Nearly 85% of women become pregnant at least once in their lifetime, with approximately 140 million women becoming pregnant each year. Scientists have long known that pregnancy can cause certain changes in the brain, but how the nerves actually change has been unclear, to the extent that the saying 'one pregnancy is foolish for three years' has become widely circulated. But is that really the case? At the end of 2016, scientists analyzed imaging data before and after pregnancy and found that pregnancy can indeed make brain structures different, especially in areas related to the mind, where the volume actually decreased! This seems to support the claim of 'pregnancy foolishness'. But this study can only give people a partial understanding of the differences in the brain before and after pregnancy. No one knows what exactly happens to the brain structure and nerves throughout the entire pregnancy. Now, all of this may become clearer than ever before. A team including scientists from the University of California, Santa Barbara, recorded for the first time the brain changes during human pregnancy by conducting a brain scan on a mother, and published the results in the latest issue of Nature Neuroscience. In short, they found that there were both not so good changes and good changes. The less favorable change is that the human brain regions may shrink during pregnancy; But the benefit is that connectivity has become even better. This change covers the vast majority of brain regions, with only a small portion remaining unchanged during the transition to becoming a mother. The analysis subject selected by scientists is a 38 year old healthy female. In order to collect brain changes throughout their entire pregnancy, they conducted a total of 26 magnetic resonance imaging (MRI) scans and blood evaluations, with a cycle spanning the entire pregnancy: from 4 scans in the first 3 weeks of pregnancy, to 15 scans in 3 stages of pregnancy, and then to 7 scans 2 years postpartum, which can be described as unprecedented precision and comprehensiveness. For comparison, 8 control individuals who were not pregnant also underwent brain scans. After comparison, scientists found that the mother experienced a significant decrease in cortical volume and thickness, especially in areas related to social cognition, during the 9th week of pregnancy; At the same time, it was also found that there was an increase in white matter microstructure, ventricular volume, and cerebrospinal fluid. These changes should be related to the increase in levels of estradiol and progesterone. On the contrary, the integrity of a microstructure called white matter increases throughout the first 6 months of pregnancy. This part is located deep in the brain and is typically responsible for promoting communication between brain regions. Some of these changes, such as reduced cortical volume and thickness, still exist 2 years after the mother gives birth; Other changes return to prenatal levels around 2 months postpartum. Undoubtedly, scientists need to further study the longer-term effects of pregnancy on the brain, while also expanding the scale of their research subjects. However, people have finally gained a critical understanding of the neural changes throughout pregnancy. In the field of science, this is one of the most complete maps of neuroanatomical changes before, during, and after human pregnancy; In daily life, it will help clinical doctors and expectant mothers better cope with various changes in mental health, parenting behavior, and the brain. (New Society)