WSU study suggests smoking during pregnancy could lead to childhood obesity
Jun 30, 2025, 5:00 AM
A subject's waist is measured during an obesity prevention study in Chicago on Jan. 20, 2010. (File photo: M. Spencer Green, AP)
(File photo: M. Spencer Green, AP)
Can smoking during pregnancy influence a child’s risk of obesity later in life? A new study led by a Washington State University (WSU) researcher suggests it might.
More than 89% of children in the study showed a typical body mass index pattern—declining between ages 1 and 6, then gradually rising. But 11% had no early BMI dip. Instead, their weight increased rapidly starting around age 3.5.
“The most distinct finding is that we can identify children on a path to obesity as early as age 3.5 years,” Chang Liu, an assistant professor of psychology at WSU and the corresponding author of the new paper, said. “By age 9, children in this group reached an average BMI above the 99th percentile.”
Researchers found these children were more likely to have mothers who smoked during pregnancy or had a high pre-pregnancy BMI.
Smoking during pregnancy can have impact on child development
Previous studies have linked both factors to long-term effects on appetite, metabolism, and fat storage.
“While the study does not identify a causal explanation, there are indications from past research that prenatal smoking and maternal obesity can alter fetal metabolism and body fat development, potentially programming a child’s metabolic system in ways that persist after birth and may affect appetite, metabolism and fat storage throughout life,” the release said.
Liu led a team of scientists that included nearly 40 researchers from institutions across the country, including Harvard, The Pennsylvania State University, and the University of Washington, according to a press release from WSU.
Researchers used data collected between January 1997 and June 2024 from the national research program Environmental Influences on Child Health Outcomes (ECHO), the release said.
“For society, childhood obesity has enormous costs—both in terms of children’s immediate health and well-being, and the long-term healthcare burden as these children become adults with higher risks of diabetes, heart disease, and other chronic conditions,” Liu said. “If we can identify at-risk children by age 3.5 and intervene effectively, we could prevent a significant portion of childhood obesity and its lifelong consequences.”
Around one-fifth of American children are obese
About one-fifth of American children are obese, according to the release.
“We need more research to further understand these biological mechanisms and how they interact with genetic factors and postnatal environment to determine a child’s growth trajectory,” Liu said.
The study was published last month in JAMA Network Open.
Frank Lenzi is the News Director for KIRO Newsradio. Read more of his stories here.
