Pregnancy health centre

Pregnancy affects spatial awareness

18th March 2010 - Researchers think they know why pregnant women sometimes forget where things are: it’s hormones affecting how the brain sees the world around us.
The study by the Bradford Institute for Health Research, University of Bradford, found that spatial recognition memory ability was reduced during the later stages of pregnancy. The effect also lasts for at least three months after the birth.

Mental map of our surroundings

To remember our way to somewhere, or where we put something, we have to be able to record a memory for a location, orientate ourselves with the surroundings - and importantly remember all this information later on.

This spatial memory is linked to a part of the brain called the hippocampus. This can be affected by changes in hormones.

Many expectant mothers report memory problems, but scientists still don’t know enough about this area.

Preg head

Only last month, Australian researchers said pregnancy wasn’t to blame for memory lapses. Growing babies can’t be blamed for what’s been called ‘Preg-head’, ‘ baby brain’ or ‘mumnesia’, they wrote.

At the time, Cathy Warwick, general secretary of the Royal College of Midwives, told us “The physical and emotional stresses on a woman’s body from pregnancy can make women feel more tired than usual. As we all know tiredness - for men as well as women - can make us lose concentration and cause us to function less effectively.”

Spatial study

In the new Bradford study, 23 expectant mums and 24 women who were not pregnant were given four special computer based tests to see how well they remembered patterns and locations they’d seen before. They were asked to plan moves and learn rules.

Their memory, spatial recognition, attention and mood and anxiety were measured. Levels of several hormones were also checked.

The pregnant women performed significantly worse on the spatial memory tests.

During the second and third trimesters, and three months after the birth, they scored around 70% compared to around 80% for the women who were not pregnant.

The mood and anxiety scores suggested that pregnant women have lower mood, greater anxiety and greater risk of depression compared to the non-pregnant women. Scores following birth were then the same as non-pregnant women.

Hormone level measurements confirmed substantially increased blood levels of oestradiol, progesterone, cortisol, prolactin and the sex hormone binding globulin, while dehydroepiandrosterone-sulphate levels halved during pregnancy.

The findings

The researchers say their findings help to provide more information on the effects of pregnancy on memory. They say that this increased understanding of the maternal brain may help those who provide care for pregnant women.

Research midwife Diane Farrar of the Bradford Institute for Health Research says in a news release: “Forgetfulness and slips of attention are phenomena commonly reported by pregnant women, but scientists have yet to identify a specific mechanism by which this memory impairment might occur. Indeed, some question whether the reported memory loss exists at all.

“Altered hormone levels during pregnancy may affect brain regions involved in memory processing. Altered mood and increased anxiety, which may be due to altered hormone levels or pregnancy related worries, may also adversely affect memory function.

“More research is now needed to identify the neurological effects of pregnancy to help guide future research and provide information for women and those involved in maternity care.”

The findings will be presented this week at the annual Society for Endocrinology BES conference in Manchester.