![\"\"](\"https:\/\/images.newscientist.com\/wp-content\/uploads\/2024\/07\/10143640\/SEI_212241295.jpg\")
<\/div>Existing menstrual pads can lead to leaks<\/p>\n
Vittoria\/Alamy<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/p>\n
Menstrual products that cause blood to form a solid gel-like substance, rather than be absorbed, seem to reduce the risk of leaks.<\/p>\n
Bryan Hsu<\/a> at Virginia Tech and his colleagues wanted to find a way of reducing the leaks that often occur with conventional menstrual pads and cups.<\/p>\n They tested various types of biopolymers, naturally occurring chain-like molecules, with pig blood<\/a> to find one that increases its viscosity. The team used pig blood because it is easier to access than human menstrual blood but has similar properties, says Hsu.<\/p>\n A type of biopolymer called alginate was mixed with glycerol, a sort of alcohol, and then exposed to blood, which created a gel-like substance. \u201cThe alginate powder alone, when blood is added, doesn\u2019t absorb the blood very well,\u201d says Hsu. \u201cIt has kind of like an unstirred-cocoa-powder-in-milk consistency with a dry core. We added the glycerol to the alginate to improve its ability to absorb blood.\u201d<\/p>\n To put the combination to the test, the researchers added 8 millilitres of blood to an artificial vagina, simulating a period. They made this bleed onto a standard menstrual pad where the internal absorptive material had been removed and replaced with gauze coated in the alginate-glycerol mixture. One hour later, this pad had retained more blood than when the vagina bled on standard pads that hadn\u2019t been altered.<\/p>\n <\/p>\n In another part of the experiment, five people removed menstrual cups filled with blood from the synthetic vagina but were blinded to whether they were lined with the alginate-glycerol mixture or not. The former led to almost no spillage, whereas the latter consistently resulted in spills.<\/p>\n Alginate is naturally found in algae and is sometimes used in wound dressings. \u201cAlginate likes to form intermolecular cross-links by using calcium, and blood has calcium,\u201d says Hsu. \u201cWe think these polymers initially absorb the blood, and as they dissolve, they start to form these cross-links, which eventually gels the blood.\u201d<\/p>\n