Obese mothers who consume large amount of fat during pregnancy risk “rewiring” their developing child’s brain, putting them at greater risk of chronic complications later in life, a new study from Yale University has found.

The study, which is published in the journal Cell, shows that a high intake of fat during the third trimester corresponds to abnormal changes in the unborn baby’s neuronal circuits. Dr. Tamas Horvath, senior author and a professor at Yale University School of Medicine, said in an email to Medical Daily that these changes are appeared to be clustered around the hypothalamus, a key brain region associated with metabolism regulation. This results in a significant increase in the child’s risk of developing metabolic disorders such as obesity and type 2 diabetes.

“The fundamental message of this work is that the developing brain is highly vulnerable to maternal diet during a very specific period,” he said. “While we studied mice and identified that vulnerable period being lactation, in humans the same period of brain development occurs during the third trimester of pregnancy. Thus the implication for the public is the emphasis of proper diet of the mother during this critical period of pregnancy with far reaching implications for the health of the child later in life.”

Several previous research efforts have shown that children with obese mothers appear to “inherit” an elevated risk of excessive weight gain and metabolic complications. However, few studies have been able to explain the developmental specifics of this association. Horvath and colleagues shed new light on the matter by providing a more detailed map of the so-called metabolic programming that occurs during gestation.

In an experiment with mice, they found that mouse mothers who fed a high-fat diet during this crucial programming period had offspring with abnormalities in the hypothalamus region. As a result, these offspring had problems with glucose metabolism and remained overweight throughout their lives. In addition, they showed signs of altered insulin signaling in the brain.

Obesity during Pregnancy

The current study is the latest in growing series of efforts to illuminate the potential consequences of obesity during pregnancy. Another example is a University of Edinburgh study from last year, in which researchers show that children born to obese mothers die earlier and are more likely to develop cardiovascular disease. Researchers and health officials hope that these papers will eventually help rein in the overwhelming epidemic that currently affects more than one-third of U.S. adults.

Dr. Jens Bruning, a researcher at the Max Planck Institute for Neurological Research and co-author of the current study, said in a press release that the new findings may also help physicians improve prenatal care. By pinpointing a critical moment in the child’s metabolic programming, the results reveal a developmental stage where proper nutrition is more important than ever. "Given that gestational diabetes frequently manifests during the third trimester, our results point toward the necessity of more intensified screening of mothers for altered glucose metabolism, as well as tightly controlled antidiabetic therapy if any alterations are detected during this critical period," he said.

Source: Horvath T, Bruning J, Vogt et al. Neonatal insulin action impairs hypothalamic neurocircuit formation in response to maternal high fat feeding. Cell. 2014.