A good mattress not only makes bedtime cozier for your baby, it also supports his growing bones and keeps him safe while sleeping. Be sure to choose a firm crib mattress made specifically for babies, because a soft sleeping surface can be a suffocation hazard and raise the risk of SIDS. Mattresses designed for older children and adults may not be firm enough.
Other than that, what makes a mattress good is mostly a matter of preference. Consider cost, comfort, and durability, as your child will probably sleep in his crib for up to three years.
Types of crib mattresses
There are two basic types of crib mattresses: foam and innerspring.
Foam mattresses are generally the least expensive and the lightest option. These are available in a variety of thicknesses, usually between 3 and 6 inches. More important than thickness, though, is density. The better foam mattresses are high density, about 1.5 pounds per cubic foot. Unfortunately, most foam mattresses don't list density on the packing, so it's hard to know exactly what you're getting.
When in doubt, weight can be a good indicator; a heavier foam mattress is denser than one that's the same size but lighter.
A typical foam mattress weighs about 7 to 8 pounds, though mattresses made of memory foam (an especially dense form of polyurethane) can weigh close to 20 pounds. Keep in mind that you'll be hoisting up a side of the mattress, or lifting the whole thing out of the crib, when changing your baby's crib sheet. So don't pick a mattress that's too cumbersome!
Test how resilient a foam mattress is before buying. That is, when you push your hand down into the middle of the mattress and then remove it, how quickly does it regain its shape? A faster recovery rate is better. Sleeping babies make an impression on the foam, and it can be difficult for them to change position if the mattress retains their shape.
Innerspring mattresses are usually more expensive and can be more durable than foam. Manufacturers often equate the number of coils in an innerspring mattress with firmness, but factors such as the gauge of the wire and the number of turns per coil are just as important. Lower gauge means thicker wire, which is stronger and therefore firmer. Look for a mattress with 135 or more coils and a gauge of 15.5 or lower.
What about organic? A growing number of parents are choosing crib mattresses made of all-natural or organic materials, usually cotton or wool. These come in either foam or innerspring options.
Organic crib mattresses can be expensive, but some people say the peace of mind is worth the price. They contend that chemicals and industrial compounds used in standard mattresses – flame retardants known as PBDEs (polybrominated diphenyl ethers), vinyl, and polyurethane foam, for instance – emit toxic gases, and that the substances used to make mattresses could harm babies. Others say materials like latex can produce an allergic reaction in infants.
While researchers analyze issues of toxicity, advocates for going organic point out that if these chemicals could be harmful, the safest thing to do is to buy a crib mattress that doesn't use them.
A manufacturer's claim that a product is organic can mean a variety of things, but you can look for an Oeko-Tex Standard 100 certification (a globally uniform certification), which assures you that certain PBDEs and heavy metals were not used to make the mattress.
Important safety notes
Use caution with used or secondhand crib mattresses. Some studies link used mattresses to an increased risk of SIDS, but researchers aren't sure whether the used mattresses caused the increase in risk or were simply correlated with an increased risk.
The worry is that bacteria from a baby's bodily fluids can become lodged within a mattress. When the next baby starts sleeping on it, he would be exposed to bacteria that has been linked to an increased risk for SIDS, according to a study published in the British Medical Journal.
Though researchers found an association between used mattresses and SIDS, they stopped short of concluding that hand-me-down mattresses were a direct cause.
Still, others worry that improperly stored mattresses can become a haven for fungus, which may also pose a health risk to the next user. The bottom line: Unless you know that a secondhand mattress has been used and stored in a clean environment, and protected with a removable cover, buy a new one.
As for air mattresses, skip them – they're not safe for babies because the soft, giving surface is a suffocation hazard. The Consumer Product Safety Commission warns, "Never place infants to sleep on air mattresses or other soft surfaces (such as water beds and adult beds), which are not specifically designed or safe for infant use."
What to look for when buying
Is it the right size? The mattress needs to fit snugly in the crib, with no more than two fingers of space between the side of the mattress and the crib frame. If there's more space than that, the mattress is too small and could be a suffocation and entrapment hazard. By law, full-size crib mattresses must be at least 27 1/4 inches by 51 5/8 inches and no more than 6 inches thick.
Is it firm? Firm is good because too soft a surface can conform to a baby's shape and create a suffocation and SIDS hazard. The firmer the better. Even if it feels stiff to you, your baby will adjust to it. Consumer Reports suggests this test: "Press on the mattress in the center and at the edges. It should snap back readily and should not conform to the shape of your hand."
Is the ticking (mattress cover) sturdy? For water resistance, look for double- or triple-laminated ticking reinforced with nylon. This composition is also more resistant to tears, holes, and soggy diapers. Organic mattresses usually have cotton covers.
Is there enough venting? Look for small vent holes on the sides of the mattress that let air flow in and out. A mattress will smell better if it has plenty of vent holes to let odors escape. Diapers do leak, so this is important.
Is it certified? Crib mattresses must meet safety standards defined by the CPSC and the American Society for Testing and Materials. Organic mattresses are certified as organic using the Global Organic Textile Standard. In the United States, the largest certifier is Oregon Tilth, a nonprofit promoting sustainable agricultural processes.
What it's going to cost you
Thinner foam mattresses start at about $50, and denser models can cost as much as $100. Innerspring mattresses range from $100 to more than $250. Organic mattresses start at about $150 and can reach more than $500.
