Could your yoga mat be affecting your fertility?

Yoga classes are meant to help you forget it all: It’s a Zenned-out space where thinking about your to-do list or work drama isn’t allowed. But according to a new study, there might be a hidden danger to spending all that time on the mat—which could cause a whole lot of stress and heartbreak down the road.

When researchers analyzed urine samples from 211 women who were undergoing in vitro fertilization (IVF), they found those with a higher concentration of a common flame retardant in their urine were 40 percent less likely to become pregnant or have a successful birth.

Flame retardants are used in polyurethane foam in many different common household items, including (possibly) the yoga mat you spend hours a week on.

So, what are these chemicals that are making it harder for women to get pregnant? Organophosphate flame retardants (PFRs) are used in polyurethane foam in many different common household items, from sofas and baby toys to (possibly) the yoga mat you spend hours a week on. And considering the study detected the chemicals in more than 80 percent of participants, it’s a serious issue.

“Couples undergoing IVF and trying to improve their chances of success by reducing their exposure to environmental chemicals may want to opt for products that are flame-retardant free,” senior author Russ Hauser, professor of reproductive physiology at Harvard T.H. Chan School of Public Health, said in a press release.

Since it doesn’t take much effort for PFRs to get into your system—whether through direct contact or simply breathing them in—pay close attention to what your mat is made of. Spend your money on an eco-friendly and sustainable product that doesn’t contain PVC, EVA, plasticizers, foaming agents, or any other synthetic rubber or chemical additive. Instead, look for mats that say they’re made from non-toxic TPE, jute fiber, or all-natural rubber so you can get your downward dog on worry-free.

If you’d rather skip out on yoga mats altogether, give horseback yoga a try. Or, get some inspiration from this woman who’s turning the world into her yoga mat.