Women who are obese before they become pregnant are at higher risk of having children with lower cognitive function than mothers with a healthy prepregnancy weight, new research suggests.
In their study, researchers from Ohio State University found that pre-pregnancy obesity was associated with a three-point drop in reading scores and a two-point reduction in math scores on a commonly used test of children’s cognitive function. The children were tested between the ages of 5 and 7.
Previous research has indicated that pre-pregnancy obesity can have a negative effect on fetal organs, such as the heart, liver and pancreas. This led the Ohio State researchers to try to find out whether a mother’s obesity also could affect the fetal brain.
“One way you measure the effects on the brain is by measuring cognition,” said Rika Tanda, lead author of the study and a doctoral candidate in nursing at Ohio State.
The research also supported findings in previous studies suggesting that several other conditions affect childhood cognition, including how stimulating the home environment is, family income, and a mother’s education and cognitive skills.
“The new piece here is we have a measure associated with the fetus’s environment to add to that set of potential risk factors,” said Pamela Salsberry, Ph.D., senior author of the study and a professor of nursing at Ohio State.
“If we have a good way to understand the risks each child is born with, we could tailor the post-birth environment in such a way that they could reach their maximum capabilities.”
The researchers used data from the National Longitudinal Survey of Youth (NLSY) 1979 Mother and Child Survey, a national sample of men and women who were 14-21 years old in December 1978. From that datas et, Tanda collected information on 3,412 children born to mothers who had been full-term births.
At the time of their interview, the children were between 5 and 7 years old and had no diagnosed physical or cognitive problems.
The researchers gauged the children’s cognitive function based on their performance on Peabody Individual Achievement Test reading recognition and math assessments.
The researchers calculated the mothers’ body mass index (BMI) based on their reported heights and weights. More than half of mothers had normal BMIs before pregnancy, and 9.6 percent were obese, meaning they had a BMI of 30 or higher.
While the score differences were small — just three points lower on reading and two points lower on math — they were important.
These effects of pre-pregnancy obesity were equivalent to a seven-year decrease in the mothers’ education and significantly lower family income, two other factors that negatively affect childhood cognitive function, according to the researchers.
Source: Ohio State University