Aug. 19 (UPI) -- People who are obese before and during pregnancy are more likely to have children who develop cognitive and behavioral difficulties as they age, a study published Thursday by JAMA Network Open found.
Children born to people who were obese, or severely overweight, late in pregnancy had lower IQ scores and performed less well on behavioral assessments during childhood and adolescence than those born to people at a healthy weight, the data showed.
Those who met the criteria for obesity based on body-mass index, a measure of weight coupled with height, also had higher rates of higher blood pressure during pregnancy, gestational diabetes and preterm births, the researchers said.
"We found that a mothers with higher weight in late pregnancy had children with poorer performance on tests of cognition and behavior in childhood and adolescence," study co-author Dr. Emily Oken told UPI in an email.
"This research suggests that maternal nutrition is important for child health over the long-term," said Oken, a professor of population medicine at Harvard University in Boston.
About 40% of adults in the United States are obese, according to the Centers for Disease Control and Prevention.
This includes more than half of all pregnant people, the agency estimates, and they are at increased risk for complications as a result, earlier research suggests.
For this study, Oken and her colleagues analyzed data on 11,000 pregnant people and their offspring.
They focused on weight in late pregnancy, which is a combination of a person's weight entering pregnancy and the weight gained during pregnancy, according to Oken.
Nearly 40% of the pregnant people in the analysis met the criteria for obesity during their third trimester, the researchers said.
Children in the study were assessed for intelligence at age 6.5 years using the Wechsler Abbreviated Scale of Intelligence test, according to the researchers.
They scored, on average, roughly 106 on the test in which scores of 130 and above are considered "superior" and 99 to 109 are "average," the data showed.
However, each 5-point increase in late pregnancy body-mass index, or obesity, was associated with a half-point drop in scores on the IQ test, the researchers said.
Higher late-pregnancy body mass index was associated with high scores on the 40-point Strengths and Difficulties Questionnaire, an assessment of behavior, according to the researchers.
"It is important for women to try to enter pregnancy in good health, including achieving a healthy weight if possible and also making sure they are screened for health conditions such as diabetes or high blood pressure," Oken said.
"It is very clear that prenatal health is important for long-term health of both the mother herself and for her child [and] the obesity epidemic has affected not only adults and older children, but also infants and young children," she said.