A recent study by the University of Royal Holloway London shows pregnant women display increased activity in the right side of their brain, which is the part that handles emotional skills.

Though the term "pregnancy brain" has long been disputed, the new study shows that something does in fact happen to a woman's brain capacity during pregnancy: they become more sensitive to emotive facial expressions.

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This effect later subsides when the woman's body normalizes after giving birth. The researchers' theory is that the increased sensitivity helps the mother-to-be become neurologically ready to bond with their child.

The research was formally presented at the British Psychological Society's annual conference on Wednesday by Dr. Victoria Bourne of the Department of Psychology at Royal Holloway.

For the tests, 39 pregnant women and new mothers were exposed to images of adult and infant faces with positive as well as negative facial expressions while their neuropsychological activity was being monitored.

So-called chimeric images were used, which combine one half of a neutral face and one half of an emotive face, to conclusively show which hemisphere of the brain is activated by the images.

The test showed that the activity of the right hemisphere of the brain of pregnant women was far higher than that of the new mothers when reacting to the images, especially when processing positive emotions.

Prior research may have touched upon the implicit psychological functions of these reactions, but this marks the first time the neurological process behind it has been studied.  Dr. Bourne says it may be a key step to understanding "a mother's bonding with her baby".

Meanwhile, "pregnancy brain" as a description of supposed memory lapses and cognitive problems with pregnant women has been disputed by Australian scientists in a study dating back to 2010, showing that when focused, pregnant women perform just as well as non-pregnant contemporaries in cognitive testing.

However, a competing study by the Bradford Institute for Health Research suggests that pregnancy hormones may very well temporarily affect spatial awareness, which account for the supposed forgetfulness of pregnant women.

The high levels of pregnancy-related hormones such as oestradiol, cortisol and progesterone significantly affect the hippocampus in charge of spatial memory, the study showed, and accounted for forgetting where you put your car keys or the route you take to get to work. These hormones also affect stress levels, sleeping patterns, mood and anxiety levels which can all contribute to the effect.

Dr. Louann Brizendine, director of the Women's Mood and Hormone Clinic of the University of California, emphasizes however that these hormone levels do not physically alter your brain in any permanent sense, but constitute instead more of a priority shift.

Women's health specialist Dr. Donnica Moore even speculated that the cognitive issues may even be an evolutionary benefit, helping women focus exclusively on the pregnancy and taking care of the child while forgetting other, less pressing issues.

TagsPregnancy, Pregnancy brain, Hormones, Forgetfulness, Study, University of Royal Holloway, British Psychological Society, University of California