cups between 22 mL and 35 mL. Underwear absorbed the least, ranging between 1 mL and 3 mL.

Because the frequency of product changing is often included in an HMB assessment — in addition to the duration of a menstrual period, clotting, and other factors — the differences in absorbency could affect whether HMB is detected, Dr. Samuelson Bannow said.

“The current metric of defining HMB only when a pad or tampon is saturated every one to two hours greatly underestimates blood loss and rates of HMB,” researchers wrote. “This knowledge is critical to identify accurately when blood loss has reached a critical level with newer menstrual products and requires the patient to seek care.”

Physicians have “very little awareness” about the difference in the absorbency of these products, Dr. Samuelson Bannow said. In general, they should also be speaking to their patients more often about their menstrual history and in more detail.

“The way we take our histories in clinic also needs to be modified, with more attention to what types of products are being used and the absorbency,” she said. “That is key.

“It’s been an effort for the last several years just to get folks to start asking about product changing,” she added. “I think the standard for most clinicians is to not actually take a menstrual history.”

This discussion might not need to take place with all patients, she said, but certainly with patients with iron deficiency or those being seen for a bleeding disorder evaluation.

“As a hematologist, I did not get training on how to take a menstrual history — that’s been something that I’ve learned from gynecologists — so I think we have some learning and growth to do,” she said. “There’s been a lot of harm to patients by the stigma and taboo around periods … it’s led to a lot of unnecessary suffering and missed diagnoses of HMB. Even if all we do is get people talking and thinking about periods, I’ll consider that progress.”

Any conflicts of interest declared by the authors can be found in the original article.


DeLoughery E, Colwill AC, Edelman A, et al. Red blood cell capacity of modern menstrual products: considerations for assessing heavy menstrual bleeding. [published online ahead of print, 2023 Aug 7]. BMJ Sex Reprod Health. doi: 10.1136/bmjsrh-2023-201895.


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