New mum Deborah Quinn doesn't know if it's so-called "baby brain" she suffers from, but since her daughter was born, her memory hasn't quite been the same.

Since Olivia was born seven weeks ago, Quinn says she can't form thoughts as well as she used to and is forgetful.

"I put that down to a lack of sleep though," she says.

But even while she was pregnant, her brain wasn't quite as sharp as it used to be, the new-mum says.

"I probably couldn't recall as easily, and I was getting more sleep then."

These comments mirror what a lot of women say they experience - but research from Miami's Carlos Albizu University suggests having a child could in fact improve a person's memory.

In a series of experiments, new mothers scored better on tests of visuospatial memory - the ability to perceive and remember information about their surroundings - compared with women who didn't have children, the Daily Mail reported.

Researcher Melissa Santiago said the findings countered the belief that women experienced a decline in memory and cognitive function after they've had children.

"You don't have to feel that because you have kids, your memory isn't the same," Santiago told a meeting of the American Psychological Association.

In one of the tests, the women were asked to remember six symbols they had been shown and draw them. This was repeated several times.

The mothers were able to more accurately draw the symbols in the later tests than those without children.

During pregnancy mothers' brains can shrink up to five per cent, previous research has found.

But it returns to its normal size six months after childbirth, and during this time of re-growth, the brain may re-map itself in a way that was responsible for the memory changes seen in the study, Santiago said.

Midwifery adviser Norma Campbell from the NZ College of Midwifery said many new parents are sleep deprived, which could result in being forgetful and a bit muddled.

"You're also changing your priorities because you have a new baby and so things that were important before don't hold the same importance.

"How that's been couched is by labelling it 'baby brain'," she said.

Campbell said it's completely reasonable that a person who was known to be highly organised can change once they have a baby.

"Labelling it and dismissing it is not fair, I think we should be more supportive of new families."

The study looked at 35 first-time mothers and 35 childless women - mostly Hispanic.

Santiago admitted the findings would need to be verified by testing a larger sample of women of different ethnicities over a longer period of time.

- APNZ