It’s a wonderful thing to see – the deep bond between a mother and her baby.

And it may be because the mom’s brain shrank during pregnancy.

Yup, it got smaller.



A just-released study published in the journal Nature Neuroscience shows that pregnant women lose gray matter in areas of the brain that deal with people’s feelings and nonverbal signals.

However, the loss, rather than diminish this area of brain processing, appears to make it more efficient, enabling improved interpretation of their babies’ needs and emotions, and therefore increasing their maternal attachment.

Due to the time frame of the study, which was conducted by researchers in the Netherlands and Spain, it is not known whether the effects are permanent or temporary.

During the study, a group of fathers and first-time mothers had MRI scans before pregnancy and after giving birth. While the brains of the fathers remained unchanged, the study’s authors said, the scans of the mothers showed a loss of gray matter.

"Loss of volume does not necessarily translate to loss of function," Elseline Hoekzema, co-lead author of the study and a senior brain scientist at Leiden University in the Netherlands, told CNN. "Sometimes less is more."

She said that the loss of gray matter could "represent a fine-tuning of synapses into more efficient neural networks."

Another neuroscientist, Robert Froemke of New York University’s Langone Medical Center, compared the process to “spring cleaning.”