{"id":415750,"date":"2026-05-07T05:49:15","date_gmt":"2026-05-07T05:49:15","guid":{"rendered":"https:\/\/www.newsbeep.com\/nz\/415750\/"},"modified":"2026-05-07T05:49:15","modified_gmt":"2026-05-07T05:49:15","slug":"siouxsie-wiles-menstrual-cups-are-a-great-invention-but-how-safe-are-they","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/nz\/415750\/","title":{"rendered":"Siouxsie Wiles: Menstrual cups are a great invention. But how safe are they?"},"content":{"rendered":"<p>Menstrual cups are a game-changer in terms of reducing waste, but only a handful of contradictory studies, carried out under artificial conditions, have been done on their safety. Siouxsie Wiles wants to change that \u2013 but needs your help.<\/p>\n<p>Menstrual cups are an ingenious invention, a reusable device that\u2019s inserted into the vagina to collect period blood. Once full you just empty it, give it a wash*, and pop it back in. It\u2019s both a cheaper and more environmentally friendly way of dealing with periods than using tampons and pads. Here are some eye-watering statistics for you. In 2023, people in New Zealand spent $79 million on disposable menstrual products, equating to an estimated 355 million units, each taking anywhere from 500 to 800 years to decompose.\u00a0<\/p>\n<p>But, despite first hearing about them in the early 2000s, I\u2019ve never been able to bring myself to try a menstrual cup. As a microbiologist, I couldn\u2019t get over my niggling fear of biofilms. What\u2019s a biofilm, you ask? It\u2019s when microbes exude a sticky matrix that allows them to stick to surfaces and form a little community that\u2019s protected from the elements, including our immune system and antimicrobial drugs like antibiotics. Something like 65-80% of all infections are related to biofilms.<\/p>\n<p>The study that started it all off<\/p>\n<p>I didn\u2019t give menstrual cups much more thought until 2018 when a journalist called asking me to comment on a <a href=\"https:\/\/journals.asm.org\/doi\/10.1128\/aem.00351-18\" target=\"_blank\" rel=\"nofollow noopener\">new study<\/a> suggesting menstrual cups might be riskier than tampons when it came to toxic shock syndrome (this is a rare but very nasty infection that can be deadly).\u00a0<\/p>\n<p>He sent me the paper, and I read how the researchers had put menstrual cups and tampons in plastic bags, filled the bags with bacterial growth media, added the bacteria that causes toxic shock, sealed the bags, and then shaken everything at 200 revolutions per minute in an incubator. After eight hours they tested how well the bacteria had grown and how much toxic shock toxin was produced.\u00a0<\/p>\n<p>More toxin was produced in the bags that contained the menstrual cups compared to tampons. Conclusion: cups are riskier than tampons.<\/p>\n<p>My first response to reading the paper was WTF?! In what way is a menstruating vagina like a bag of bacterial growth media shaking more vigorously than the most exuberant belly dancer?! So, I did a quick search of the scientific\/medical literature, and it turns out this was only the second study of its kind. The first was published in the 80s when menstrual cups were made of a different material.<\/p>\n<p><img alt=\"\" src=\"data:image\/gif;base64,R0lGODlhAQABAIAAAAAAAP\/\/\/yH5BAEAAAAALAAAAAABAAEAAAIBRAA7\" decoding=\"async\" data-nimg=\"responsive\" style=\"position:absolute;top:0;left:0;bottom:0;right:0;box-sizing:border-box;padding:0;border:none;margin:auto;display:block;width:0;height:0;min-width:100%;max-width:100%;min-height:100%;max-height:100%\"\/>Menstrual discs<\/p>\n<p>In other words, a product widely advertised as \u201csafe\u201d didn\u2019t seem to have any published evidence to back up that claim. So that got me thinking. Could we investigate whether bacteria can stick to menstrual cups under conditions that mimic the menstruating vagina and how cups are typically used? (Sticking is the first step needed for infection.) I had a great student, Aimee, start doing some experiments.\u00a0<\/p>\n<p>And then the pandemic happened.\u00a0<\/p>\n<p>As we went into lockdown, Aimee pivoted to a new project that didn\u2019t need access to a lab. And that was that. In the years since, I\u2019ve been a bit distracted and didn\u2019t give the project any more thought. Then about 18 months ago, another lab member asked if I was ever planning to restart the menstrual cups project. Surely it\u2019s all been done by now, I thought. I did another literature search to see what had been published in the intervening years.\u00a0<\/p>\n<p>A handful of contradictory studies\u2026<\/p>\n<p>I think it\u2019s safe to say that 2018 study was a bit like kicking a hornet\u2019s nest. Over the next few years, a flurry of studies were published, including some by Procter &amp; Gamble, which manufactures the Tampax brand of tampons and the Tampax menstrual cup. They concluded their menstrual cups are safe when used as instructed. But another independent study concluded there was cause for concern.\u00a0<\/p>\n<p>So no solid conclusion either way. And again, all the studies were done under pretty artificial conditions. And used different cup brands.<\/p>\n<p>In the meantime, though, at least one cup has come onto the market, <a href=\"https:\/\/bfreecup.com\/collections\/all-products\/products\/bfree-cup-size-1\" target=\"_blank\" rel=\"nofollow noopener\">bfree<\/a>, that specifically says it\u2019s made with an antibacterial coating. I\u2019m clearly not the only one worried about infection risk. But what about all the other cups on the market?\u00a0<\/p>\n<p>So, what\u2019s our project?<\/p>\n<p>We\u2019re asking the important question: how well do microbes stick to cups and discs under conditions that mimic the menstruating vagina? That means thinking about pH, oxygen levels, shaking speed, what nutrients are available, and adding blood. It seems hard to imagine, but almost all the lab studies done to date didn\u2019t involve blood!\u00a0<\/p>\n<p>Published studies have also focused on the toxic shock bacterium, so we want to include the microbes that cause urinary tract infections, thrush and vaginosis. Just because they aren\u2019t as deadly, doesn\u2019t mean they aren\u2019t important!\u00a0<\/p>\n<p>We also want to test a wide range of cups and discs. There are loads on the market. Thick. Thin. Hard. Soft. Textured. Smooth. Silicone. TPE. Rubber. Do microbes stick to them all the same? And what about a $3 cup from Temu or Amazon versus a $40 branded one? Does price matter?<\/p>\n<p>Why we\u2019re crowdfunding<\/p>\n<p>Funding for research in Aotearoa New Zealand has been bad for a long time, with success rates well below other countries we like to compare ourselves to. And things have only gotten worse. It\u2019s dire. On top of that, funding women\u2019s health projects is even more difficult. A <a href=\"https:\/\/www.mckinsey.com\/industries\/healthcare\/our-insights\/unlocking-opportunities-in-womens-healthcare\" target=\"_blank\" rel=\"nofollow noopener\">2021 analysis<\/a> revealed that just 1% of global healthcare R&amp;D spend is invested in women\u2019s health conditions beyond cancer.\u00a0<\/p>\n<p>I\u2019ve spent more than 18 months applying for funding. In the meantime, we\u2019ve been doing what little bits we can, thanks to a small grant-in-aid from Istar and donations from members of the public and from me.\u00a0<\/p>\n<p>More than 10 rejected funding applications later, and crowdfunding is all I have left. The timing sucks, with the cost-of-living crisis only getting worse, but I think this project is too important not to do.\u00a0<\/p>\n<p>So, I\u2019m trying to raise $150,000, which will just about cover our expenses for a year. I\u2019m hoping enough people have a few dollars to spare, either as a one-off or monthly donation, to get us to our target. Donations over $5 are tax-deductible, so individuals and companies in NZ can claim back one-third of the donation amount.<\/p>\n<p>Shouldn\u2019t the manufacturers be funding studies?<\/p>\n<p>This is an excellent question and I have mixed feelings. On the one hand, yes, they should be ensuring their products are safe to use. But on the other hand, there is a clear benefit to studies being independent of the companies. That way, they\u2019ll be free of any real or perceived bias\/influence and able to fully report their findings.\u00a0<\/p>\n<p>So if you agree this study and our independence is important and you can afford to support us, please <a href=\"https:\/\/support.auckland.ac.nz\/mcr\" target=\"_blank\" rel=\"nofollow noopener\">donate here<\/a>.\u00a0<\/p>\n<p>If you can\u2019t afford to donate, I totally understand. You can support us by sharing this post and the donation link as far and wide as you can \u2013 with friends, family, work colleagues, and using social media.\u00a0<\/p>\n<p>Together we can give menstrual cup and disc users important information about the products they use.\u00a0<\/p>\n<p>*Don\u2019t even get me started on the differences in washing recommendations. Studying those is also on my wish list!<\/p>\n","protected":false},"excerpt":{"rendered":"Menstrual cups are a game-changer in terms of reducing waste, but only a handful of contradictory studies, carried&hellip;\n","protected":false},"author":2,"featured_media":415751,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[156,213790,213791,101473,111,139,69,213792,147],"class_list":["post-415750","post","type-post","status-publish","format-standard","has-post-thumbnail","category-entertainment","tag-entertainment","tag-menstrual-cups","tag-menstrual-products","tag-menstruation","tag-new-zealand","tag-newzealand","tag-nz","tag-period-waste","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/415750","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=415750"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/415750\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/415751"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=415750"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=415750"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=415750"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}