'Forever chemicals' found in tampon wrappers and period underwear, new study finds. Here's what you need to know.

There are a lot of period products in the market, but while pads, tampons, menstrual cups and period underwear are popular options, they don't usually publicly share their ingredients.

That led a research team from the University of Notre Dame to test more than 100 period products for fluorinated compounds, an indicator of potentially harmful per- and polyfluoroalkyl substances, or PFAS, also known as "forever chemicals." The researchers found that many products don't have PFAS. But some do — and in surprising places.

For the study, which will be presented Sunday at the American Chemical Society's fall meeting, the researchers cut out a small portion of each period product and analyzed it with with particle-induced gamma-ray emission spectroscopy. The researchers also tested the fluorine levels in the wrappers of single-use products, such as tampons and pads.

"In general, tampons didn’t seem to contain fluorine,” Alyssa Wicks, a graduate student at the University of Notre Dame and study co-author, said in a press release. “Same with menstrual cups and the layers of pads that come in contact with a person’s skin.”

But Wicks and the lead study author, Graham Peaslee, found that fluorine was detected in the wrappers for several pads and some tampons, as well as the outer layers of some period underwear. Some products had levels of fluorine of 1,000 to several thousand parts per million, which is considered a high concentration. (Wicks theorizes that the forever chemicals may be used to keep moisture out of the wrappers so the products stay dry and that, in the case of period underwear, PFAS may be used to keep blood from leaking onto a person's clothes.)

PFAS have been linked to a slew of serious medical conditions, and this news has raised some eyebrows. But how concerned should people be? Here's what you need to know.

Why are forever chemicals harmful?

Forever chemicals are a large group of synthetic chemicals that have been used in consumer products since the 1950s, per the National Institutes of Health (NIH). PFAS are used for a wide range of things, including keeping food from sticking to packages or cookware, making carpets stain-resistant and in firefighting foam.

PFAS have been tied to several serious health problems. "Exposure to PFAS has been linked to high cholesterol, diabetes, liver disease, decreased vaccine response, type 2 diabetes and breast, kidney or prostate cancers," Joseph Braun, a professor of epidemiology and director of the Center for Children's Environmental Health at the Brown University School of Public Health, tells Yahoo Life. They have also been linked to obesity and infertility.

The chemicals can build up in your body over time, and it's possible to take in more than you excrete, the NIH says. The Environmental Protection Agency issued health advisories earlier this year stating that PFAS are more dangerous to human health than previously thought. Those advisories also said that PFAS may cause health issues at lower levels than scientists initially believed.

"Given that PFAS remain in the body for years, prior PFAS exposure from tampons could remain in the body long enough to affect the developing fetus to increase the risk of low birth weight and preterm birth, or decrease vaccine response," Braun says.

What's unclear, though, is whether these PFAS leach from the wrappers onto the period products, Dr. Robert Laumbach, associate professor of environmental and occupational health and justice at the Rutgers School of Public Health, tells Yahoo Life. Small molecules in PFAS could potentially get into the air from the wrappers and other products and attach to the absorbent material in tampons, pads and period underwear, he says. "Whether that happens or not, we don't know," he adds.

How concerned should you be?

This isn't the first time PFAS have been detected in period products. Lab analyses conducted between 2020 and 2020 by Mamavation and Environmental Health News found that 48% of pads and panty liners contained PFAS, along with 22% of tampons and 65% of period underwear. Some of those products were also advertised as "organic," "natural" and "nontoxic," the researchers pointed out.

"Consumers should be very concerned to see yet another category of products that contains PFAS," Kaley Beins, a senior scientist at the Environmental Working Group, tells Yahoo Life.

But Laumbach says the concern is "somewhat relative," given that people can be exposed to PFAS in many different ways. "Having it in your drinking water, where we know it can get absorbed at certain levels, is on the high end," he says. "This is of concern, but where it is on that scale we're not sure, because of lack of knowledge."

PFAS on the wrapper of period products are "lower down on the concern scale," he says. But "this is another source of PFAS, and that's a potential concern."

Which products contain forever chemicals?

The study results haven't yet been published, and the researchers have not publicly called out any particular brands. However, the New York Times just published an analysis of 44 period products that was conducted by the same researchers.

While the Times also didn't give brand names in general, it did note that Thinx period underwear had some of the lowest levels of PFAS of the 10 pairs of period underwear the publication tested.

What should you do now?

This is tricky. In the absence of brand products, it's difficult to say what people should or shouldn't consider avoiding. And, as Laumbach points out, it's hard to know at this point how to interpret these results.

"Some period underwear and pads," Beins says, "seem to have levels that suggest intentionally added PFAS, so until more information is available, I would recommend using a tampon or menstrual cup over a pad or period underwear."

Emily Scarr, director of the public interest advocacy group Maryland PIRG Foundation, tells Yahoo Life that it's important for lawmakers to get involved. "The ubiquitous use of PFAS in consumer products has got to stop," she says. "Consumers shouldn't have to play an endless game of whack-a-mole to avoid these toxic chemicals. We need our state and federal leaders to stop the use of PFAS in consumer products completely."