Summary: New research suggests that maternal obesity may begin to affect fetal brain development by the second trimester. Higher maternal BMI was associated with altered connectivity in the fetal prefrontal cortex and anterior insula—regions involved in decision-making and behavior.
Source: NYU Langone
Obesity in pregnant women may influence the developing baby’s brain as early as the second trimester, according to a recent study.
Researchers at NYU Grossman School of Medicine report a link between higher maternal body mass index (BMI) and changes in fetal brain connectivity, specifically involving the prefrontal cortex and the anterior insula. These brain regions are central to behavioral regulation and decision-making, and prior research has connected disruptions there to conditions such as attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorders, and disordered eating.
Published online August 11 in the Journal of Child Psychology and Psychiatry, the study examined functional MRI data from fetuses to explore how maternal BMI relates to the organization of neural networks before birth. Investigators analyzed 197 groups of metabolically active neural tissue and, using extensive computational methods, grouped them into 16 distinct subnetworks based on more than 19,000 potential interconnections. They identified two subnetworks—the left anterior insula/inferior frontal gyrus (aIN/IFG) and bilateral prefrontal cortex (PFC)—where connectivity strength showed a statistically significant association with maternal BMI.
“Our findings support the idea that maternal obesity may influence fetal brain development, which could help explain some of the cognitive and metabolic concerns observed in children born to mothers with higher BMI,” says Moriah Thomason, PhD, Barakett Associate Professor in the Department of Child and Adolescent Psychiatry at NYU Langone Health.
With obesity rates rising in the United States, understanding how maternal health affects early brain development has become increasingly important, Thomason adds. Most prior studies have assessed cognitive or behavioral outcomes after birth; this investigation is notable for measuring differences in fetal brain activity in utero, as early as six months into pregnancy, thereby reducing the influence of postnatal factors such as breastfeeding or early environment.
The research team enrolled 109 pregnant women whose BMIs ranged from 25 to 47. All participants were between 26 and 39 weeks’ gestation (approximately six to nine months pregnant). For context, the National Institutes of Health classifies BMI of 25 or higher as overweight and BMI of 30 or higher as obese.
Using fetal MRI, the team measured spontaneous brain activity and mapped patterns of communication between clusters of neurons across the developing brain. They then compared connectivity patterns across participants to identify associations with maternal BMI. The analysis found both increases and decreases in specific aIN/IFG–PFC connections: pregnancies with higher BMI tended to show stronger within-hemisphere connectivity and weaker cross-hemisphere connectivity in these networks.
The authors caution that the study was not designed to establish a direct causal link between the fetal brain connectivity differences they observed and later cognitive or behavioral conditions. The research measured brain activity before birth only. However, the team plans to follow the children longitudinally to determine whether these early connectivity patterns predict outcomes such as ADHD, behavioral dysregulation, or other long-term risks.
Funding: This research was supported by National Institutes of Health grants R01 MH110793, R34 DA050287, R01 MH122447, and R21 ES026022.
In addition to Moriah E. Thomason, NYU researchers on the study included Carly J. Lenniger, BS. Megan E. Norr, BA, of the University of California Berkeley served as the lead author. Jasmine L. Hect, BS, of Wayne State University and Martijn van den Heuvel of VU University Medical Center contributed additional support.
About this neurodevelopment research article
Source:
NYU Langone
Contacts:
Shira Polan – NYU Langone
Image Source:
The image is in the public domain.
Original Research:
“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, and Moriah E. Thomason. Journal of Child Psychology & Psychiatry. (Closed access)
Abstract
An examination of maternal prenatal BMI and human fetal brain development
Background
Prenatal development is a time when the brain is especially sensitive to environmental influences, including maternal health factors. Maternal obesity (BMI > 30) has been linked in previous work to elevated risks for a wide range of physical, cognitive, and mental health outcomes in offspring. It is plausible that higher maternal BMI affects brain organization before birth, establishing a pathway for later differences.
Methods
This study tested whether functional connectivity within and between fetal brain subnetworks varies with maternal prenatal BMI. Using a data-driven parcellation approach, the researchers defined subnetworks and analyzed MRI functional connectivity in a sample of 109 fetuses between 26 and 39 weeks gestation.
Results
Connectivity strength between two subnetworks—the left anterior insula/inferior frontal gyrus (aIN/IFG) and bilateral prefrontal cortex (PFC)—varied with maternal BMI. At the level of individual connections, both increased and decreased between-network connectivity were observed, with a trend toward greater within-hemisphere connectivity and reduced cross-hemisphere connectivity in pregnancies with higher maternal BMI. Global network topography did not differ by BMI based on network-based statistical tests.
Conclusions
Observed effects were localized to regions that later support behavioral regulation and integrative cognitive processes—areas previously implicated in obesity-related functional differences. By identifying neural differences before birth, this study supports the idea that maternal BMI-related risk may manifest in fetal brain organization, with potential implications for offspring cognitive development and mental health over the long term.