There are many myths about cravings during pregnancy . That irrepressible desire to eat or drink something in particular can happen at any time, but it is enhanced during pregnancy. In fact, one in four pregnant women say they have had cravings at some point during their pregnancy.
But what is behind the cravings, what causes them? A study led by researchers from the August Pi i Sunyer Biomedical Research Institute (IDIBAPS) has identified the neural mechanisms responsible for cravings during pregnancy .
The results of the study, carried out on female mice and published in the journal Nature Metabolism , have shown that during pregnancy, the brain undergoes changes in the functional connections of the reward circuits, as well as the taste and sensorimotor centers.
Dopamine, responsible for cravings
Like pregnant women, female mice are more sensitive to sweets and develop compulsive eating behaviors of caloric foods.
“The alteration of these structures led us to explore the mesolimbic pathway, one of the signal transmission routes of dopaminergic neurons. Dopamine is a key neurotransmitter in behaviors of motivation or desire”, says Marc Claret, leader of the group of Neural control of metabolism at the August Pi i Sunyer Biomedical Research Institute (IDIBAPS).
The researchers observed that dopamine levels, as well as the activity of its D2R receptor, increased in the nucleus accumbens, a brain region involved in the reward circuitry .
“This finding suggests that pregnancy induces a complete reorganization of mesolimbic neuronal circuits , through DR2 neurons”, says Roberta Haddad-Tóvolli, a researcher on the team. “Likewise, these neuronal cells, and their alteration, would also be responsible for the appearance of cravings, since the anxiety for food, typical of pregnancy, disappeared after blocking their activity.”
During pregnancy, the brain undergoes changes in the functional connections of the reward circuits, as well as the taste and sensorimotor centers
Consequences of cravings in the baby
The researchers found that persistent cravings during pregnancy have consequences for offspring.
Specifically, they affect your metabolism and the development of neural circuits that regulate food intake, leading to weight gain, anxiety, and eating disorders .
“These results are surprising, since most studies focus on analyzing how the mother’s permanent habits, such as obesity, malnutrition or chronic stress, affect the baby’s health. However, our work indicates that it is enough with short, but recurring behaviors such as cravings , to increase the psychological and metabolic vulnerability of the offspring”, concludes Claret .
The conclusions could contribute to improving nutritional clinical guidelines for pregnant women, in order to ensure adequate prenatal nutrition and prevent the onset of diseases.
“Currently we do not know if these results observed in the mouse model can be extrapolated to humans. But, in any case, we would recommend moderating the episodes of cravings during pregnancy to minimize possible negative effects on the offspring”, concludes the expert.
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