Motherhood can supercharge the female brain, leading to lifelong improvements in mental skills and giving protection against the degenerative diseases of old age, researchers have found.

The findings challenge the popular belief that having a child harms mental acuity.

While there may be a decline in powers during pregnancy, this is more than offset by improving abilities after the baby is born. This, the researchers believe, equips women for the greater demands of life with a child.

“Pregnant women do undergo a phase of so-called baby brain, when they experience an apparent loss of function,” said Craig Kinsley, professor of neuroscience at the University of Richmond, Virginia.

“However, this is because their brains are being remodelled for motherhood to cope with the many new demands they will experience.

“The changes that kick in then could last for the rest of their lives, bolstering cognitive abilities and protecting them against degenerative diseases.”

Women often report problems with memory and reasoning after they become pregnant. A 2002 study by Angela Oatridge of Hammersmith hospital, London, reported that brain scans of pregnant women showed a 4% decline in size.

Last year, two Australian researchers reported that pregnant women consistently performed worse on tests for memory and verbal skills.

What Kinsley and his colleagues have found, however, is that these temporary declines are part of a process of remodelling the brain, most of which is eventually beneficial.

His studies, carried out on animals including rats and primates, show mothers become much braver, are up to five times faster at finding food and have better spatial awareness than those without offspring.

Kinsley will report his findings to the Society for Neuroscience’s annual meeting next month.

When he compared the brains of mother animals with those of nonmothers, he found physical changes related to these new-found skills.

In particular, nerve cells in crucial areas known to be linked to parenting had grown larger and developed more connections with neighbouring cells. This appeared to give the creatures more “computing” power. They also grew new sets of brain cells that Kinsley calls “maternal circuits”.

“Although most studies have so far focused on animals, it is likely women also gain long-lasting benefits from motherhood. Most mammals share similar maternal behaviours controlled by the same brain regions,” he said.

Another study found rats that had given birth were protected against degenerative diseases, with lower levels of a protein called APP, which in humans is linked with Alzheimer’s disease.

Such invasive research is impossible in humans, but Professor Alison Fleming carried out research at the University of Toronto showing that women’s senses become more acute after birth, enabling them to recognise instantly their own child’s odours and sounds.

The protective effects may also occur in humans. A study by Thomas Perls, associate professor at Boston University medical school, found that women who become pregnant after the age of 40 are four times more likely to live to 100.

Helen Burchell, 32, a graphic designer for a London branding agency, noticed a marked change in her cognitive skills during pregnancy.

“I definitely suffered from baby brain at first. Work was harder and simple tasks overwhelmed me,” she said. “Seven months into my pregnancy I had to accept that I couldn’t manage.”

However, since the birth of Martha, her first daughter, a year ago, Burchell found she lost the “baby brain” and her thought processes improved markedly. “There’s been a massive improvement. As a new mother you need a lot of organisational skills and you learn all the time,” she said.

“It shows that if anything employers should be seeking out women who have a family.”

The supermum phenomenon has also been seen in high-powered City jobs, epitomised by women such as Nicola Horlick, who combined having five children with managing investment funds worth £5 billion.

Helena Morrissey, 42, chief executive of an investment firm with £37 billion of assets, had her eighth child last year. She maintains that she finds it easier to juggle her responsibilities now than when she had her first child.

Explore Health

• Expert Advice

• Health Features

• Mental Health

• Alternative Medicine

• Child Health

• Health Club