Expectant mother Kate Hilpern doesn’t believe pregnancy affects women’s mental abilities – so what is making her so absent-minded? She goes in search of scientific evidence for ‘baby brain’

So far today, I have put a packet of teabags the fridge, searched the house for my glasses only to find them on my head, and forgotten mid-sentence what question I was asking during a phone interview. It isn’t lunchtime yet.

Some call it “mumnesia”, others have named it “baby brain” or “preghead.” What I want to know, at 36 weeks pregnant, is whether it can really be the case – as some studies suggest – that my brain has shrunk and that I’m likely to be vague and forgetful for up to a year post-partum. Or is the whole notion of “preghead”, in fact, nothing more than a popular myth kept alive by the media – perhaps even a misogynist plot, helping to keep mothers out of the workplace?

“Absent-mindedness is one of the many hallmarks of pregnancy,” states www.babycentre. co.uk, one of the most popular sites for pregnant women, as if it’s an indisputable fact. And like it or not, there’s plenty of research to back this up. One study, conducted by Australian researchers, discovered that mice who were treated with a hormone associated with pregnancy suffered short-term memory loss and changes in motor skills. Meanwhile, a major study last year from the Australian Catholic University in Melbourne – this time on humans – found that the difference in memory skills (not just in pregnancy but well beyond giving birth) could be as great as comparing the mental ability of someone aged 20 with someone aged 60. “What we found is that memory tasks which are more challenging or more novel, or those that would require multi-tasking, are likely to be disrupted,” explains psychologist Julie Henry.

While Henry doesn’t rule out the possibility of hormonal changes as the cause (high levels of oxytocin, a hormone naturally produced by women during pregnancy and while nursing, are known to have an amnesic effect), she’s more convinced it’s related to women being preoccupied with the upcoming birth and and the massive changes to come. “You’re going to have more difficulty sleeping, too,” she says. “And other studies have shown that sleep deficiency definitely disrupts cognitive performance.”

Others point to iron deficiency, which affects many pregnant women, as a possible contributor to forgetfulness. “If the body doesn’t have enough iron, anaemia may occur, and symptoms include fatigue, weakness, irritability and forgetfulness,” says Elaine Hanzak, a specialist counsellor on antenatal care for www.greatvine.com.

Most alarming of all – to me, at least – is the notion of the brain actually shrinking in the third trimester due to hormonal changes. Although a study by the Royal Postgraduate Medical School in London says it plump ups again after the birth, it doesn’t make for comfortable reading.

Pregnant women themselves certainly seem convinced they go ga-ga. According to a report published in the Australian Journal of Advanced Nursing, 82 per cent of the women surveyed reported some type of absent-mindedness or inability to concentrate during pregnancy. “Rare is the midwife that hasn’t had pregnant women reporting it,” confirms Maggie Blott, author of The Day-by-Day Pregnancy Book\[Louisa Saunders\] (Dorling Kindersley)\[Louisa Saunders\] (with McLean believing the dip in brain power lasts years after the birth of a child)\[Louisa Saunders\]In fact, s\[Louisa Saunders\]period of \[Louisa Saunders\]With the prevalence of the myth growing massively in the last 20 years, i\[Louisa Saunders\] video\[Louisa Saunders\]new mothers , says that women should beware that perpetuating the myth of preghead does them no favours in the workplace. “My research shows that for women to be welcome in the workplace, they have to essentially ‘erase’ the maternal body. With pregnancy, the maternal body is obvious and therefore likely to be treated as deviant from workplace norms. Just as male bodies are associated with rationality and solidity, women’s pregnant bodies are associated with unpredictability and emotional and uncontrolled behaviour. As a result, people seem to think it’s OK to make inappropriate assumptions, including you being intellectually impaired. In reality some women find that at certain points in their pregnancy, they are full of energy and highly productive.”

I still don’t know what to believe. The phenomenon of preghead is now widely accepted, even by many feminists, and part of me can’t help thinking I only deny it when it’s inconvenient. On the other hand, I think the whole idea of pre-menstrual cognitive changes is a patriarchal conspiracy, so why should this be any different?