Obesity in pregnant women may hamper the development of a baby’s brain, reveals study
Obesity is on the rise in the US and worldwide and it is associated with numerous negative health outcomes. A research team has now found that excess weight among pregnant women may interfere with a child’s developing brain. Obesity in expectant mothers may hinder the development of the babies’ brains as early as the second trimester, according to the authors.
Led by researchers at NYU Grossman School of Medicine, the investigation linked high body mass index (BMI), an indicator of obesity, to changes in two brain areas, the prefrontal cortex and anterior insula. These regions play a key role in decision-making and behavior, with disruptions having previously been linked to attention-deficit/hyperactivity disorder (ADHD), autism, and overeating. “Past studies demonstrate reduced executive functioning, memory problems, and differences in reward response and motivation in children born to high BMI mothers. Here, we report that maternal BMI relates to the development of the child’s brain networks in the womb,” Dr Moriah Thomason, the Barakett Associate Professor in the Department of Child and Adolescent Psychiatry at NYU Langone Health, told MEA WorldWide (MEAWW).
“Our findings affirm that a mother's obesity may play a role in fetal brain development, which might explain some of the cognitive and metabolic health concerns seen in children born to mothers with higher BMI,” says Thomason, who is also an associate professor in the Department of Population Health at NYU Langone.
Funded by the National Institutes of Health (NIH), the team also includes researchers from the University of California Berkeley, Wayne State University and New York University Medical Center, among others.
Previous studies showing an association between obesity and brain development have mostly looked at cognitive function in children after birth. “Prenatal development is a time when the brain is acutely vulnerable to insult and alteration by environmental factors (for example, toxins, maternal health). One important risk factor is maternal obesity. Recent research indicates that high maternal BMI during pregnancy is associated with increased risk for numerous physical health, cognitive, and mental health problems in offspring across the lifespan. It is possible that heightened maternal prenatal BMI influences the developing brain even before birth,” the findings state. Accordingly, the new investigation measured changes in fetal brain activity in the womb, and as early as six months into pregnancy. This approach was designed to eliminate the potential influence of breastfeeding and other environmental factors occurring after birth and to examine the earliest origins of negative effects of maternal BMI on the developing child’s brain, explains Thomason.
Obesity has nearly tripled since 1975 globally, says the World Health Organization (WHO). In 2016, more than 1.9 billion adults, 18 years and older, were overweight. Of these over 650 million were obese.
According to the WHO and the NIH, people are considered overweight if they have a BMI of 25 or higher and obese if their BMI is 30 and higher. For the current analysis, researchers recruited 109 women with BMIs ranging from 25 to 47. The women were all between six and nine months pregnant. The research team used MRI imaging to measure fetal brain activity and map patterns of communication between large numbers of brain cells clustered together in different regions of the brain. They examined 197 groups of metabolically active nerve cells in the fetal brain.
The investigators next compared the study participants to identify differences in how groups of neurons communicate with each other based on BMI. Using millions of computations, the study authors divided the groups into 16 meaningful subgroups based on over 19,000 possible connections between the groups of neurons. The team found only two areas of the brain where their connections to each other were statistically strongly linked to the mother’s BMI. “Overall effects were localized in regions that will later support behavioral regulation and integrative processes, regions commonly associated with obesity-related deficits. By establishing onset in neural differences prior to birth, this study supports a model in which maternal BMI-related risk is associated with fetal connectome-level brain organization with implications for offspring long-term cognitive development and mental health,” says the study published in the Journal of Child Psychology & Psychiatry.
Thomason emphasizes that as obesity rates continue to soar in the US, it is more important than ever to understand how the condition may impact early brain development. “This is evidence that the health status of a mother relates to rapidly developing connections in her fetus’ brain. This can be helpful for substantiating knowledge that we share with expectant mothers about the importance of healthy habits. This can also help understand what may be changing in the brain (here, prefrontal, insula connections) that underlies the association between maternal prenatal obesity and negative child outcomes reported in prior studies,” Thomason told MEAWW.
The authors caution that their study was not designed to draw a direct line between the differences they found and the ultimate cognitive or behavioral problems in children. The study only looked at fetal brain activity. However, the investigators now plan to follow the participants’ children over time to determine whether the brain activity changes lead to ADHD, behavioral issues, and other health risks.