Pregnancy-related food cravings and excessive weight gain may stem from a newly identified biological shift in the brain’s reward circuits. According to a study published in Nature Neuroscience, researchers discovered that serotonin-producing neurons in the dorsal raphe nucleus become less active during pregnancy, which directly increases food-craving behavior in animal models.
Pregnancy Food Cravings Linked to Specific Brain Mechanism in New Study
The collaborative research project was led by Dr. Yanlin He of the Pennington Biomedical Research Center, alongside Dr. Pingwen Xu of the University of Illinois Chicago and Dr. Chunmei Wang of Baylor College of Medicine. Investigators set out to understand why highly palatable foods become so difficult for some expectant mothers to resist, tracking the exact cellular mechanisms that alter food motivation during gestation.
How SK3 Potassium Channels Alter Serotonin Neuron Activity
The reduction in serotonin neuron activity is driven by changes inside the brain cells themselves. Researchers found that the activity of the SK3 potassium ion channel increases in serotonin neurons during pregnancy. Because SK3 helps regulate whether neurons fire electrical signals, this heightened channel activity suppresses the firing rate of serotonin-producing neurons in the dorsal raphe nucleus.
To confirm this mechanism, the research team performed targeted tests. Removing the SK3 channel specifically from these serotonin neurons prevented the typical pregnancy-associated drop in neuronal activity and substantially reduced food-craving-like behavior in the study models. Conversely, artificially increasing SK3 activity in nonpregnant females successfully mirrored the neural changes and food-seeking behaviors observed during pregnancy.
Neural Pathways Linking Brain Regions to Food Motivation
Beyond identifying the role of the dorsal raphe nucleus, the team mapped the specific circuit connecting these serotonin neurons to the ventral tegmental area, a brain region governing reward and motivation. Activating this neural pathway reduced food-craving behavior in pregnant animals, while inhibiting the pathway triggered similar cravings in nonpregnant animals.
Dr. Yanlin He, Director of the Brain Glycemic and Metabolism Control Laboratory at Pennington Biomedical Research Center, noted that these findings improve our basic understanding of maternal nutrition and weight regulation. However, researchers caution that because the current findings rely on animal model studies, directly manipulating serotonin during pregnancy carries potential risks and requires extensive further study.
Future Directions and Clinical Translation
Translating these basic neuroscience findings into human clinical applications remains the ultimate goal for the research team. Investigators at Pennington Biomedical Research Center plan to gather additional evidence from human clinical studies to determine whether these findings can be translated to the prevention of maternal obesity.
Funding and institutional support for the published study were provided by the Pennington Biomedical Research Center, an innovative grant from the Department of Defense (W81XWH-20-1-0075), an American Diabetes Association postdoctoral fellowship award (1-17-PDF-138), and the U.S. Department of Agriculture’s Current Research Information System (58-3092-5-008).
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