Think Out Loud

OHSU researchers test menstrual products with blood for the first time

By Gemma DiCarlo (OPB)
Aug. 30, 2023 10:46 p.m. Updated: Sept. 6, 2023 10:51 p.m.

Broadcast: Thursday, Aug. 31

OHSU Hospital, 2019.

OHSU Hospital, 2019.

Courtesy of Oregon Health & Science University


Menstrual products like tampons typically have an absorbency level listed on the side of their packaging. But until recently, that absorbency had never been measured with actual blood. Saline, a simpler and less viscous fluid, has been the default test liquid since absorbency standards were first set in the 1980s. However, researchers at Oregon Health and Science University recently tested the absorbency of products like menstrual cups, discs and period underwear, in addition to tampons and pads, with real blood in an effort to better diagnose heavy menstrual bleeding.

Bethany Samuelson Bannow is an associate professor of medicine at OHSU and a co-author of the study. She joins us to explain why research like this hasn’t been conducted before and what the findings could mean.

Note: This transcript was computer generated and edited by a volunteer.

Dave Miller: From the Gert Boyle Studio at OPB, this is Think Out Loud. I’m Dave Miller. Menstrual products like tampons typically have an absorbency level listed on the side of their packaging. But until recently, that wasn’t determined with actual blood. Saline, which is a simpler and less viscous fluid, has been the default since absorbency standards were first set in the 1980s. Researchers at OHSU set out to change that. They tested tampons and pads and cups and period underwear with real human blood in an effort to better diagnose heavy menstrual bleeding. Bethany Samuelson Bannow is an associate professor of medicine at OHSU and a co-author of this new study and she joins us now. Welcome to the show.

Bethany Samuelson Bannow: Thanks so much for having me.

Miller: Thanks for joining us. Why did you come up with this idea to study the absorbency of tampons and other products using actual blood?

Bannow: Well, it started in our clinics. We see a lot of folks with heavy periods in our clinics and we were starting to notice more and more of them using menstrual cups instead of the pads and tampons that we normally use when we’re assessing heavy menstrual bleeding. So to diagnose it in our clinic, the questions we ask are, how often do you change your pad or tampon? But we didn’t have a metric for when people were using cups. So we said, ok, let’s look into this. Let’s look into cups and period underwear and see how much they absorb, so we can better use those tools in our diagnosis of heavy menstrual bleeding.

We wanted to be consistent with what had been done with other products in the past, and so we did a little bit of a dive into the literature to find out how tampons and pads had originally been assessed. And what we found out was, in general, there’s actually not really any regulation for the absorbency of pads. Tampons are more highly regulated because of toxic shock syndrome. Back in the eighties, something called the tampon task force was formed and that’s where, as you mentioned, the saline standard was created. And so we thought to ourselves, well, that made sense for what they were doing, in terms of just trying to stratify tampons by observancy, but that doesn’t really make sense for what we are doing in our clinic, which is trying to estimate how much blood loss of patient is having during periods. So we decided just to start from scratch and do it all with blood to give us some more accurate data.

Miller: What are the repercussions of that decision from 40 years ago now? I mean, I guess the question is how is menstrual blood different from saline, in terms of its likelihood of being absorbed?

Bannow: Well, it differs, actually both ways. So we found that tampons absorbed more, at least red blood cells, than would have been anticipated on the side of the package. And then we found with menstrual underwear that it seemed to absorb less. So either way it’s gonna be a little bit inaccurate. Of course, menstrual blood itself is also different from red blood cells, to be fully open. We weren’t able to use menstrual blood because you can’t collect it in that quantity. But I don’t know that it necessarily has affected the consumer on a day to day basis because I don’t think people go to the store and look for a pad or tampon, [and] say, “Oh, I think I’m gonna lose 30 ml of blood, I’ll pick that product.” But where it does affect things is when we don’t have the knowledge of how things are changing, the landscape of absorbance is changing on the medical side. And when we’re taking our histories. I worry that maybe we have missed some diagnoses of heavy menstrual bleeding because folks are using these products that absorb so much and we’re underestimating their loss.

Miller: That does get to the question of how diagnosis of heavy menstrual bleeding works right now. I mean, as a clinician, what kinds of questions do you ask? And how good a picture can you get of blood loss on any given day or cycle?

Bannow: So there are, I will say, formal tools that can be used. There’s something called a pictorial blood loss assessment chart, where books document how many pads or tampons they use and how saturated they are and that seems to be accurate. Those have been done with diluted blood in the past. But it’s a form that has to be filled out over the course of the cycle. And of course, when a patient comes to you the first day, they’re not bringing that with them. And so we ask specific questions. So I like to ask how many days of bleeding is somebody having for a cycle? So, anything more than seven is abnormal. Certainly bleeding between periods is abnormal. And of course, I ask how many pads or tampons do you use, or how often do you change them? And historically, we’ve fallen back on the idea of changing more often than every two hours is too frequent. But with some of these products, our cut off is actually 80 ml per cycle. With a disc, they could contain very close to that in, in one change. A tampon that absorbs 30 ml, you can use over 80 in three. And so that I think has been the metric that’s gonna be most affected by this.

Importantly, we also ask about how quality of life is affected. And that is the standard currently, so heavy menstrual bleeding that affects personal, social, emotional, physical quality of life. That’s what matters in terms of deciding what to treat. I’m a hematologist, so I have a very specific interest in trying to assess the blood loss in terms of, is this something that could be a sign of an underlying bleeding disorder? But those are the questions that we focus the most on currently.


Miller: Why in the end, does it matter how much blood we’re talking about, from a clinical perspective? If the really key questions are, does somebody have enough red blood cells? Are they anemic? Is there an iron deficiency? I mean, if there’s a clinical response to it, and everybody’s body is different, how important is it to know just how much blood is being lost?

Bannow: So I don’t know the exact amount is hugely critical, but knowing that less than or more than 80 ml is helpful because folks who have more blood loss than that are gonna be at risk for things you mentioned: iron deficiency and anemia. Those are very common in my clinic. It often impacts quality of life at that level. And it could also, in some senses, be indicative of something else going on. So, for example, fibroids can cause heavy menstrual bleeding. Bleeding disorders are associated with heavy menstrual bleeding, which is certainly not to say that everybody who has heavy menstrual bleeding will have an underlying issue. The opposite is actually true. But it is important for us to know that so we’re not missing something else.

Miller: [You] recently tested the absorbency of menstrual products using human blood, which had not really been done before. Why not? I’m really curious about that fateful decision back in the ‘80s. I mean, why did manufacturers use saline instead of blood?

Bannow: That’s a great question. And I think here it’s really important to acknowledge that, unlike other metrics for diagnosing, like blood pressure or thyroid hormone levels, we’re not in control of the metric we’re using to diagnose. I can’t just send somebody to the lab to find out if they have heavy menstrual bleeding or not. We’re really dependent upon products that are created by manufacturers who have a goal that’s very different from ours: diagnosing heavy menstrual bleeding. Their goal is to make products that make getting through the day with a period more practical, which sometimes means absorbing a lot of blood.

When they created the Tampon Task Force, really, what they needed to do was just to standardize, so every tampon manufacturer called their products the same thing in terms of light or super or things like that. And so using saline made sense for that. It made sense to help consumers know, in general, the level of absorbency they need, and make sure that they’re using the minimum absorbency necessary because that will help reduce the risk of toxic shock. And then we, in medicine, have kind of co-opted this to help us diagnose heavy menstrual bleeding, again, because there’s not an easy lab or medical test that we can offer for it. And so that disconnect is really the source, I think of a lot of challenges in the diagnosis of heavy menstrual bleeding.

Miller: And it seems like that disconnect is part of what you’re hoping to correct now. How do you hope that your new findings will help health care providers who are trying to diagnose heavy menstrual bleeding or other conditions? What might be possible now that hasn’t been possible in the past?

Bannow: Yeah, I think we are going to be more aware of folks with heavy menstrual bleeding and miss fewer diagnoses. So if somebody comes into my clinic now and they say, oh, they only change their tampon four times a day, but it’s a super or an ultra, then that’s very different than if they just changed a regular tampon or pad. And so I think having this knowledge is going to help clinicians take more informed histories and make a more informed diagnosis and hopefully capture more episodes of heavy menstrual bleeding that we wouldn’t have in the past.

Miller: How much hope do you have that research like this could break down the societal stigmas around even simply talking about menstruation that still exist? I feel like there has been a change over the last decade. But, it’s not like people talk about menstruation the way they talk about other absolutely standard regular things that happen to human bodies. There is still a difference that I hear.

Bannow: Yes, you are absolutely right. And there’s even some quote out there about, if you do a search, even in the medical literature, for menstrual bleeding compared to, for example, erectile dysfunction, there’s a huge difference there. The thing that gives me the most hope is how much buzz this study has generated. I don’t think that we thought that this was gonna be a big deal that led to a lot of change. I think we thought, this is an important thing. We need to do it, and we’re gonna write it up and hopefully people will access it. But the amount of conversation that I’ve seen in the media, in social media, in medical circles, it’s really inspiring and it really does give me a lot of hope.

I see lots of patients who come into my clinic and they think their periods are normal, but they’re very abnormal and they don’t know that because they’re not talking about it with friends or their doctors. Yeah, that’s the worst thing of all when people aren’t even comfortable talking to their doctors about it. So I see this as such a positive move towards really reducing that stigma and getting more awareness and more comfort talking about menstruation.

Miller: We asked listeners on Facebook, how heavy menstruation affects them. Rebecca Pelly Marie wrote: “It takes me out of the game for a minimum of one to two days every month. It’s been like this for me for at least 36 years with no end in sight. I’m anemic and I’m getting older and I don’t bounce back from it the way I could when I was younger. It creates havoc and makes me miserable.”

We just have a minute left. But, what are the stakes here?

Bannow: I think the stakes are huge. I mean, this is not the first time I’ve heard somebody missing work or school or something on a regular basis, and quality of life is really what it comes down to. So I think the stakes are very high for half the population.

Miller: Bethany Samuelson Bannow, thanks very much.

Bannow: Thank you.

Miller: Bethany Samuelson Bannow is an associate professor of medicine at OHSU, a member of the team that put out this new report that, for the first time, looked into the absorbency of tampons and other menstruation products using not saline but actual human blood.

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