Pregnant women are often embarrassed by their forgetfulness and loss of focus, but perhaps they need not be. A new study has found the "pregnancy brain" is real and it happens due to changes in the brain structure in expecting women.

The brain fog experienced during pregnancy is probably part of a bigger plan to bond the mother with the baby, the study, published in the journal Nature Communications, found.

The researchers found a strong association between increased levels of pregnancy hormones and changes to the neural architecture in specific areas of the brain.

Often known as "baby brain," "momnesia" or "mommy brain," the phenomenon is very common. However, measuring its effects has proved to be a scientific hurdle.

The lead author, Leiden University neuroscientist Elseline Hoekzema, has worked on this aspect in her previous studies.

In a 2016 study, Hoekzema found that there was a significant loss of gray matter during pregnancy.

"During pregnancy, a woman is exposed to an unparalleled flood of hormones," Hoekzema said in 2020. The researcher received a €1.5 million European Research Council grant for continuing research into this field that year.

"Animal studies have shown that these hormones trigger far-reaching changes in the maternal brain and behavior. In previous studies, we discovered that pregnancy renders long-lasting changes in human brain structure," Hoekzema further said, reported ScienceAlert.

In the latest study, Hoekzema and her colleagues used MRI scans to map the brains of 40 women. The scans were taken before pregnancy, and also before and after birth, including a year after the baby's delivery.

The scans were then compared to 40 women who were not pregnant at that time.

Additionally, urine samples were collected every two to four weeks from the pregnant group to assess hormone levels.

The study was further supported by surveys and questionnaires to analyze nesting behaviors, sleep patterns and levels of psychological distress.

The results, based on the 28 participants who completed the study, provided evidence that pregnancy changes the brain networking pattern. The change was most significant in the Default Mode Network, an area associated with contemplation and daydreaming, according to the outlet.

"These findings suggest that the neural changes of pregnancy may render a blueprint that facilitates the subsequent development of the mother-infant relationship, which could then potentially be further reinforced by the interaction with the infant," the authors wrote in the paper.

Admittedly, finding a clear link in these studies is difficult, making these findings speculative in nature. However, more studies with larger sample sizes and better analytical tools will help in understanding these changes at the cellular level.

One thing is for sure, pregnant women should be cut some slack the next time they zone out. After all, they have no control over it.