Children's Health

The More Moms Work, the More Kids Gain Weight?

Feb. 4, 2011 -- The more years a mother works during her children's growing-up years, the more likely the children's weight is to rise, according to a new study.

The findings echo some previous findings but also extend them, according to researcher Taryn Morrissey, PhD, assistant professor in public administration and policy at American University.

''Whereas many previous studies have examined intensity of maternal employment in terms of her work hours, we extend this line of work by showing an association between intensity of maternal employment over the child's lifetime -- that is, cumulative exposure to maternal employment as the child grows older -- and her child's BMI [body mass index]," Morrissey writes.

Bottom line: The longer a mom's employment -- whether she's toiling at a regular 9-to-5 job or works irregular hours -- the more likely her child is to gain more weight than is healthy.

"This is not a reason for moms to feel guilty," Morrissey tells WebMD. ''It’s not maternal employment per se that's the issue. It's an underlying environmental factor that leads to this association."

What that factor (or factors) is has yet to be uncovered, she says.

The study is published in the journal Child Development.

Working Mothers and Weight Gain in Kids

Morrissey and her team evaluated data on 990 children who were enrolled in the Study of Early Child Care and Youth Development, sponsored by the Eunice Kennedy Shriver National Institute of Child Health and Human Development. The children lived in 10 different cities across the country.

The researchers checked data about mothers' employment and kids' BMI when the children were in grades three, five, and six. The researchers looked at whether the mothers worked, whether they worked traditional schedules or not, and the length of the employment. They didn't look at how many hours were worked, Morrissey says, so there's no way to give a threshold of how many hours is linked to increasing weight in kids.

What they did find it that the total number of years that the mothers were working had a small but cumulative effect on the child's BMI.

How small? For every 5.3-month period the mother was employed, the child had a slight increase in BMI over and above what would be expected with normal weight gain with age.

"For a child of average height," Morrissey writes, "this is equivalent to a gain in weight of nearly 1 pound every five months above and beyond what would typically be gained as a child ages."

The association was strongest when the children were in fifth and six grade compared to third grade, perhaps because at that age children may make more food choices on their own.

Over time, the slight increases can tip the child into being overweight.