The AAP also cautions against being swayed by crib mattress manufacturers that claim their products can reduce the risk of sudden infant death syndrome (SIDS) as there’s no evidence that this is true. Instead, the AAP recommends using mattresses that meet the CPSC’s safety standards. There’s also no proof that so-called breathable mattresses have any sort of health impact, so beware of unregulated buzzwords. The CPSC recommends that a mattress used in a full-size crib be at least 27 1/4 inches by 51 1/4 inches, to prevent the possibility of head entrapment and suffocation between the mattress and crib sides, and the mattress should not be thicker than six inches. Shopping for crib mattresses may be important, but it is hardly the most scintillating thing parents want to do. So we did the work for you. Every product on Fatherly is independently selected by our editors, writers, and experts. If you click a link on our site and buy something, we may earn an affiliate commission.