A new study shows that nearly a third of mothers report having trouble affording diapers for their children. The study out of Yale University also shows that close to one in ten moms leave kids in wet or dirty diapers to make their supply last longer. More than eight hundred pregnant and parenting women were surveyed. Thirty percent reported they experienced a time when they could not afford diapers. Doctors say children who are not frequently changed are more likely to have urinary tract infections and diaper rashes. Researchers say a mothers' stress related to diapers was right behind concerns about food and housing -- and made many moms feel ashamed.