The study, which is published online July 29 and in the August print issue of the journal Pediatrics, found that one in 12 low-income moms stretches diaper supplies by leaving little ones in them after they've been soiled, a practice that can lead to skin and urinary tract infections.
"There are cases sometimes where moms are taking off a diaper, scooping out what's in it and putting it back on a child, we've heard about that," said study author Megan Smith, a Yale psychiatrist who directs the New Haven Mental Health Outreach for Mothers Partnership.
"Obviously, then, children are going to show more signs of irritation, discomfort, crying and then this in turn would make the mother feel less adequate about her parenting abilities, [and] impact her depressive symptoms and her stress levels," Smith said.
Beyond the immediate impacts on health and well-being, Smith says diaper need appears to have other important ripple effects, too.
"Mothers are required to bring a supply of diapers to a daycare center. If you can't bring a supply of diapers to your child care center your child is missing out on care, but also you're unable to attend school or work," she said.
For a woman who's working full-time at a minimum wage job, the cost of an adequate supply of diapers, which researchers estimate to be around $18 a week, or $936 per year per child, may eat up as much as 6 percent of her gross pay.
Government assistance programs like food stamps and the Women, Infants and Children program (WIC) help families afford some grocery and food items, but they don't cover diapers.
"We talk, as researchers, about the link between mental health and poverty, but oftentimes don't often operationalize what poverty looks like specific to mothers," Smith said, adding that diaper need is one of the most concrete and heartbreaking examples of the ways families suffer when money runs short.
For the study, Smith and her team surveyed nearly 900 low-income pregnant women and mothers in the New Haven area. Women were eligible for the study if they were over age 18 and could speak English or Spanish.
Along with questions about mental health, health care use and basic needs like food and housing, researchers asked, "If you have children in diapers, do you ever feel that you do not have enough diapers to change them as often as you would like?"
If they had trouble getting diapers, researchers asked whether they'd ever borrowed money from family or friends to afford diapers, gotten diapers from an agency, or stretched diapers by not changing them when they were dirty.
About 30 percent of women who had children in diapers reported that they didn't always have enough. Of those, 10 percent relied on donations of diapers or money from family and friends, 10 percent sought diapers from an agency or diaper bank, and 3 percent turned to other sources, like a church, for help.
Both age and race were significant predictors of diaper need. Grandmothers raising grandchildren were more likely than younger mothers to report trouble affording diapers. And Hispanic mothers were about twice as likely as black moms to admit they struggled with a short supply.
Smith says when many people hear about this problem, they wonder why low-income moms don't just switch to washable cloth diapers. For many, cloth diapers simply aren't a feasible solution.
"The problem is that most of the families we're talking about don't have washing machines in their homes. And when they do go to Laundromats, most facilities won't let you use their facilities for cloth diapers because their temperatures don't get high enough or they just don't want them," she explained.
Because diaper need appears to contribute to significant stress, Smith urged doctors to step up.
"Pediatricians should start asking families about this," she said, adding that there's a little-known network of nonprofit diaper banks around the country that may be able to help.
An expert who not involved in the research called the study "fascinating and eye-opening" and said the research should spur immediate public health action to provide relief.
"Governmental programs that offer assistance to pregnant women and children may need to readdress the methodologies currently in place in evaluating 'need' for poverty-stricken mothers in an attempt to prevent these adverse outcomes resulting from diaper need," said Dr. Kecia Gaither, director of the maternal and fetal medicine program at Brookdale University Hospital and Medical Center in Brooklyn, N.Y.
Gaither said she recommends that low-income women seek prenatal care early in their pregnancy. Just doing that, she said, usually gets vulnerable families connected to a social worker who can help solve practical issues, including insurance problems, and can connect them to community resources that may help them better meet a child's basic needs.
For more on diaper need, visit the The National Diaper Bank Network.