Scientists originally thought that women experience 'baby brain' after childbirth, as a result of the huge life changes that come with having a child.
However, a new study has revealed that the condition may be caused by hormonal changes that take place during pregnancy.
Researchers from the Francis Crick Institute observed the behaviour and hormonal changes in female mice that were exposed to mice pups before, during and after pregnancy.
They found that the mice’s brains began preparing for "the big life change" of having offspring way before giving birth. Female sex hormones oestrogen and progesterone affect neurons in the medial preoptic area (MPOA), which is the part of the brain linked to parenting.
Scientists previously believed that mothers spent most of their time with their young because of hormones released after birth. But Jonny Kohl, group leader of the institute’s State-Dependent Neural Processing Laboratory, said: "What’s fascinating is that this switch doesn’t happen at birth - the brain is preparing much earlier for this big life change."
The research, published in the journal Science, also suggested that pregnancy can lead to a long-term rewiring of the female brain as some changes experienced during pregnancy become permanent.
Read more: 'Baby brain' in mothers caused by hormonal changes before birth, rather than after, scientists say (Sky News, 2-min read)
What is ‘baby brain’?
"Baby brain" or "pregnancy brain" is a condition during which women say they become forgetful or mentally "foggy" while pregnant and postpartum.
Scientists are not entirely sure why it happens, but hormonal changes combined with feeling more tired, morning sickness or insomnia can make focusing more difficult.
Dr Sarah Jenkins points towards a "ground-breaking" 2017 study carried out in Australia that sampled more than 700 pregnant women and 500 pregnant women. The study found that pregnancy does reduce cognitive function.
"Pregnant women couldn't concentrate for as long, attention spans decreased, focussing and ability to perform cognitive tasks, were found to be more difficult, than those who were not pregnant," she tells Yahoo UK.
"Another study done in 2017, showed there was a reduction in grey matter in the brain during pregnancy. This is really important for social cognition, which is why women have difficulty with brain fog, and processing what is going on what's going on around them, responding and communicating.
"It isn't like they don't know what is going on, but they may have more difficulty finding words and communicating as a result. This forgetfulness is what we associate with baby brain!"
Read more: Oti Mabuse discusses ‘painful’ health condition in pregnancy — What is Symphysis Pubis Dysfunction? (Yahoo Life UK, 3-min read)
What are the symptoms of ‘baby brain’?
Symptoms of this condition may vary, but forgetfulness is the most common complaint that patients have when experiencing it.
Other symptoms may include:
Feeling mentally “foggy” or slow
Feeling scatterbrained and unable to keep trains of thought
Misplacing items frequently
How long does ‘baby brain’ last?
Dr Veronika Matutyte reassures mums that the changes brought on by this condition "are usually mild and do not indicate any long-term cognitive decline". "They're just temporary blips on the radar of an otherwise standard pregnancy journey."
For some women, "baby brain" usually starts during the third trimester, while for others, it might linger for a few months after giving birth.
"The good news? Most women find that these symptoms gradually diminish, especially as they adapt to their new roles as mothers and get more rest," Dr Matutyte adds.
How do you cope with forgetfulness and feeling foggy?
Baby Centre has several tips on how to make your life a little bit easier if you feel the condition is affecting your everyday life. These include:
Put items you always need in the same place, particularly somewhere visible
When you make an appointment, add it to your calendar straight away
Make task lists and tick them off when they're done
"During this period, I would recommend a good diet high in fish oil to maintain brain function, daily vitamins, staying hydrated and generally looking after your health and stress levels," Dr Jenkins adds.
Dr Matutye adds that pregnant mums should get plenty of sleep and practice "mindfulness exercises like deep breathing or meditation to help stay centred".
"Remember, your body is doing something extraordinary; it's creating life. So, when those moments of forgetfulness occur, chuckle, take a deep breath, and know it's all part of the beautiful journey of motherhood."
Watch: What is 'baby brain' and is there science behind it?