Toxic Shock Syndrome and Reusable Menstrual Cups – What You Need to Know

Toxic Shock Syndrome or TSS and Reusable Menstrual Cups – What You Need to Know

Recently a study was published entitled “Impact of currently marketed tampons and menstrual cups on Staphylococcus aureus growth and TSST-1 production in vitro” that has caused some waves in reusable menstrual communities.

There has been a lot of conclusion jumping and to make sure I have the facts straight, I purchased a copy of the article to read. Here’s what you need to know and how to prevent TSS with your reusable menstrual cup.

toxic shock syndrome tss and reusable menstrual cups

I first learned about Toxic Shock Syndrome in high school. A friend developed TSS from using a tampon and was hospitalized. At the time, we knew she was sick and even sent flowers, but did not quite understand how it happened or that her life was in danger. Later, she told us that she had left a tampon in for too long and that caused staph to grow and enter her bloodstream.

Toxic Shock Syndrome is a rare, but life-threatening condition that can happen when using menstrual products. It’s so feared because while rare, it can lead to death and has a sudden onset of symptoms that seem like the flu. Because of the flu-like symptoms, people with TSS don’t often seek treatment until symptoms are pretty bad and they have a higher chance of really serious medical consequences. (1)

What is Toxic shock syndrome

TSS is caused by the overgrowth of the bacteria Staphylococcus aureus that is often already living on your skin and in your nose. (1) This life-threatening illness is caused by toxins produced by some strains of staph bacteria, in the most recent study they used s.aureus strain ST20140321 (5) and staph has been linked to certain types of tampons, skin wounds and surgery.

As an FYI Symptoms of TSS include:

  • A high fever
  • Nausea and vomiting
  • A rash on your palms and soles that resembles sunburn
  • Confusion
  • Muscle aches
  • Diarrhea
  • Abdominal pain (2)

Staph is a bad bug.

TSS is not the only illness staph can cause. It’s also skin infections, food poisoning, septicemia, and septic arthritis. (2) Generally, it’s already living on your skin and doing things like washing your skin and cleaning surfaces is a good way to help reduce it and prevent infection. (1,2)

Staph is normally already present in your vagina, without causing harm. (1) When TSS develops, it’s from the bacteria growing and releasing toxins (TSST-1) that get into your bloodstream and some people are at more risk than others. (1,2) Generally, if you already had TSS once, you are at a high risk for getting it again. (1)

toxic shock syndrome tss and reusable menstrual cups

TSS and Reusable Menstrual Cup Study

The study published on April 20th, 2018 in the Journal of Applied and Environmental Microbiology reports that TSS, due to the toxin released from staph, can result from reusable menstrual cups as well as tampons.

The researchers tested 11 types of tampons made by Tampax, Nett, OB and Naturacare.

They tested 4 types of reusable menstrual cups by be’Cup and MeLuna.

The scientists attempted to make a laboratory environment that is similar to conditions in the vagina.

Keep in mind that this study was done using menstrual products, plastic bags, a substance used to grow germs and a warming and movement to simulate the human body after 8 hours. (5)

This study did not involve actual menstrual fluids or vaginas. It did not include real people or a huge sample of cups, a long time length or real menstrual fluid or environments.

For the bacteria to grow in your vagina it needs:

  • Right temperature
  • Staph germ to be present
  • Something to grow in and/or on
  • the right pH level
  • Oxygen (6)

How this went down. 

Reusable menstrual cups were purchased at a store, boiled per the company instructions. Then, they were placed in germ-free (sterile) plastic bags with sterile gloves and a Brain Heart Infusion which is a nutrient rich growth medium used by scientists for growing germs. (3) Brain heart infusion seen below.

BHI media

Some products were left alone with the growing solutions only in the plastic bag, others had the staph germ placed in the plastic bag with the menstrual product and germ growing solution.

Air was removed from the bags and they were warmed at 98.6 degrees Fahrenheit (normal body temperature)/37 degrees C.

The bags with the germ + growth solution + incubation/warming were shaken (200 rpm) for 8 hours. They later mention that some were not shaken.

They also grew the germ + growth solution by itself without a tampon or menstrual cup to see what happened referred to as the control.

Reusable menstrual cups were cut into sections with a sharp germ-free knife and put in the plastic bags and tested the same way.

Tampons were also tested. Both whole and taken apart.

toxic shock syndrome tss and reusable menstrual cups

The results

The scientists found that the reusable menstrual cups they tested grew the staph bacteria more than the tampons and the toxin TSST-1 that I mentioned above. They believe that this is because they put more air into the plastic bags with the cups “due to their shape.” (5)

There is no mention of chemicals in the tampons designed to prevent bacteria from growing however, I think the fact that some of the tampons grew less bacteria than the control suggests that something is there.

They did not say if they used a reusable menstrual cup fold, or what fold they used. I imagine they just placed them in the bags as-is without folding.

The larger models of the cups grew more bacteria, which they mention may be due to more air in the plastic bags. (5)

Frst, they mentioned that the silicone be’Cup has a higher toxin level (TSST-1) and staph growth than the Me Luna TEP cups. Meluna Cups are made from TPE and not from silicone.

The scientists say that they believe the ability of silicone to breathe, compared to TPE, may be the cause of this. They made sure this was true by looking at the sliced sections of cups as well. Because, when they used slices of the cups and made sure to get the air out, there wasn’t a difference between materials. (5)

There is no difference between the materials as first mentioned.

“…we were able to totally deflate the plastic bag fill with sections of cup and did not observed difference of TSST -1 production between cup anymore. Our results suggest that aeration like to the shape and volume of the cup more than composition of cup influences toxin production.” (p.14)

There are no typos there, that’s how it’s written. My correction program has it all red and lined.

What all of this actually means. 

This means that when you put a reusable menstrual cup in a plastic bag with the bacteria known to cause TSS syndrome, a substance designed to grow germs + air and warm it for 8 hours, shaken and unshaken, you can produce the toxin known to cause TSS.

That’s what we know from this. There were no vaginas. No menstrual blood. No real menstruators. This is a laboratory controlled scientific experiment with two brands of cups, 4 cups total and a handful of tampons.

Also important, air increased the growth of bacteria.

More time = more bacteria = more toxin. The bacteria grow in the menstrual blood & fluid inside of the cup. Emptying sooner is better because longer = more growth.

Water did not wash away the bacteria. I don’t think anyone was ever under that impression, washing with water is simply to clean off blood & fluid…not to kill bacteria. However, this proved that it did not remove all of the bacteria.

Cup wipes were not tested. I really wish they were.

Boiling the cup is the only way to kill bacteria that they tested. We already knew this.

I don’t think you can use this study to say that menstrual cups cause a higher risk of TSS than tampons because of it’s limitations. Not many cups were used, they put air in the bags and this was done in plastic baggies…not actual vaginas and on-purpose put in the bacteria with a bacteria growing formula to see if it grew. It did.

“We observed a slight increase of S. aureus growth and toxin production with menstrual cups, due to the introduction of a higher volume of air than that occurring with tampons in…” the lab setup. “Both intravaginal devices appear to be risk factors for the development of menstrual toxic shock syndrome and precautions should be advised.” (5)

Bottom line

I take this study with a grain of salt. I don’t think this tells us anything we didn’t already know. Wash your hands before inserting your cup. Boil your cup to kill germs. Menstrual cups do not prevent TSS.

Menstrual cups also don’t already contain Staph and not mentioned, possibly tampons contain a chemical to inhibit bacterial growth?

If you’re someone who’s prone to TSS or concerned, they recommend using two cups and boiling it each time you remove it so a boiled/totally clean cup is always ready to be used.

Also, longer wear = more growth if the bacteria is present because the menstrual blood is sitting in the cup longer. I empty my cup every few hours during the day anyway. The nighttime span would be my concern here…but it was before I read this study anyway and is also a concern with tampons because the bacteria grows in sitting fluids.

So what.

That was my thought after reading the study. So what? It’s a small study that grew bacteria in plastic bags filled with a menstrual product + bacteria growth fluid + bacteria that causes TSS. I’m not surprised they grew the bacteria and toxin.

It does remove any idea that menstrual cups somehow prevent the growth of TSS because they didn’t sterilize the liquid and bacteria when it was introduced. I never thought this anyway.

It’s food for thought, but I don’t see it as more than that. Super interesting, but I hope it’s done on a larger scale and they get some real menstrual blood and vaginal pH going next time.

  5. Nonfoux, L., Chiaruzzi, M., Badiou, C., Baude, J., Tristan, A., Thioulouse, J., Muller, D., Combaret, C. P., and Lina, G. (2018) Impact of currently marketed tampons and menstrual cups on Staphylococcus aureus growth and TSST-1 production in vitro. Appl. Environ. Microbiol. Accepted manuscript posted online 20 April 2018 doi:10.1128/AEM.00351-1  Retrieved from:



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