Are any of our period products safe? - What we do and don’t understand about toxic shock syndrome

This article is an attempt to add my voice to the noise around the abysmal attention to women’s health. We do not have enough empirical evidence to confidently advise and protect women and girls from health complications associated with their menstrual cycle. This piece focuses on the occurrences of toxic shock syndrome associated with menstruation.

During their menstrual cycle, women are particularly vulnerable to infections via the vaginal membrane, this is also the case soon after giving birth.  Toxic Shock Syndrome (TSS) associated with a woman’s period is referred to as Menstrual Toxic Shock Syndrome (mTSS) It’s caused not by any period product but is an infection of a bacteria called Staphylococcus aureus (S. aureus).

Our bodies are very familiar with these bacteria, S. aureus permanently or transiently (intermittently) colonises the mucous membranes of most people (i.e. the nose, vagina and anus) Therefore, S. aureus is often already present in the vagina before the onset of the period.

The mechanism of infection during menstruation causes particular complications. It can result in the production of TSS-1, a toxin that causes multiorgan failure in about 95% of women with mTSS. The onset of organ failure is rapid and requires immediate attention from healthcare professionals. 1,2

How does the infection work?

Superantigens are released into our bloodstream by S aureus, these molecules are immunostimulatory (i.e. molecules that are able to stimulate the immune system) and bind onto the surface of our antigen presenting cells (APC’s) APC’s are an important type of immune cell. Most pathogens during an infection would first be engulfed and processed by an APC and their antigens presented on the surface of the APC. This usually allows the immune system to respond and start producing the correct antibodies to fight the infection.

Instead, the S aureus bacteria produces these superantigens that bind onto the surface of the APC directly.This essentially begins to trigger the immune system sending it into overdrive.

Then, this same superantigen that has bonded to our APC, also bonds directly onto our T cell cells (via the T cell receptor in the Vb region). The superantigen is now holding onto both cells. Bringing the T cells and APC’s into close contact for prologued periods of time forces the immune system into an overactive state called a cytokine storm. 3

The bacteria has hijacked our immune system into an overactive state that begins to destroy our organ tissues. The superantigens will start to dysregulate and manipulate whichever tissues it comes into contact with. The molecules travel through the bloodstream wreaking havoc, and quickly. 4

TSS can be causes by any of these superantigen producing bacteria, virus’ can do it to. They’re associated with not only TSS but cases of food poisoning, rheumatic fever and rheumatic heart disease. 5

Back to period products…

The specific conditions of the vagina during menstruation combined with poorly designed period products are what allow the rapid growth of this bacteria in our bodies.

The increased pH in the vagina associated with menstruation (from around 4.2 to 7.4) and oxygen and the presence of carbon dioxide in the vagina during menstruation both help aid the rapid growth of S aurus.  6

The materials used in tampons and pads have been shown to hold enough oxygen in vaginal cavity which encourages the growth of S aurus. The collection or pooling of the menstrual blood itself is also ideal for the growth of S aurus, which is why manufactures advise you to change the product regularly.

Polyester foam and super absorptive materials in tampons have been associated with a higher risk of mTSS. 100% cotton pads/tampons have been shown in some studies to lower the risk of TSS but not to eliminate it. 7

Increased vaginal irritation is also associated with mTSS, both tampons and menstrual cups have been shown to cause vaginal irritation. The cups in particular are shown to cause mucosal irrigation (irritation of the mucus membrane) The cups also hold the menstrual blood high up in the uterine tract for prolonged amounts of time. These conditions are thought to encourage rapid growth of S aureus. 8

The vaginal walls are very permeable and therefore any products being used in or around the vagina need to be carefully designed. There are herbicides used to grow the cotton that is used often in pads and tampons for example. The potential effects of this are unknown.  

There are major gaps in the work done to better understand period products and the risk of mTSS. After a public uproar in the 1980’s an FDA taskforce and other research bodies begun to pay some attention.

The research done by the FDA and other bodies had almost exclusively experimented using a saltwater solution instead of menstrual blood and a ‘synthetic vagina’ in tests. 9  The conclusions made by these studies can only be applied to far as a result of these limitations.

There is also a particular chemical called dioxin, a known carcinogen that is used in tampon products. The quantities used in tampon products are regulated by FDA standards but again, one may wonder how reliable these measures are.

Despite all of this, we should not be particularly anxious about mTSS, the occurrence of mTSS remains low and has gone down since the original research and regulations were established in the 90’s. mTSS effects around 1 in 100,000 menstruating people. However, there are 300 million people around the world having their period on any given day. 10

Any instance of mTSS remains very serious. The mortality rate of diagnosed mTSS is around 8%. Most affected are young women, the known average fluctuates between 12-18 years old depending on where you are in the world. Keep an eye out for any of the mentioned symptoms whilst using period products on your period.

One of the reasons for poor diagnosis of TSS are the ambiguous symptoms. mTSS may begin with flu-like symptoms during menstruation like fever, vomiting and diarrhoea as well as sunburn-like rashes and progressive dizziness upon standing.  A patient may also appear visibly appear unwell, pale, tired etc. Many of these symptoms are unhelpfully associated with ‘regular’ menstruation. If you are feeling unusually unwell, experiencing any of these symptoms and/or are concerned, please always seek out medical attention. 6

One reason that has been suggested for the relatively low occurrences of mTSS is that people are already colonised with TSST-1 negative strains in the mucous membranes and therefore appear to already be protected by the correct antibodies. 11

In summary, undoubtedly there is a need for more innovation in this area to create a solution that is proven to carry at least close to zero risk of life-threatening infection for people on their periods.

REFERENCES

1.        Ikebe, T., Ato, M., Kobayashi, K. & Watanabe, H. [Mechanism behind streptococcus toxic shock-like syndrome onset--immune evasion and bacterial properties]. Kansenshogaku Zasshi 83, 485–489 (2009).

2.        Parsonnet, J. et al. Prevalence of toxic shock syndrome toxin 1-producing Staphylococcus aureus and the presence of antibodies to this superantigen in menstruating women. J Clin Microbiol 43, 4628–4634 (2005).

3.        Ross, A. & Shoff, H. W. Toxic Shock Syndrome. StatPearls (2023).

4.        Herman, A., Kappler, J. W., Marrack, P. & Pullen, A. M. SUPERANTIGENS: Mechanism of T-Cell Stimulation and Role in Immune Responses. (1991).

5.        Davis, J. P., Chesney, P. J., Wand, P. J. & LaVenture, M. Toxic-shock syndrome: epidemiologic features, recurrence, risk factors, and prevention. N Engl J Med 303, 1429–1435 (1980).

6.        Schlievert, P. M. Menstrual TSS remains a dangerous threat. EClinicalMedicine 21, (2020).

7.        Pušić, T., Vojnović, B., Flinčec Grgac, S., Čurlin, M. & Malinar, R. Particle Shedding from Cotton and Cotton-Polyester Fabrics in the Dry State and in Washes. Polymers (Basel) 15, (2023).

8.        Mitchell, M. A., Bisch, S., Arntfield, S. & Hosseini-Moghaddam, S. M. A confirmed case of toxic shock syndrome associated with the use of a menstrual cup. The Canadian Journal of Infectious Diseases & Medical Microbiology 26, 218 (2015).

9.        Vostral, S. Toxic shock syndrome, tampons and laboratory standard–setting. CMAJ : Canadian Medical Association Journal 189, E726 (2017).

10.      Periods Don’t Stop for Pandemics – Neither Will Our Efforts to Bring Safe Menstrual Hygiene to Women and Girls. https://www.worldbank.org/en/news/feature/2020/05/28/menstrual-hygiene-day-2020.

11.      Kimber, I. et al. Toxic Shock Syndrome: Characterization of Human Immune Responses to TSST-1 and Evidence for Sensitivity Thresholds. Toxicological Sciences 134, 49–63 (2013).