A new study suggests that the women's brains are permanently altered after giving birth and tend to have higher health risks compared to those who have no children.

Researchers at the University of British Columbia experimented on adult female rats by giving them hormone therapy. They wanted to determine whether motherhood affects the women's response to estrogen hormone treatments.

The experiment showed that the rats that received the estrogen therapy showed changes in their brains. During pregnancy, the brain shrinks by eight percent and returns to its original size six months after giving birth.

"We all know motherhood changes women's bodies, but it also changes their brains. Some changes are temporary, but others are permanent. Our research shows that, as a result of these transformations, mothers experience different cognitive abilities and health risks than women without children. They may even react to medication differently," Liisa Galea, study leader and a UBC neuroscientist, said in a university news release.

The results also explained why some mothers experience "baby brain" or forgetfulness during their last trimester up to six months after delivery. On a positive note, motherhood improves the memory and multi-tasking skills of the women which could the body's natural way to adapt to the need of keeping the family safe and organized.

The researchers linked the brain changes to the prolonged spike of hormones experienced by pregnant women. During pregnancy, the hormone level increases to up to 1,000 times higher than the typical level.

The findings of the study can be used in the development of new treatment and medical care for mothers, especially that they have higher risk of brain disorders.

"If you have given birth before, you have a better memory but experience an increased risk of developing Alzheimer's like conditions. But we don't know much about why this is the case," Galea told The Independent.

The study was presented in the 9th Annual Canadian Neuroscience Meeting.

In a case of scientific back-and-forth, a study in April disputed the idea that "baby brain" is a real issue for pregnant women. See: 'Pregnancy Brain' Deemed a Myth, According to New Study