Children of working mothers are significantly more likely to experience health problems -- including asthma and accidents -- than children of mothers who don’t work, according to new research from North Carolina State University.

But Dr. Melinda Morrill, research assistant professor of economics at NC State and author of the study, said these findings should not prompt a mass exodus of moms from the workforce.

“I don’t think anyone should make sweeping value judgments based on a mother’s decision to work or not work,” said Morrill. “But, it is important that we are aware of the costs and benefits associated with a mother’s decision to work.”

The study examined 20 years’ worth of data covering approximately 89,000 children from the CDC’s National Health Interview Survey collected between 1985 and 2004. The children studied were all school-aged and had at least one younger sibling.

Greater risk found

The researchers found when a mother works, it leads to a 200 percent increase in the child’s risk of having each of three different adverse health events: overnight hospitalizations, asthma episodes, and injuries or poisonings.

Previous studies have shown, on average, children have better health outcomes when the mother works. But those findings have been attributed to factors such as increased income for the family, availability of health insurance and an increase in the mother’s self-esteem.

However, Morrill found these positives didn’t have an impact on many kids’ physical health. She used advanced statistical techniques to focus specifically on the causal relationship between mothers working and children’s health.

Confounding factors

Her approach accounts for a number of confounding factors, such as how a child’s health affects the mother’s ability to work. For example, if a child is very sick, the mother may be more likely to stay at home.

“I wanted to look at mothers whose decision to work was not based on their children’s health,” Morrill says, explaining that a woman’s youngest child’s eligibility for kindergarten can influence her ability to return to the workforce.

In assessing health outcomes, Morrill looked solely at older children already enrolled in school, between the ages of seven and 17, whose youngest sibling was around kindergarten age.

This study is not the first to find negative outcomes to moms working outside the home. In January, a study revealed the more years mothers worked over their children’s lifetimes, the more their children’s body mass index (BMI) rose.

Morrill’s paper is forthcoming from the Journal of Health Economics.