Expectant mums need to stop blaming their bump for memory lapses, say experts who want to dispel the "baby brain" myth.
BBC News website readers have been sending in their comments on the story.
I've had 'baby brain' symptoms
I'm currently 25 weeks pregnant with my first child and can only say I disagree with these findings. I have had a good education and have a good job working in law. I would normally describe myself as above average intelligence, however I have discovered "baby brain" to be a real phenomenon, and this has surprised me.
Mrs Amanda Smith, Kent
I'm in my third trimester and have definitely noticed a lack of brain storage space! Whether it is just as a direct physical result of being pregnant, or being a full time primary school teacher combined with the physical and emotional changes of pregnancy. However, I think studies like this can actually be damaging. It is hard enough trying to get ready for motherhood whilst still feeling like you're doing your job properly! Dismissing the "baby brain" theory, can put even more pressure on mums-to-be.
Tricia Farley, Basingstoke
I have a two-and-a half-year-old and I was of the mind that baby brain was a fallacy. That was until I had my baby. I used to be an office manager; competent, organised and able to think quickly, but now I struggle. I don't feel that I could confidently go back to work doing the same role as effectively as I used to.
"Now I have to write everything down"
I have had four babies, and I am sure that my brain goes to pot while I am pregnant. Even if this is only due to tiredness, it is still a real effect. The way that people perform in tests is not the same as how they perform in their normal activities, when they are not concentrating as much.
Mrs M J Wood, Farnborough, Hants
I neither expected nor wanted to experience "baby brain" but it has had a fairly big impact on the way I retrieve information. I never used to have to bother with job lists, diaries, etc, whereas now I have to write down everything. I feel like pregnancy has taken a hammer to my brain and have still not recovered, even though my son is nearly six-months-old.
Cathy Rentzenbrink, London
One factor that could make a difference is tiredness. I've just come out of six months of four hours sleep a night, seven days a week, and it felt like my brains were dribbling out of my ears. Not a cognitive deficit but I really was having difficulty concentrating and thinking. Broken sleep also applies to new fathers as well, so someone should be seeing if they get "baby brain" as well.
'Baby Brain' hasn't affected me
I certainly didn't suffer from pregnancy brain and believed then that it was a myth. Some women I know have sworn by it though, personally I have always suspected it was an excuse to not do much work!
I am hoping to finish my PhD before I have the baby
Personally I don't feel pregnancy affected my brain. I am a mother of two children and I am expecting the third in May. During my second pregnancy I did many exams and passed all of them with relatively high scores, I was worried about the effect of stress on my baby though. In my third pregnancy, I passed my driving test for the first time and am hoping to finish my PhD before I have the baby.
Throwing money away on research such as this is ridiculous. I am a mother and even though my daughter is now two I regularly blame "baby brain" for my forgetfulness in jest. I believe that it is merely the distraction of preparing and caring for a child that causes one to forget other things. Having a child is a life changing experience - of course it's distracting.
I don't think that pregnancy itself addles the brain, but the symptoms of pregnancy do. I am six months pregnant with my third child and at times feel totally exhausted, stressed and tearful. These symptoms certainly don't help one's concentration and sometimes it can make you feel quite absent minded.
Samantha Earley, Mablethorpe, Lincs