Excess Weight Among Pregnant Women May Interfere With Child’s Developing Brain

Summary: Maternal obesity may hinder their child’s brain development as soon as the second trimester of pregnancy. High maternal BMI is associated with changes to the child’s prefrontal cortex and anterior insula, two brain areas associated with decision making, and behavior.

Source: NYU Langone

Obesity in expectant mothers may hinder the development of the babies’ brains as early as the second trimester, a new study finds.

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.

In their new study, publishing online August 11 in the Journal of Child Psychology and Psychiatry, the investigators examined 197 groups of metabolically active nerve cells in the fetal brain. 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. They found only two areas of the brain where their connections to each other were statistically strongly linked to the mother’s BMI.

“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 Moriah Thomason, PhD, the Barakett Associate Professor in the Department of Child and Adolescent Psychiatry at NYU Langone Health.

As obesity rates continue to soar in the United States, it is more important than ever to understand how the condition may impact early brain development, says Thomason, who is also an associate professor in the Department of Population Health at NYU Langone.

Previous studies showing an association between obesity and brain development had mostly looked at cognitive function in children after birth. The new investigation is believed to be the first to measure changes in fetal brain activity in the womb, and as early as six months into pregnancy.

Thomason says this approach was designed to eliminate the potential influence of breast feeding 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.

For the investigation, the research team recruited 109 women with BMIs ranging from 25 to 47. (According to the National Institutes of Health, women are considered “overweight” if they have a BMI of 25 or higher and are “obese” if their BMI is 30 and higher.) The women were all between six and nine months’ pregnant.

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As obesity rates continue to soar in the United States, it is more important than ever to understand how the condition may impact early brain development. Image is in the public domain.

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. Then, they compared the study participants to identify differences in how groups of neurons communicate with each other based on BMI.

The investigators caution that their study was not designed to draw a direct line between the differences they found and ultimate cognitive or behavioral problems in children. The study only looked at fetal brain activity. But, Thomason says, they 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.

Funding: Funding for the study was provided by National Institutes of Health grants R01 MH110793, R34 DA050287, R01 MH122447, and R21 ES026022.

In addition to Thomason, other NYU researchers involved in the study included Carly Lenniger, BS. Megan Norr, BA, of the University of California Berkeley, served as the study lead author. Additional research support was provided by Jasmine Hect, BS, of Wayne State University in Detroit, Michigan, and Martijn van den Heuvel of VU University Medical Center in Amsterdam, the Netherlands.

About this neurodevelopment research article

Source:
NYU Langone
Contacts:
Shira Polan – NYU Langone
Image Source:
The image is in the public domain.

Original Research: Closed access
“An examination of maternal prenatal BMI and human fetal brain development” by Megan E. Norr Jasmine L. Hect Carly J. Lenniger Martijn Van den Heuvel Moriah E. Thomason. Journal of Child Psychology & Psychiatry.


Abstract

An examination of maternal prenatal BMI and human fetal brain development

Background
Prenatal development is a time when the brain is acutely vulnerable to insult and alteration by environmental factors (e.g., toxins, maternal health). One important risk factor is maternal obesity (Body Mass Index > 30). 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.

Methods
The present study examines this possibility at the level of macrocircuitry in the human fetal brain. Using a data‐driven strategy for parcellating the brain into subnetworks, we test whether MRI functional connectivity within or between fetal neural subnetworks varies with maternal prenatal BMI in 109 fetuses between the ages of 26 and 39weeks.

Results
We discovered that strength of connectivity between two subnetworks, left anterior insula/inferior frontal gyrus (aIN/IFG) and bilateral prefrontal cortex (PFC), varied with maternal BMI. At the level of individual aIN/IFG‐PFC connections, we observed both increased and decreased between‐network connectivity with a tendency for increased within‐hemisphere connectivity and reduced cross‐hemisphere connectivity in higher BMI pregnancies. Maternal BMI was not associated with global differences in network topography based on network‐based statistical analyses.

Conclusions
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.

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