Baby brain is the name given to the common belief that pregnancy and childbirth make women more forgetful and less focussed. They definitely do affect women’s brains, but could it be that they might actually be making them mentally sharper?
Firstly, the often quoted statistic about women’s brains shrinking by up to 7% during pregnancy is true. However by six months after the birth the brain will be back to normal size. But what of the other often quoted sign of baby brain, the inability to recall names or numbers?
Although 80% of pregnant women and new mothers report problems with their short term memory a lot of this might be down to cultural conditioning. Quite simply women might be noticing it because both they and those around them are expecting it to happen. On top of this new mothers also have the impact of the broken and poor quality sleep that comes with a new baby.
There will be some element of baby brain forgetfulness that is attributable to pregnancy. Rather than simply being a drop in mental ability this is actually a side effect of physical changes in the brain – changes that go on to have an impact for years afterward.
During the last trimester of pregnancy women become affected by stress as their “fight or flight” response is dampened down by the hypothalamus. There are sound evolutionary reasons for this – stressed mothers have less healthy babies, and in some cases the stress can affect the baby’s physical or mental development.
It’s not known how long these changes last after childbirth, but they have opened up an area of research around post-natal depression. About one in five new mothers will experience depression within three months of the birth. What has been linked to this are continuing high levels of corticotropin, the hormone that lowers the stress response in the last trimester of pregnancy.
Not only do women become less responsive to stress in the last trimester but they become bolder as well, and more prepared to handle confrontation. At the same time as this their ability to detect threat, fear, and even disgust in other people also increases. Again there are sound evolutionary reasons for this, as it makes the woman able to better defend or provide for herself and her child.
We’ve already seen that the shrinkage of the brain during pregnancy has been reversed by six months after the birth. However it isn’t simply that the brain returns to its original size. From three weeks after the birth the brain starts to change physically as well. The regions of the brain that deal with reasoning, the regulation of emotions, and empathy all start to grow to a greater size that before. Far from the stereotype of baby brain this is actually a physical change in the capacity of a new mother’s brain to better cope with the new challenges, new emotions, and changed relationships that motherhood brings.
Besides these physical changes the longer term effects on the brain are less clear. Whilst some studies suggest a link between increased pregnancy and Alzheimer’s in later life there are others that suggest that a link between increased breastfeeding and lower incidences of Alzheimer’s. One suggested reason for the suggested protection given by breastfeeding involves cell exchange between the mother and child, with new neurons being generated in the mother’s brain as a result.
Whatever the long term effects there is little doubt that pregnancy prompts huge changes in the mother’s brain – changes that are much more positive and fundamental than commonplace ideas about baby brain would suggest.
If you found this post about baby brain interesting why not sign up for my monthly newsletter here with three stories every month on the less travelled side of relationships and psychology.