Study shows link between pre-pregnancy obesity and lower test scores

Women who are obese before they become pregnant are at higher risk of having children with lower cognitive function - as measured by math and reading tests taken between ages 5 to 7 years - than are mothers with a healthy prepregnancy weight, new research suggests.

In this large observational study, prepregnancy obesity was associated, on average, 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.

Previous research has suggested that a woman’s prepregnancy obesity can have a negative effect on fetal organs, such as the heart, liver and pancreas. Because fetal development is rapid and sensitive to a mother’s physiological characteristics, Ohio State University researchers sought 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.

Prepregnancy obesity: a complex risk factor for selected birth defects Obesity is associated with increased risk of many adverse health conditions. During pregnancy, obesity presents particularly important challenges for both mother and baby. Over the last 20 years, studies have emerged indicating an association between prepregnancy weight and risks of birth defects. However, few studies have examined the mechanisms through which this association occurs. Understanding the underlying mechanisms may provide clues to public health strategies for the prevention of birth defects associated with maternal obesity. This article briefly reviews existing literature on the association between maternal obesity and birth defects, discusses potential underlying mechanisms, and suggests research needed to improve our understanding of this important association.

"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, 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 research appears online and is scheduled for future print publication in the Maternal and Child Health Journal.

Prepregnancy Obesity as a Risk Factor for Structural Birth Defects Results Mothers of offspring with spina bifida, heart defects, anorectal atresia, hypospadias, limb reduction defects, diaphragmatic hernia, and omphalocele were significantly more likely to be obese than mothers of controls, with odds ratios ranging between 1.33 and 2.10. Mothers of offspring with gastroschisis were significantly less likely to be obese than mothers of controls.