London, Feb 7 : Scientists have now confirmed what expecting mothers have long suspected - that pregnancy makes women more forgetful.
Australian scientists have found that a woman's memory may be impaired for at least a year after giving birth, although the effects are minor and mainly concern unfamiliar or demanding tasks.
For the current study, the researchers carried out a review of pregnancy studies conducted over the past 30 years.
These showed that pregnant women had "modest deficits" in memory, particularly when information was new or presented in a challenging way.
"The memory deficits many women experience during and after pregnancy are pretty much like the modest deficits you'd find when comparing healthy 20-year-olds with healthy 60-year-olds," the Scotsman quoted Dr Julie Henry, a psychology researcher at the University of New South Wales, as saying.
Dr Henry and co-investigator Professor Peter Rendell, of the Australian Catholic University, compared the memory performances of more than 1,000 pregnant women, mothers and healthy non-pregnant females involved in 14 studies around the world.
They found that pregnant women were considerably impaired on some, but not all, measures of memory.
The scientists found that women experienced most difficulty with memory tasks that relied on "executive cognitive control," i.e. those involving novelty or significant effort.
"Regular, well-practised memory tasks - such as remembering phone numbers of friends and family members - are unlikely to be affected," Prof Rendell said.
"It's a different story, though, when you have to remember new phone numbers or people's names, or hold in mind several pieces of information, such as when multi-tasking," he added.
The research is one of the first to confirm the suspicion from endless subjective reports that "baby brain" is a real phenomenon.
The results signify that the impairment is still evident a year after childbirth, but no studies have yet investigated beyond this period.
According to Dr Henry, scientists still did not understand why a woman's memory should be impaired at such an important time, but they suspected lifestyle factors played a role.
Other experts have suggested forgetfulness may stem from a feeling of being overwhelmed by the changes having a baby brings.
"In pregnancy your normal routines are disrupted and you can suffer sleep deprivation after the birth," Dr Henry said.
The study is published in the Journal of Clinical and Experimental Neuropsychology.