According to global statistics, there are 140 million new pregnancies each year, and approximately 85% of women will have had at least one pregnancy at some point in her life. Although the physiological changes involved in the process are known at an increasingly detailed level, neurological changes that occur in the brain of the expectant mother were until now largely unknown.
To better understand this transformation, a team of researchers from the University of California, Santa Barbara, led by Laura Pritschet, followed a 38-year-old volunteer throughout the pregnancy, childbirth and the first years of the newborn’s life. They were carried out 26 MRI throughout the period covering the three weeks of preconception, the three trimesters of pregnancy and up to two years later to give birth.
The results, compared to those of eight other people who served as a control group, showed that the majority of regions of the cerebral cortex they decrease in thickness and lose volume during pregnancy, according to the article published in Natural neuroscience. However, neural connections became denser and more efficient from the ninth week of pregnancy, especially in areas associated with aspects socio-cognitive. Some areas of the brain, finally, were not altered at any time.
Areas that have undergone the most changes (dark) and those that have undergone the least changes (light).
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In addition to the generalized shrinkage of cortical volume and thickness, the researchers observed further development of the microstructure of the cortex. white matterof the ventricular volume and of cerebrospinal fluid. These changes were associated with fluctuating hormone levels, particularly progesterone and estradiol. Some of these changes, such as the shrinking of the cerebral cortex, were significant enough to persist after delivery and even two years later. Others, on the contrary, had already completely reversed two months after delivery.
“This study demonstrates that precision imaging studies can detect the full dynamic range of brain changes that develop during pregnancy with unprecedented temporal resolution,” he said in statements to Science Media Center Magdalena Martinez-Garcíapostdoctoral researcher in the Department of Psychological and Brain Sciences at the University of California. “The findings align with those previously revealed by larger longitudinal cohort studies of first-time mothers, suggesting that they may be an omnipresent phenomenon“.
The methods, he explains on his side Susana Carmona Cañabateprincipal investigator of the Neuromaternal Group of the Gregorio Marañón Health Research Institute, are “solid” and “innovative.” According to the specialist, “they use a methodology (dense sampling) which allows to have a very good temporal resolution” to trace “phenomena that vary greatly over time.” In addition, “it brings together data for the first time before, during and after pregnancy and measures not only cortical thickness, but also data on cortical integrity. white matter and hippocampus“.
The researchers propose that these neurological changes could be involved in some processes of perinatal mental healthin behaviors during education and in brain aging. “The way forward is now to evaluate this phenomenon on a larger number of subjects to assess the effect of very variable factors: type of delivery, breastfeeding, symptoms of depression, socioeconomic status, maternity leave, etc.,” Carmona emphasizes.
For example, the preeclampsia -high blood pressure and liver or kidney damage- were previously associated with neurological disorders. “Without a doubt, this study and others focused on the characterization of brain changes in pregnant women can help us understand, predict and prevent postpartum mental pathology, among other phenomena. But we are still far from formulating specific recommendations,” concludes the specialist.
