Maternal obesity doubles the risk of developing autism in children

By Dr. Liji Thomas, MDReviewed by Benedette Cuffari, M.Sc.Sep 26 2024

New research reveals that maternal obesity before and during pregnancy significantly increases the risk of neuropsychiatric and behavioral conditions in children, including a 32% higher risk of ADHD and more than double the risk of autism.

Study: Associations between maternal preconception and pregnancy adiposity and neuropsychiatric and behavioral outcomes in the offspring: A systematic review and meta-analysis. Image Credit: Reshetnikov_art / Shutterstock.com

Does maternal fat mass carry long-term mental health risks for the offspring? A recent study published in Psychiatry Research investigates the potential relationship between maternal fat mass and long-term mental health issues in children born to these mothers.

How does obesity during pregnancy affect infant health?

As obesity rates throughout the world continue to rise, the presence of obesity both before and during pregnancy among women has become a significant public health issue. Maternal adiposity can increase the risk of adverse neonatal outcomes, including preterm birth, small or large for gestational-age infants, and stillbirth.

Recent evidence also suggests that obesity during pregnancy may increase the risk of neuropsychiatric and behavioral outcomes in childhood. As compared to children born from mothers with a healthy body weight before pregnancy, children born to overweight or obese women are at an increased risk of autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), mood disorders, schizophrenia, and various psycho-neurotic mood, stress, and somatization disorders.

Nevertheless, these studies have produced conflicting results due to differences in sample sizes and incomplete statistical control for risk factors.

About the study

The current study involved a systematic and comprehensive review of published research investigating the association between maternal adiposity and neuropsychiatric disorders in offspring.

A total of 42 studies were included in the meta-analysis, which comprised over 3.68 million mother-offspring dyads. The included studies assessed the risks of ADHD, ASD, mood disorders, anxiety disorders, externalizing disorders, and poor peer relationships. All outcome risks were separately calculated for preconception and pregnancy fat mass.

Effects of maternal adiposity

Being overweight during the preconception period or pregnancy increased the risk of ADHD in offspring by 18% and 19%, respectively, as compared to children born to non-overweight mothers. Obesity during the preconception stage or pregnancy increased the risk of ADHD in offspring by 57% and 32%, respectively, as compared to children born to normal-weight mothers.

ASD risk was increased by 9% and 42% with preconception overweight and obesity, respectively. During pregnancy, maternal obesity was associated with a two-fold increased risk of ASD in offspring. Conduct disorder, which is associated with severe antisocial and aggressive behaviors, was 16% more likely in the offspring of mothers with preconception obesity but not those who were overweight before becoming pregnant.

Psychosis, externalizing behaviors, and issues with peers were more likely by 61%, 30%, and 47%, respectively, with maternal preconception obesity but not overweight.  

Disorders of mood, anxiety, personality, eating, or sleep were not examined for their association with preconception or pregnancy maternal adiposity due to limited data. However, the current narrative review suggests a higher risk of anxiety and psychotic disorders in these children.

Potential explanations

The association between mental and behavioral abnormalities with maternal adiposity may be attributed to adiposity-related low-grade systemic inflammation, oxidative stress, perturbation of fatty acid metabolism, and hormonal imbalance.

Adiposity during preconception and pregnancy are independent risk factors for maternal mental illness, whether acute or chronic, which may confound these associations.

Adiposity is also associated with a higher prevalence of gestational diabetes and pregnancy hypertensive disorders, both of which are associated with an increased risk of neuropsychiatric and behavioral disorders in the offspring. Gestational diabetes and hypertensive disorders during pregnancy are positively associated with obesity in childhood, which is an independent risk factor for mental illness.

Conclusions

The study findings indicate that the offspring of mothers who have accumulated fat mass are at an increased risk for long-term neuropsychiatric and behavioral problems that is dose-dependent. There are both independent and combined risks of abnormal outcomes related to brain development in the offspring associated with maternal obesity and excessive weight gain both before and during pregnancy. 

To accurately assess the impact of adiposity on offspring, it is crucial to consider risk factors like maternal adiposity, diabetes, and altered levels of fatty acids like arachidonic acid, which are key to fetal brain development. Thus, future research is needed to target confounding factors in multiple sociodemographic, environmental, genetic, and biological domains.

Preconception weight management may mitigate such adverse effects in the offspring.”