During pregnancy, 94% of mothers’ gray matter undergoes changes

663,000 babies were born last year, or 2.2% less than in 2023, according to the latest report from the National Institute of Statistics and Economic Studies (INSEE). During pregnancy, women experience many effects, such as heartburn, nausea, abdominal bloating, etc. But being pregnant also has effects on the brain, as shown by a new study, published in the journal Nature Communications.

A study of pregnant women, and those who are not

As part of this work, researchers from the Autonomous University of Barcelona (UAB) have, for the first time according to a communiquéstudied the brains of pregnant women using neuroimaging techniques and on the female partners of pregnant women.

In detail, 127 women were experiencing their first pregnancy. They did MRIs five times: before conception, in the second and third trimesters, during the postpartum, and at one and six months after birth. This same examination was also carried out before they became pregnant.

At the same time, MRIs were also carried out on 20 female partners of pregnant women (to differentiate brain changes linked to biological effects from those caused by becoming a mother) and on 32 others, without children or plans to become pregnant or motherhood. . All 179 participants were asked to provide urine samples and questionnaires to assess mental health and, when mothers, maternal attachment to the infant.

94% of the total volume of gray matter impacted by pregnancy

Results :

– Gray matter volume in the brains of pregnant women was reduced by up to 4.9%, with partial recovery during the postpartum period.

– This reduction was observed in 94% of the total volume of gray matter and more particularly the areas linked to social cognition, that is to say the cognitive processes involved in social interactions.

Researchers show that these changes in the brain are linked to fluctuations in two estrogen hormones (estriol-3-sulfate and estrone-sulfate), which increase sharply during pregnancy and return to lower levels after delivery. They note that the greater the increase – and therefore decrease – in these hormones, the greater the final reduction in gray matter will ultimately be.

Finally, the study found that women who had better recovery of gray matter volume during the postpartum period were those who had a stronger bond with their baby 6 months after birth. This suggests that beyond biological processes, maternal well-being also plays a critical role in the evolution of gray matter.