Babies increase mothers’ brain sizes

[Guest guest]

Babies increase mothers’ brain sizes

By Iva Popa

Contributing Reporter

Wednesday, October 27, 2010

Being a mom is like going back to school: it increases brain size.

Research conducted at the Yale-New Haven Hospital and published this month has

found that in the six months after giving birth, parts of mothers’ brains that

are linked to motivation and behavior increase in size. The study, called “The

Plasticity of Human Maternal Brain: Longitudinal Changes in Brain Anatomy During

the Early Postpartum Period,†and conducted by National Institute of Mental

Health neuroscientist Pilyoung Kim, found there was a particular increase in the

grey matter area.

Researchers said the physical increase may have important functional benefits

for mothers with infants, but that the change may not be permanent.

Nineteen mothers — 10 who gave birth to boys and nine who gave birth to girls

— took part in the study, which was conducted in New Haven.

Pictures of the mothers’ brains were taken during two intervals: two to four

weeks after birth and then again when the infants were three to four months old,

Kim said. A comparison of both pictures showed that the volume of grey matter

— which is an area in the brain that plays a role in sensory and motor

function ­— increased significantly over that period of time.

“It would be interesting to see what the state of the brains was like at

baseline (before pregnancy) and also what happens to them months and years

later,†said Greer, associate professor and vice chairman of the

Department of Neurology at the School of Medicine.

Mayes, a co-author of the study and a professor at the Yale Child Study

Center, said the explanation behind these results lies in the physical and

hormonal changes a mother experiences in the first three to six months after

child birth. Mayes added that researchers have not yet ascertained whether

hormonal or environmental changes play a larger role in the increase of grey

matter.

Although the brains of all mothers in the study were impacted by the stresses of

having a child, and by learning how to cope with raising an infant, the changes

were not uniform, according to an American Psychology Association press release

about the study.

“In particular, the mothers who most enthusiastically rated their babies as

special, beautiful, ideal, perfect and so on were significantly more likely to

develop bigger mid-brains than the less awestruck mothers,†the press release

said.

A correlation between the gender of the child and increase in brain size could

possibly exist, Leckman said.

But Greer said the study does not provide enough data to say whether the gender

of the child plays a significant role.

Leckman added that he doubts any gender difference examined in future studies

would show a sizable effect on the size of the mother’s brain.

The number of children a woman has given birth to may also play a role.

About half of the women in the study were first-time mothers while the other

half had already given birth before.

“The birth of a child (especially the first child) is for most families a time

of hedonic transformation,†Leckman said, adding that this change might mean

that a woman’s first child has a greater impact on grey matter volume.

But when the researchers studied structural changes in the brain, they found

that both first-time and second- and third-time mothers exhibited similar

transformations, Kim said.

The study was published in the October issue of the scientific journal

Behavioral Neuorscience.