In an Instagram post published shortly before she gave birth, an enthusiastic Arkansas mom shares her baby boy’s picture-perfect crib. Inside sits a blue onesie, a grey winter hat embroidered with her son’s name, a binkie clip made of neutral wooden beads, a sonogram picture, and two neutrally toned knit stuffed animals. A matching blue throw blanket sits over the side of the crib, but the caption zeroes in on the least interesting part of the photo: the bare white mattress. “This mattress is 100% breathable AND 100% washable which is crazy to me,” she says, tagging the brand of mattress. “I know I’ll have such a better peace of mind once we transition … to his crib knowing he can literally breathe through his mattress if he happens to roll over while sleeping.” She offers a discount code (necessary, since breathable mattresses can be over three times more expensive than standard mattresses), giving her 35,000 followers a chance to get in on the breathable crib mattress peace of mind too.
There’s just one problem: The evidence of safety benefits is largely absent. That peace of mind might well be illusory.
SIDS is one of the deadliest issues infants face, killing approximately 3500 children per year. The CDC and American Academy of Pediatrics have answered with clear and important advice: Put your child to sleep on their back in a crib with nothing in it. Empty cribs and back sleeping is a proven way to lower the chance of SIDS occurring. Period.
Still, a number of companies have the commendable intention of solving SIDS with products. And products like breathable mattresses seem like a very promising solution. The problem? “There is no evidence that these mattresses make any difference,” says Dr. Benjamin Hoffman, chair of the American Academy of Pediatrics Council on Injury, Violence and Poison Prevention.
That’s not to say the idea of a breathable mattress doesn’t make sense. After all, there’s still a lot we don’t know about SIDS. Most crucially, the exact mechanism of SIDS — what causes so many babies to die in their sleep — remains unclear. One theory is rebreathing. The idea is that babies end up with an object covering their face, creating a pocket of air, forcing them to repeatedly inhale the carbon dioxide they’re exhaling, depriving them of oxygen and causing carbon dioxide to build up in the body. “There hasn’t been any definitive evidence that that’s what’s going on, but it seems to makes sense,” says Dr. Rachel Moon, Harrison Distinguished Teaching Professor of Pediatrics and Division Head at the University of Virginia School of Medicine and chair of the American Academy of Pediatrics Task Force on Sudden Infant Death Syndrome.
This is what makes the idea of a more breathable mattress so appealing. On its surface, it too “makes sense,” says Dr. Umakanth Katwa, Attending Pulmonologist and Director of the Sleep Laboratory at Boston Children’s Hospital and professor at Harvard Medical School. He points to simulations done by mattress companies that show some mattresses can disperse carbon dioxide more quickly. Theoretically, this would increase the amount of time it takes for carbon dioxide levels to become lethal, giving babies more time to wake up and move. Katwa explains the importance of this, saying that babies who die in these kinds of situations tend to have what’s called an “arousal defect” which prevents them from waking up even when they’re not getting enough oxygen. “There is a defense mechanism when we sleep that if your carbon dioxide rises, you wake up and you turn your head on the side or you roll,” Katwa says. “Babies with SIDS not only need to suffocate, but they need to have the abnormal arousal response. That means even though they are rebreathing their carbon dioxide, what happens is the brain doesn’t wake up. So that means they cannot lift the head, turn on the side, or roll over.”
But exactly what breathable technology is safest is up in the air. “There is just no science around the ‘breathability’ and risk for sleep-related death,” Hoffman says. Moon says there was one study, decades ago, on breathable mattresses that are no longer available, and the only ones that were found effective in reducing carbon dioxide levels were mattresses with fans in them.
As such, each company has a different approach to making mattresses more breathable. Nook’s mattresses feature hollow cut-outs within that they call “air channels.” Newton makes their mattresses out of a spongy, food-grade polymer that they say is “90% air by volume.” Breathe Easy mattresses are essentially hammocks made of medical-grade polyester suspended over hollow plastic boxes, purportedly providing “air permeability 330 times higher than a conventional mattress.”
To add to this, the scenario that these mattresses address, in which babies roll onto their stomachs and suffocate on their mattress, isn’t where the biggest risk of SIDS lies. It could happen, Moon says, but “what seems to happen more is that they roll over on their stomach and get stuck in soft bedding or a bumper. It’s unusual when they roll over that there isn’t something else involved.” So if a parent puts their child to sleep on a breathable mattress in a crib with a blanket, pillow, or bumper, they’re defeating the purpose. (And if Instagram is any indication, there are plenty of parents doing this). In a 2019 AAP study, 69 percent of infants who suffocated accidentally did so on soft bedding like a blanket or pillow. Of that soft bedding, 34 percent were blankets, 23 percent were adult mattresses, and 22 percent were pillows. Most often, babies who suffocated were in adult beds, and not placed on their backs, as recommended. Crib mattresses were never mentioned.
And that’s just deaths caused by suffocation. In 2018, only 23 percent of Sudden Unexpected Infant Deaths in the US were caused by suffocation — 77 percent remain unexplained.
Another scenario targeted by mattress companies is overheating, which the AAP says increases the risk of SIDS. Katwa says that the inability to regulate temperature might be a symptom of that same arousal defect that prevents babies from waking up even when they’re getting insufficient oxygen. But there’s too little data on how temperature plays into SIDS for the AAP to recommend a specific room temperature, let alone make recommendations about what mattress covers are best. Parents’ best bet, per the CDC, is to dress babies in a single layer and watch out for sweating and a hot-to-the-touch chest. Katwa adds that of course babies shouldn’t sleep on surfaces that reflect heat, like plastic.
While Katwa seems optimistic about the utility and theoretical science behind breathable mattresses, especially for at-risk babies (those who are premature, have a sibling who died of SIDS, live in a house where someone smokes, or are diagnosed with sleep apnea) he stops short of recommending one brand, since the AAP doesn’t endorse their effectiveness. “If I’m writing a prescription, I know I can take exactly this medicine and this dose. But if I’m giving the recommendation, go and buy a breathable mattress…I’m relying on the parents to go and do shopping on the Internet and figure it out for yourself,” Katwa says. “If it is not a rigorously controlled trial or some sort of study, I cannot prescribe them. That is a challenge as a physician.”
The bottom line is that, for now, parents should stick to what we know works. This means laying babies down to sleep on their backs, on a firm mattress, with no soft bedding, blankets, pillows, bumpers or toys, and no gaps between the mattress and the crib decreases SIDS. Breastfeeding, not smoking, staying up to date with vaccinations, using a pacifier (but not one attached to clothing) and having the baby sleep in the same room as their parents, but not in the same bed, is also associated with reduced risk. But breathable mattresses? They won’t hurt, but there’s also no evidence they make sleep safer. If you’re looking for peace of mind, stick with what works. And take solace in the time that the SIDS risk drops off after 6 months, and is nearly entirely absent by a baby’s first birthday. By then, you’ll have plenty of other things to worry about.