Along with innerspring mattresses, foam mattresses are the second most common type of mattress. Foam mattresses are made from polyurethane, a lightweight material that is easier to handle and carry than the heavier innerspring mattresses. When you’re comparing mattresses, look for a measure of density. Higher density mattresses, with 1.5 pounds per cubic foot, are firmer and more substantial than lower density mattresses. A typical foam crib mattress will weigh between about 7 and 13 pounds and measure 3 to 6 inches thick. Because they are lighter weight, it may be easier to change crib sheets.
There are also memory foam mattresses available. This special kind of foam retains shapes and impressions, so if you push your hand into the foam, it will retain the handprint. The memory foam found in baby crib mattresses is typically firmer than the kind found in adult products like pillows and mattresses — it would be unsafe for a baby to sleep on a softer surface. Memory foam is heavier, with mattresses weighing as much as 20 pounds, and it is typically more expensive than traditional polyurethane foam.
Whether you’re looking at a traditional foam or a memory foam mattress, one simple test of quality you can use is the resiliency test. Resiliency is a measure of how fast a mattress “springs back” after weight is pressed on it. Try pushing down on the mattress with your hand in the store and seeing how fast it regains its shape. In general, you want a mattress with greater resiliency, meaning it springs back faster. This mattress will hold its shape longer than a less resilient mattress.