When my son was a baby, I couldn’t get him to nap except in his bouncer seat. Sometimes I would sit on the floor rocking him with my foot for an hour—if I stopped, he would wake up and scream. These are not particularly joyful memories.

I would do a lot of things differently with him, sleep-wise, if I were doing it all over again. For one thing, I wouldn’t let him snooze in that bouncer. As I’ve recently learned, several popular children’s sleep products pose risks for babies before they turn 1, and infant deaths caused by some have been increasing. Experts warn that a handful of new, trendy products are potentially risky, too. In a study published in January, researchers found that 35 percent of ads in parenting magazines that showed cribs or sleeping babies, and half of all crib displays in retail stores and on store websites, depicted unsafe sleep environments. (The cribs shown on Pottery Barn’s baby bedding page, for instance, seem designed to give sleep-safety experts a heart attack.)

What’s more, a study published Monday in Pediatrics found that since 2003, the rate of nursery-related injuries leading to ER visits has increased by nearly one-quarter. So, if you’ve been letting your infant sleep in a rocker, swing, car seat, sling, DockaTot, or Babocush—or if you let him snooze in his crib with bumpers, blankets, or stuffed animals—it’s time to rethink that. (And, believe me, I know that when you’re constantly struggling to get a baby to sleep, any product that does the trick feels like a godsend. So how dare someone advise you to stop using it. But if you’re going to resort to using these contraptions, you at least need to know the risks.)

Let’s start with rockers, bouncers, swings, and car seats, which can be unsafe for sleeping babies for a few reasons. Before infants develop the strength to hold up their heads at around 4 months, they may slump over when placed in a seated position. With your baby’s chin resting against her chest, her airway can constrict and she can literally suffocate—what is known in the industry as positional asphyxia. In a 2015 study published in the Journal of Pediatrics, scientists reviewed all the infant deaths that took place in car seats and other sitting devices that had been reported to the Consumer Product Safety Commission between 2004 and 2008. They found that 48 percent of car seat deaths, and 75 percent of swing deaths, were due to positional asphyxia.

These deaths are rare—the study examined 47 cases—but even brief drops in blood oxygen can occur when young babies spend time in car seats or swings, and those can be a health concern, too. In a 2009 study, researchers at Harvard’s MassGeneral Hospital for Children as well as other institutions analyzed the blood oxygen levels of newborns when they were placed in cribs versus car seats and found that nearly one-quarter of the time that the babies were in car seats, their oxygen saturation levels (the ratio of oxygen-saturated hemoglobin to total hemoglobin in their blood) dropped below 95 percent, the cutoff for what is considered normal.

In cribs, on the other hand, oxygen saturation levels dropped below this cutoff only 6.5 percent of the time. These differences could be consequential, as small but regular drops in blood oxygen have been linked to developmental and behavioral problems later in childhood. As the authors of the study conclude, car seats should “be restricted to protection from injury and death in traffic accidents, and they should never serve as a replacement for a crib.”

As for the 52 percent of car seat deaths that weren’t caused by positional asphyxiation: Those were caused by the straps. If you’re not careful to secure the straps on a swing, rocker, or car seat when your baby is in it, she could get entangled in them and strangle. Likewise, if you secure the straps but don’t tighten them, “infants can wiggle out of them and strangle or fall,” explains N.J. Scheers, a statistical consultant and the former product manager of the CPSC’s Infant Suffocation Project.

This doesn’t mean that you shouldn’t ever use a car seat, by the way. Car seats are fantastic safety devices, and their use in vehicles saves far more lives than it risks. Indeed, a very important fact about the car seat deaths analyzed in that 2015 study is that 89 percent of them happened outside the car—basically, when parents let their kids sleep in a car seat at home or at day care. Car seats used in cars are safe for young babies when they are strapped in properly, no blankets are used, and the car seat is installed so that it reclines at about a 45-degree angle (which is in part to ensure that your baby’s airways stay open). At home, by contrast, unsecured car seats can topple over; straps aren’t used; infants are left unattended and sitting upright. Car seats, swings, rockers, and bouncers are also considered safe for babies who are awake and being monitored.

The best place for a baby to sleep, then, is a crib. But cribs can be unsafe, too—particularly when parents use crib bumpers or let babies sleep with blankets, pillows, or stuffed animals. The American Academy of Pediatrics has been warning against the use of crib bumpers since 2007, but it seems parents haven’t gotten the memo, because according to a recent study co-authored by Scheers, from 2006 to 2012, three times more deaths attributed to crib bumpers were reported to the CPSC than in previous time periods (though some of the increase could be due to better reporting). Babies can get lodged up against or under the bumpers and suffocate; they can become wedged between the bumper and the mattress; and they can choke on or be strangled by bumper ties. Some kids have also been injured after climbing on bumpers then falling out of their cribs, and there have been several reports of sewing needles discovered in bumper cushions, presumably left over from the manufacturing.

Bumper deaths and injuries don’t only affect young babies, either: In the study mentioned above, infants who were killed by bumpers were, on average, 4½ months old, while those who survived but sustained injuries were 7½ months old. In light of their dangers, Chicago banned the sale of crib bumpers in 2011, and in 2013 Maryland followed suit, though Maryland still allows breathable mesh bumpers and vertical bumpers that wrap around each crib rail. These are presumably safer, but studies have not yet confirmed that they are.

But bumpers serve a safety purpose, right? Decades ago, yes: Bumpers ensured that babies didn’t slip through crib slats or get their heads caught between them. But since the 1970s, regulations have required that slats be close enough together to prevent these accidents from happening. Crib bumpers probably do prevent some injuries caused by babies’ limbs getting entrapped between crib slats and heads getting bonked against the hard crib sides, but as the CPSC noted in a November 2016 statement, “we strongly believe that the risk of death from padded crib bumpers far outweighs any purported benefits.” In 2012, the CPSC adopted voluntary standards for crib bumper manufacturers to try to improve their safety. (These recommendations involve limiting bumper thickness to help prevent suffocation, but research suggests that even thin bumpers can cause problems, and no one knows how many bumper manufacturers actually follow these guidelines anyway.)

Products that hold babies in a particular position inside a crib are also unsafe. These include wedges marketed to help with reflux—both the FDA and the CPSC warn against their use as they have been linked to infant suffocation deaths—as well as infant “loungers” like the DockATot and the Snuggle Me, which can be safely used in some locations but not in cribs or bassinets. Although the websites for both products say that they should not be used in cribs, many parents use them there anyway, says certified pediatric sleep consultant Arielle Driscoll, founder of Expect to Sleep Again Sleep Consulting (and a friend). Another trendy new product I’ve been warned about is the Babocush, which is currently sold out worldwide due to high demand. It’s a cushion with a harness that babies lie on tummy-down, where they can be “soothed by gentle vibrations and a heartbeat.”

Soothed babies often become sleeping babies, though, and the American Academy of Pediatrics is pretty clear about the fact that tummy-down sleeping increases the risk of Sudden Infant Death Syndrome. The Babocush website points out that babies should not be allowed to sleep on it, but this warning only appears as a response to the 16th question on its FAQ page—and confusingly, some pictures on its website and Facebook page feature babies with their eyes closed, seemingly asleep. “The terrifying thing about many of these products is that if you read the fine print, you’ll see that they should only be used in very specific ways or shouldn’t be used for sleeping at all,” Driscoll says. “There needs to be better education for parents around safe sleep and clearer warnings from companies about how to safely use their products.”

Obviously, plenty of parents have used bumpers, bouncers, swings, car seats, blankets, and baby loungers inappropriately, and their babies have survived. Indeed, the risk posed to any one baby by misuse of these products is likely very small; according to Scheers’ study, for instance, the CPSC got reports of only 23 bumper-related deaths from 2006 to 2012. Yet reported deaths are likely a vast underestimate of the true prevalence, Scheers notes. Bumper-related deaths recorded by the CPSC do not always overlap with deaths recorded in other national databases, which suggests that the databases are not exhaustive. The CPSC gets its infant death data from death certificates it collects from each state, but if the deaths are not properly coded or labeled, they won’t get counted. “If bumpers weren’t mentioned—that is, the death certificates just said ‘suffocation’—then a word search for ‘bumpers’ wouldn’t find the deaths,” she explains.

The other thing about these deaths is that they are “completely preventable,” Scheers says. Sometimes we have to take risks out of necessity; we can’t just stop using cars to eliminate motor vehicle accidents. But there’s little cost associated with, say, not using blankets. I’ll admit, if I stopped using a rocker for my son’s naps, the cost may well have been a temporary loss of my sanity. And parental sanity is important. So, if you are going to let your child sleep in a swing, rocker, car seat, or other sitting device, take precautions: Always strap your baby in and tighten the straps; don’t use blankets or pillows; and don’t leave him unattended. If, on the other hand, you don’t want to take any unnecessary risks, the solution is quite straightforward, Driscoll says: “The safest way for a baby to sleep is on her back with nothing but a fitted sheet.”