More decisive and 'multitasking': this is how the second pregnancy affects women's brains

The effect of hormones on brain function is a controversial topic because it lends itself to abuse by those seeking scientific confirmation of their biases. We have often heard that women's brains are not as good as men's in processes requiring mathematical skills, for example. Sexist statements of this kind are easy oversimplifications of an extremely complex and interesting phenomenon, which slow down research in this field. Because what is evident is that all the body's tissues are subject to the strong biological influence of these powerful molecules called hormones. If there are significant differences in the physiology of the liver, heart, or immune system between men and women, to cite a few well-studied examples, it would be very strange if the brain were the only organ that escaped their influence. A few years ago, a study was conducted that demonstrated that in humans, the male brain cannot be macroscopically distinguished from the female brain. It stirred up quite a controversy because it seemed to disprove the importance of hormones. The thing is, functional differences aren't necessarily visible to the naked eye.

For example, an article published a few weeks ago in the journal CommunicationBiology A study by scientists at the universities of Pittsburgh and Massachusetts demonstrated that the brains of male and female mice respond differently to opiates: in males, a protein called c-Fos is activated more intensely in areas related to addiction. This could help explain certain behavioral patterns related to recreational drug abuse and suggests that this problem should not be treated the same in men and women. Given this biochemical sensitivity of the brain to hormones, it is logical to think that the time when the female brain is most affected must be during pregnancy, when the levels of the main sex hormones change drastically in one direction or another in a matter of months. Indeed, it has long been known that the first pregnancy causes changes not only in the functioning but also in the structure of the female brain, especially in the areas related to establishing social bonds. Although less dramatically, the brains of parents also evolve toward more empathetic, less aggressive, and more protective behavior, precisely because of the corresponding hormonal changes (especially less testosterone, more prolactin and oxytocin).

Also in the second pregnancy

A new work recently published in the journal Nature Communications, Led by neuroscientist Elseline Hoekzema of Amsterdam University Medical Center, the study presents brain imaging data from over one hundred women across multiple pregnancies (including first-time mothers, women with a second pregnancy, and women without children), concluding that hormones continue to produce changes in the brain. In this case, the affected areas are those related to attention and sensory response, which are most involved in what we call multitaskingWhile the changes seen in the first pregnancy are repeated here, they are less intense. Researchers define these brain "improvements" as a computer software update that is irreversible.

The article concludes that these different changes are consistent with the challenges of multiple motherhood. While with a single child the most important thing may be establishing an emotional bond that ensures good care, when a second child arrives, the most urgent problem becomes how to care for both without going crazy. It's worth remembering that, as with most primates, human males were originally not very involved in child-rearing and that centuries of cultural evolution, which in some cases may still be ongoing, have been necessary for them to also contribute. In the absence of this involvement, it's logical that evolution would have prioritized providing mothers with the necessary resources to better cope with the demands of multiple offspring.

One of the main shortcomings of medicine is that, traditionally, the approach has been from a male perspective. Both in basic research and clinical practice, the many physiological differences between the sexes have been overlooked, either out of convenience or ignorance. This means that many of the treatments currently available were not designed for women's bodies. Although things have been changing for some years now, there is still much work to be done, as demonstrated by recent discoveries such as the one discussed here, which highlight the great plasticity of the brain, especially the female brain, and how little we know about something as common as pregnancy. In this context, studying the response of organs to hormones is necessary to ensure that both sexes receive the most appropriate healthcare support.