Baby mattresses: Foam vs. innerspring

When you're crib shopping, you'll also need to choose a mattress, which is typically sold separately. There are two general types of crib mattresses: foam and innerspring. Either is acceptable. Both types--if they're good quality--will keep their shape well and offer excellent support for infants and toddlers. There are differences, though. For one, foam--made from polyurethane--tends to be lighter. The densest foam mattress usually weighs 7 to 8 pounds, compared with 15 to 23 pounds for an innerspring mattress. So, although you're probably just lifting one corner at a time, changing your baby's sheets may be easier with a foam unit. Foam is also less springy and therefore less apt to encourage your child to use the mattress as a trampoline. Still, innerspring mattresses remain the most popular choice because it's the type of mattress most adults sleep on in the U.S.

Prices for foam and innerspring mattresses are comparable, ranging from $50 to $530, but spending between $90 and $200 should buy you a safe, serviceable mattress. Crib mattresses, whether foam or innerspring, must be firm and fit tightly in the crib. Check the fit before you buy by pairing any prospective mattress with the crib you choose. By law, all full-size crib mattresses must be at least 27 1/4 inches by 51 5/8 inches and no more than six inches thick. Still, mistakes happen. About 1,000 oval-shaped cribs with foam mattresses, for example, were recalled in August 2007 because the mattresses weren't properly sized, creating a gap, which posed an entrapment hazard to young children. (For the latest product recall information, visit www.recalls.gov.) A test: If you can squeeze more than two fingers between the mattress and the crib, the mattress is too small. Also, press on the mattress in the center and at the edges. It should snap back readily and should not confirm  to the shape of your hand. Think firm, as in brick-like. What seems too hard to you isn't too firm for a baby.

See our reports on crib mattresses, cribs, and crib alternatives for more information.