Monday, October 16, 2006

Yet another thing for pregnant women to avoid...

'Mercury may contribute to premature birth' reports New Scientist on research from Harvard School of Health suggesting that eating too much fish increases the risk of giving birth early. 1024 women in Michigan were tested for mercury levels in hair samples. Women who gave birth at least two weeks early were three times as likely to have mercury concentrations of 0.55ppm or above than those who carried their baby for the full term. In turn, women who ate more fish - particularly canned fish - were more likely to have higher mercury levels.

The total number of women who gave birth early in this study was just 44, so drawing any firm conclusions would, perhaps appropriately, be very premature. But more important is the wider issue of how to advise women on what is the best thing to do. Even the lead researcher for this report can see the problems. 'The messages are really very conflicting because fish is both a benefit and a potential source of hazard,' said Dr Fei Xue. Fish is particularly in vogue at the moment because of the high levels of omega-3 oils it contains. But now, eating fish is apparently dangerous, too. Dr Xue recommends fish oil supplements in place of fish as a compromise.

The real problem is the obsession with any potential threat to the health of the fetus at the expense, it would seem, of all other considerations. A recent article by Anna Browning for BBC News summed up the confused and contradictory situation very well. Among the potential hazards she lists are: weight gained during one pregnancy affecting the next one; drinking alcohol; blue cheese; soft cheese; shellfish; caffeine; bagged salad; coleslaw; cigarettes; flax seed; paté; liver; raw eggs; hot baths; lack of folic acid; too much exercise. She could have added eating tuna and avoiding foods with a high glycaemic index, but in truth the list of dos and don'ts is almost endless. Many of them also contradict wider advice about what is good for us.

Women are bombarded with advice about what they should and shouldn't do to the point where they are increasingly reduced to the role of grim incubation. The advice assault doesn't start with conception or end with birth. On the one hand, to become pregnant apparently demands that you are a paragon of healthful virtue, taking regular exercise, eating wholesome food and avoiding fags and booze (despite the obvious link between alcohol and the process of conceiving). After the birth, the pressure from health workers to breastfeed, with all the attendant implications for diet and lifestyle, means that what should be a natural and joyful process has been increasingly turned into an anxious and miserable chore. The irony is that levels of infant mortality and birth defects are far lower than in the past. For example, infant morality in the period 1901-05 in England and Wales was 138 per 1000 births. For 2005, it was just 5.1 per 1000 births.

Heavy drinking and smoking are best avoided, but the risk of any harm from these other factors seems very small - surely no higher than fretting over every mouthful and sip of what passes the lips. Moreover, we should put mothers back at the centre of the equation as human beings with a variety of needs and roles of which carrying a child is just one. If having a baby means that life must come to a crashing halt, fewer women will be prepared to take the risk, denying themselves the undoubted pleasures of parenthood.

Mercury may contribute to premature birth, New Scientist, 13 October 2006

Confused, guilty and pregnant, Anna Browning, BBC News, 2 October 2006