Tracy Packiam Alloway, PhD

So this week I have burnt the pasta (twice!), put the milk away in the cupboard with the glasses, and locked the car and house keys in the car. If you asked me in my six-month of pregnancy whether pregnancy brain is a myth, I would say NO!

Some pregnancy women blame such actions as the result of the lack of sleep. However, it seems that I can’t use sleep deprivation as an excuse for my forgetfulness. Studies have found that the lack of sleep is not actually linked to memory loss and forgetfulness in pregnant women.

Thankfully, there is a reason for my new (and unwanted!) absent-minded brain. Scientific studies show that during pregnancy, a woman’s brain changes*. For starters, the hippocampus, which is linked to spatial memory and long-term knowledge, actually shrinks during pregnancy. This means that a pregnant woman’s sense of direction is not always as reliable as it used to be.

Why does the pregnancy brain shrink? The brain shrinkage is the result of hormone changes during pregnancy, especially in the final trimester. Some hormone levels, such as progesterone and estrogen, rise and fall during pregnancy. We need a perfect balance of these hormone levels to use working memory-our ability to incorporate new information with long-term knowledge stores. When estrogen are very high, such as during the last trimester of pregnancy, working memory is not as efficient. This makes simple tasks like remembering that the milk goes in the fridge (and not the cupboard) or juggling multiple tasks at work a little more difficult than usual.

Happily, brain size goes back to normal after the baby is born. Pregnant women can be confident of performing to their usual cognitive capabilities, but be aware that the pregnancy brain means that they may be more affected than usual when taking on additional responsibilities.

From TRAINING YOUR BRAIN for Dummies (due Dec 2010)

* Galea et al. (2000). Hormones and Behavior.

We have all heard the rumors: the first thing to go in pregnancy isn’t our waist, it’s our memory! We know the symptoms: missed appointments, misplaced keys, and forgotten errands. Is ‘pregnancy brain’ to blame?

Working memory refers to our ability to remember and juggle information. There are two reasons why we feel our once-fantastic skills at juggling multiple tasks have now disappeared. Scientific studies have recently confirmed that during pregnancy, a spike in various hormones, including estrogen, leads to working memory decline. Pregnant women in their third trimester are particularly prone to working memory loss.

Another factor that contributes to working memory loss is distraction. Information in working memory is fragile and can be lost quickly. During pregnancy, we are likely to be more distracted than usual in planning for the arrival of our little one and coping with impending changes.

Is there anything I can do to help/support myself?

Be patient: Give your body time after pregnancy and nursing for your hormone levels to adjust. It may take a while but the negative effect of increased hormonal activity on working memory is reversible. In the meantime, some find it helpful to use word associations or mental pictures to help them remember. If that’s too much effort, the easiest thing to do is carry a notebook and pen to write things down.