One of the most heartbreaking frustrations for new parents is that moment when you can’t figure out why your baby is crying. When he’s fed, rested, dry and healthy, what else could possibly be wrong? It’’s not like any of us would ever let something sharp anywhere near the baby, so something poking him is out— but he could be in pain for a more sneaky, surprising reason. As Mommyish and Today report, one of the most dangerous things for babies is . . . stray hairs?

It sounds crazy, but it’s true. Stray hairs can wrap themselves around your baby’s toes, forming what’s known as “hair tourniquets” that cut off blood supply, slice through skin, and, of course, cause immense pain an infant can’t possibly communicate. While hair might seem soft, it actually has a high tensile strength – the amount of force required to pull something – and once it’s wrapped and knotted, it’s difficult to undo and rare for it to unwrap itself naturally. Today elaborates:

Parenting and youth development expert Dr. Debi Gilboa told TODAY.com that a hair tourniquet is one of the many risks young children face, but not many parents know about it. “This is something all pediatric interns are taught to look for when baby or a preverbal toddler is inconsolable,” she said. A hair tourniquet happens because a lot of parents have long hair and babies tend to grab it or a piece of it can end up in places like their diaper or sock without you [even] noticing. “If you feel like your child is behaving in a way that’s unusual, pay attention to it. You’re usually right,” Gilboa said. “A hair tourniquet is a great thing to check for and it’s not hard to spot. There’s not really any way to prevent it, but they’re not that hard to remove. Use something like a bobby pin, so it’s thin and not sharp, slide it between the hair and the skin and it pops right off. If you feel uncomfortable call your doctor.”

Why are toes such a particular problem? Because they’re more often covered, especially in colder months, and hairs can easily become stuck in sock fibers. (Diapers can be a problem too, so check in those areas too, especially if your baby is a boy.) While you’d likely notice one hanging around a finger, you wouldn’t see one around a toe— until your baby starts crying.