Sweetened fears

Eating a lot of sugary foods during pregnancy could lead to an increased risk of birth defects, according to research to be published in the American Journal of Clinical Nutrition (AJCN). Mothers who ate a lot of foods with a high glycemic index, which cause a rapid rise in blood sugar followed by a sharp fall, apparently doubled their risk of having children with neural tube defects, such as spina bifida. Obese mothers were found to be four times more likely to have children with such problems.

By focusing on the 'double' or 'quadruple' supposed relative risk of birth defect, the headlines disguise the fact that the absolute risk of birth defect remains very small. Department of Health figures suggest that there are about 800 cases of neural tube defects in England and Wales each year - about one case for every 1000 live births. Most of these cases are detected by routine antenatal screening. The majority of such pregnancies end in termination, so that very few children are born with these conditions.

Studies like the one published in AJCN should never be taken at face value. For example, Andrew Russell of the Association for Spina Bifida and Hydrocephalus told BBC News: ‘The idea that a sugar surge in the maternal blood could cause spina bifida, while not impossible, would need quite a lot of corroboration because there are so many other things that feed into the metabolic process which controls development and closure of the spinal column.’ The safest thing that any parent-to-be can do in relation to reports like these is generally to ignore them.

Whatever the merits of the science, the effect of such news reports is further to increase the nine-month guilt-trip that is pregnancy today. Mothers are already lectured about giving up cigarettes, alcohol and caffeine. Now, it is suggested, they should avoid eating a range of foods from white bread to cooked carrots - despite the fact that the medical basis for most of this advice is shaky at best.

Andrew Russell says: ‘I would not feel at all comfortable about telling a mother that because she ate a cream bun in the early stages of pregnancy she was responsible for her child's lifelong disability.’ Exactly. The stress of such guilt-trips is the last thing an expectant mother needs.

Sugary foods 'birth defect risk', BBC News, 24 November 2003

Folic acid and the prevention of spina bifida: new campaign plans, UK Department of Health, 13 July 1995

(also posted on spiked)