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Crib Mattress 101: Ultimate Crib Mattress Guide

Ask any parent-to-be the hardest thing to shop for, and chances are most of them will give the same answer: the crib mattress!

When I was pregnant with our daughter, I hated the waiting. Pregnancy wasn’t my bag, and to keep my mind off of what seemed like a never-ending wait, I threw myself into research. Whenever I found a spare moment and a bit of energy (a rare combo, to be sure), I combed the internet for the best baby products and added them to our shopping list.

And you know what I realized?

A Crib Mattress is One of the Hardest Things to Buy for New Parents

When it came to onesies, strollers, and diapers, I asked friends and was able to make decisions fairly easily.

But when it came to choosing my baby’s mattress, I found myself stuck.

Why?

Turns Out Buying a Crib Mattress is Scary

The Internet is full of warnings of the dangers hidden in your baby’s mattress…

Toxic gases and fire retardants that will harm your baby and the planet.

Killer mattresses that will suffocate your baby (and also breathable mattresses that apparently won’t).

Hidden mold reservoirs that will result in lifelong asthma and breathing difficulties.

The more I read about this essential item, the worse it got. And the deeper I went into the rabbit hole of research.

Choosing the Right Crib Mattress is an Important Decision

Babies spend about 12 hours per night sleeping in their cribs. 

Add in a few naps throughout the day, and many babies spend more than half of each 24-hour day in their crib. 

While most moms and dads know this, research backs it up: very young infants sleep and average of 17 hours per day. Older babies and toddlers sleep for 13 to 14 hours within a 24 hour period.

Sleep is a Time for Development, Not Damage

For infants and toddlers, teenagers and seniors, sleep is a universal need. Just as moms and dads need enough sleep, so do babies.

Sleep keeps adults healthy. But for babies, it’s a key part of their development into thriving, healthy children. 

Here’s what just some of the evidence has to say about the importance of sleep for babies:

  • Sleep is a key for very young babies’ ability to learn. Sleep facilitates brain development and maturation, and allows babies to explore the world in increasingly sophisticated ways (source).
  • Sleep plays a key role in babies’ memories. Through sleep, babies can consolidate information they experienced while awake (source). 
  • Babies keep learning while they sleep! Evidence suggests babies process sensory stimuli and learn about their environment…even when they’re snoozing (source). 
  • Better nighttime sleep is correlated with higher cognitive scores in babies (source).
  • Babies who sleep better have been found to be more approachable and adaptable (source). 
  • Sleep helps babies manage and respond to stress (source), such as being briefly separated from their moms or being prevented from playing with a toy. 
  • Good sleep in babies helps prevent obesity and too much weight gain in young children (source, source).  

Add to that, sleep plays a key role in our health at a cellular level. Researchers have found that, during sleep, our bodies remove potentially toxic waste products from our brains. And it’s also key to neuroplasticity – our brain’s ability to adapt. 

According to Johns Hopkins Medicine:

Depression, seizures, high blood pressure and migraines worsen. Immunity is compromised, increasing the likelihood of illness and infection. Sleep also plays a role in metabolism: Even one night of missed sleep can create a prediabetic state in an otherwise healthy person.

Put simply, sleep is a time for your body – and your baby’s body – to recover from the environmental stressors of the day. It’s a time to detoxify, not deal with even more chemicals. 

And as parents, it’s our job to support a healthy sleep environment.

Unfortunately, Crib Mattresses are a Source of Harmful Chemicals in the Home

Unfortunately, the products we bring into our home can be a source of chemical exposure. While not all chemicals are harmful, many of them are. Personal care products, cleaners, containers, bedding, and baby and childrens’ products such as car seats, toys, and crib mattresses, can all contain chemicals that are harmful to our kids’ health and the environment.

Toxic Chemicals in Crib Mattress Filling Material

Polyurethane Foam

Polyurethane foam is one of the most common crib mattress components (and adult mattresses, too).

To make polyurethane foams, manufacturers react diisocyanates (methylene diphenyl diisocyanate [MDI] and/or toluene diisocyanate [TDI]) with polyols and water. It may also contain other chemical catalysts, blowing agents and flame retardants.

If your eyes glazed over a bit here, try to stay awake.

Flexible polyurethane foam is in a lot of your baby’s gear – including pieces she spends the most time with. We’re talking her crib mattress, car seat, nursing pillow, and more.

In “normal” flexible polyurethane foam (as opposed to plant-based foam), both the polyols and the isocyanates are petroleum-based.

In other words, it’s made from non-renewable resources. 

Besides being environmentally problematic, polyurethane foam can also be problematic for your baby’s health. If manufacturers use excess TDI, they can remain in the foam as unreacted isocyanates

TDI is a probable carcinogen and the USEPA notes that exposure to isocyanates can cause asthma; lung and skin damage; respiratory problems; and eye irritation.

Our Grade: Fail (avoid if you can)

Polyurethane Foam Deserves to Fail

If possible, avoid buying products for your baby that use polyurethane foam. Choose healthier alternatives like coconut coir, natural latex, organic wool, and unbleached organic cotton. If you don’t have a choice, look for products that are Greenguard Gold certified, and those that use CertiPUR-US certified foam.

Plant-Based Foam or Soybean Foam

Plant-based foam is foam in which some or all of the polyols used in the foam come from plant sources. Soy is the most commonly used plant in creating foam, which is why you’ll most often see it marketed as soybean foam or soy foam. 

Where as petroleum-based polyols can be replaced with plant-based polyols, diisocyanates cannot be. Even in plant-based foams, therefore, a considerable portion of the raw ingredients are petroleum-based.

Plant-based foam is likely better for your family and the environment, but marginally so. While it’s often marketed as an environmentally-friendly solution, we think there are far better alternatives, including natural latex, coconut coir, organic wool, and unbleached organic cotton.

Our Grade: Fail (avoid if you can)

Plant-Based Foam is Mostly Greenwashing

Soybean foam, soy foam, plant-oil foam – from what we can tell, it’s all a different way of saying the same thing. And at the end of the day, “foam” is the most important word. If you can, avoid plant-based foam. And if you can’t, look for products that are Greenguard Gold certified as well as those that are CertiPUR-US certified.

Polyethylene Terephthalate (PEET or PET)

Polyethylene terephthalate is a food grade plastic derived from hydrocarbons. 

When used in food and other packaging, it’s most commonly known as PET or PETE, and is identifiable by the #1 recycling symbol. When used as a textile, it’s known as polyester. 

PETE is generally considered to be one of the “safer” plastics available, and leading health authorities agree PETE is generally safe.

However, it has also been found to leach antimony (a possible carcinogen used as a catalyst during manufacturing) into bottled water. A number of studies have also found polyester clothing can expose wearers to antimony. 

From an environmental perspective, PETE is not biodegradable and is energy intensive to manufacture. However, it is recyclable, and very lightweight, which means it requires less energy during shipping. 

Studies investigating the relationship between SIDS and antimony have shown no link between the two. 

Put succinctly in the Journal of Environmental Monitoring:

“Antimony, which is normally present in domestic environments, has also been studied as a possible cause of cot death syndrome (SIDS) but extensive investigations have not confirmed this.”

Our Grade: Okay (Likely Okay for Health; Not Great for the Planet)

PET Makes the Grade (But Still isn’t Awesome)

While PET(E) is probably a safe crib mattress filling for your baby, it’s made from a non-renewable resource. If you purchase a crib mattress that uses PETE, look for one that uses recycled PETE, thereby helping to postpone the plastic’s introduction to our landfills and giving it a second lease on life.

Harmful Chemicals in Crib Mattress Waterproofing

Anyone who’s had a baby or young child knows how often middle-of-the-night accidents lead to middle-of-the-night clean-ups.

And because manufacturers understand the need to protect the inside of the mattress against urine and – ahem – other – messes, it’s long been the wisdom to use waterproof covers and layers in crib mattresses. 

Some crib mattresses are enveloped entirely in a waterproof cover, while others make use of a waterproof crib mattress pad or waterproof layer near the surface of the mattress.

With benefits of waterproofing, come some major drawbacks for your little one’s health. This is primarily because of the chemicals and materials used to achieve a waterproof crib mattress.  

Polyvinyl Chloride (PVC), Phthalates and Phthalate Alternatives

PVC, more commonly known as vinyl, is a popular choice for waterproof crib mattress covers.

And one of the major problems with PVC is the phthalates (and phthalate alternatives) that come with it. 

Without phthalates, PVC is a hard, rigid plastic. By adding phthalates and other plasticizing chemicals, manufacturers transform that rigid plastic into one that’s soft and pliable – like your raincoat, shower curtain, or inflatable plastic toys. 

The problems with phthalates are many. They can vaporize and off-gas into the air in your home. They can also “disconnect” from the plastic they’re added to and attach to household dust. Babies (all of us, in fact) can also absorb phthalates through their skin. 

Phthalates and their alternatives come with a number of demonstrated and suspected nasty health and developmental effects. 

They’re known endocrine disruptors and are suspected to contribute to endocrine diseases such as breast cancer and obesity, are correlated with asthma, neuroatypical disorders such as autism, low IQ, male reproductive development issues and more.

While some phthalates are banned in the United States for use in children’s toys and care articles, as well as some banned from children’s toys that can be placed in a child’s mouth, others are still permitted. 

Further, with the ban on some phthalates, there’s been a corresponding uptick in the use of phthalate alternatives, about which less is known. 

Our Grade: Fail (avoid if you can)

Keep PVC and Plasticizers Away from Your Family

There are still a lot of knowledge gaps regarding phthalates and phthalate alternatives and their effects on human health. What we know is concerning enough to avoid these nasty chemicals.

Other Harmful Chemicals in Crib Mattresses

Chemical Fire Retardants and Chemical Flame Barriers

Flame retardants are a significant problem across a range of consumer products, including anything made of flexible polyurethane foam (foam and memory foam mattresses, car seats, upholstered furniture) and electronics.

Flame retardants have nasty health effects, having been linked to a range of diseases and disorders, from hyperactivity to early puberty to cancer. 

And unfortunately, researchers have found chemical flame retardants in a range of products meant for babies and young children: car seats, baby carriers, changing table pads, infant crib mattresses, nursing pillows, strollers, toys….

Interestingly, not all polyurethane foam products contain fire retardants. Duke University’s Foam project analyzed 2215 samples of foam sent into the lab by members of the general public. They’re findings are illuminating:

  • In approximately 9% of samples (203 units), researchers detected two or more fire retardants.
  • In approximately 41.5% of samples (919 units), researchers detected only one of the fire retardants tested for.
  • In almost half of the samples (1093 units, representing roughly 49%), the researchers didn’t detect any of the flame retardants tested for.

Despite this, further research shows that fire retardants are so common in our lives and environment, they now show up in some very unwelcome places, from our supermarkets to our breast milk

Our Grade: Fail (avoid if you can)

Look for Products That Use Natural Flame Barriers

As parents, we personally advocate an “abundance of caution” approach. Given that natural and non-toxic flame barriers exist – coconut coir and wool are two examples – it makes sense to look for a crib mattress that doesn’t contain harmful chemical flame retardants. 

Volatile Organic Compounds

Furniture, building products, glues, paint, cleaners, air fresheners and other day-to-day products can all release volatile organic compounds (VOCs) into the air in our homes. 

Some VOCs fit into the other classes of chemicals discussed here. For example, the class of fire retardant known as polybrominated diphenyl ethers are VOCs, as are toluene diisocyanates, used in flexible polyurethane foam. 

VOCs are linked to cardiovascular disease, allergies, fatigue, asthma, reproductive disorders, kidney and liver damage, and cancer  – among other things (source). In other words, it’s worth taking them seriously and trying to reduce VOCs in our homes. Especially considering the fact that young children may be more susceptible to the ill effects of VOCs than healthy adults.

If you’ve heard about mattress off-gassing, you’ll be interested to know it relates to VOCs. Off gassing is the process by which VOCs are released from the chemicals inside your mattress into the air.

Our Grade: Fail (avoid if you can)

Buy Low VOC Products with Independent Emissions Tests

Greenguard Gold is the gold standard for ensuring a product has low VOC emissions. Only buy mattresses for your baby and family that meet this standard, and choose minimally processed crib mattress materials that are from plants (eg. cotton, coconut, natural latex) or animals (eg. wool) to reduce VOC exposure.

Formaldehyde

Formaldehyde is a VOC you’ve most likely heard of before. Being exposed to formaldehyde can cause skin, eye, nose and throat irritation, and may cause cancer at high levels. 

Unfortunately, we’re all pretty much constantly exposed to small amounts of formaldehyde, According to the USEPA:

The primary way you can be exposed to formaldehyde is by breathing air containing off-gassed formaldehyde. Everyone is exposed to small amounts of formaldehyde in the air that has off-gassed from products, including composite wood products.

At room temperature, formaldehyde is in gas form. Which means if you’re in a room with formaldehyde, there’s a good chance you’re breathing it in.  

You’ll find formaldehyde in composite wood products like hardwood plywood, particleboard and medium-density fiberboard, in building and insulation materials, in glues, paints, coatings, in some cosmetics and medicines, in dishwashing liquid and fabric softener, and in fertilizers and pesticides, for example.

Our Grade: Fail (avoid if you can)

Formaldehyde Belongs in the Lab, Not the Nursery

Look for crib mattresses that don’t use adhesives and glues, which may be a source of formaldehyde. You can also look for UL Environment’s Formaldehyde free verification.

Safe Non Toxic Crib Mattress Materials

Now that you know what NOT to buy, let’s turn our attention to some non-toxic crib mattress materials, and organic crib mattress materials, to look fo when shopping.

First, look for a crib mattress constructed from non-toxic materials. Generally speaking, non-toxic materials mean minimally processed materials from a plant or animal. However, when it comes to crib mattresses, innerspring coils are also a great choice, so long as they’re not used in combination with toxic crib mattress fillings and chemicals.

Additionally, look for materials that are also independently-certified as organic, where applicable. This means your little one won’t be sleeping on “natural” materials that happen to be treated with pesticides and other harmful chemicals during growing and processing.

Organic Cotton

Conventional cotton is environmentally and socially problematic. It’s a pesticide, land, and water intensive crop, and much of the world’s cotton likely relies on forced labor. Processing is also problematic, as the dyeing, bleaching and finishing processes involve various levels of hazardous chemicals. 

To be friendly to your baby and the planet, look for crib mattresses that use Global Organic Textile Standard (GOTS) certified organic cotton. This certification applies across the production and processing chain.

Our Grade: Pass

When Buying Cotton, Look for GOTS Certified Organic

Organic cotton means you can rest easy, just as your little one does! Safely grown and processed, organic cotton is a safe and non-toxic option for your little one’s crib mattress.

Coconut Coir

Coconut coir is a firm and somewhat spongy material made from the hairy outer shell of a coconut. You probably have coir (pronounced core) in your house already: hanging baskets are often lined with coir, as it makes for great potting, many doormats are made from coir, and some rope, as well.

The benefits of using coir in a crib mattress are many! 

  • It’s naturally moisture resistant and breathable, which also means it’s great at resisting mold. 
  • It’s firm, making it a natural choice for a baby crib mattress, which must be firm for safety reasons. 
  • It’s relatively hypoallergenic, and is good at keeping dust mites under control.
  • It’s a good temperature regulator, and will keep your baby cooler in summer than most foam mattresses.
  • Coir can be an “earth friendlier” crib mattress choice, since it helps to ensure the entire coconut is used.

A word of warning: when shopping for a crib mattress that uses coir, make sure the coir is bound with natural tree rubber latex, rather than synthetic latex. 

Our Grade: Pass

Coconut Coir is a Firm, Natural Alternative to Foam

Ideally, look for organic coconut coir, and ensure the coir mats aren’t covered in synthetic latex.

Natural Latex

Natural latex is a tree sap collected from rubber trees. Much like maple trees are tapped to collect maple syrup, so are rubber trees tapped to collect natural latex. 

When shopping for a crib mattress that contains natural latex, it’s wise to be aware of some misleading marketing terms, and take a second look at anything claiming to use 100% natural latex. 

100% natural latex – and terms like it – are common in crib mattress marketing. However, it can be confusing to figure out exactly what this means. 

In fact, no processed natural latex is “100% latex.” Additives used during production mean the finished latex product is between 90% and 97% latex (with the remaining percentage made up by additives). The Global Organic Latex Standard (GOLS) specifies certified products contain more than 95% certified organic raw material. 

However, you still want to look for these kinds of terms. Because they generally mean the latex used in the product is 100% natural, rather than a natural-synthetic latex blend, which is also common.

Our Grade: Pass

Natural Latex is a Sustainable and Safe Option

Natural latex is a firm, safe, and relatively eco-friendly choice, and a much better option than foam. If you’re concerned about latex allergies, be sure to talk to your paediatrician!

So How Do You Know What Really Matters When Buying a Crib Mattress?

As a parent who wants to do what’s best for their baby, I think it’s fair to question whether the regulations that currently exist are really protecting our kids … or serving corporate interests.

But it’s also important to understand what’s real and what’s fiction, so you can choose the best crib mattress for your baby.

It was this task of being a new parent – shopping for a crib mattress – that inspired me to start this website. Surely, someone could do a better job at explaining all the things to consider, and with actual scientific research to back it up – than what already existed on the internet.

And that’s what the articles on this page are all about. Helping you make the best decision for your family.

Our Crib Mattress Reviews

If you already have a basic idea of what you’re looking for, or already have a brand in mind, take a look at our crib mattress reviews to see what we think about some of the most popular crib mattresses on the market today,

Our philosophy is that we do the research, so you don’t have to.

Everything You Need to Know in One Place

If you’re just getting started trying to choose the right bed for your baby, you might find yourself overwhelmed by some of the terminology, size requirements, certifications and more. We’re slowly putting together a comprehensive guide – what we call “Crib Mattress University” – so you can find the info you need before you shop!

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