But new figures show it's a serious problem for low income mothers.
28% or nearly 1 out of 3 poor moms say they have a hard time getting enough diapers, and some delay changing them to stretch their supply.
That can lead to serious skin rashes and infections, plus more stress on mothers.
Nearly a fifth of all children in the U.S. live at or below the government's poverty line. Although mothers can get federal help with food, and nutritional supplements, it doesn't include diaper assistance.
Diapers cost an average of $1000 a year. For women who make minimum wage, diapers would top 6% of her annuals earnings.
Childcare centers often require a certain number of diapers in order to admit a child. When mothers don't have those diapers, children may have to be taken out of daycare, potentially hurting the mother's ability to go to work, possibly putting her at risk of losing childcare subsidies.
Some communities try to fill the gap with diaper banks, but they aren't in every community, and there aren't enough to go around.
Teen mothers, who are much more likely to be poor, were not included in the survey, so the actual share of mothers with diaper problems could be much larger, say researchers.