'Diet' drinks linked to risk of premature birth

The researchers from Denmark, Iceland and the US, Thorhallur I Halldorsson, Sjurdur F Olsen, Sesilje B Petersen, and Marin Strom, carried out a prospective cohort analysis of almost 60,000 pregnant women in Denmark who took part in the Danish National Birth Cohort study from 1996 to 2002. The intake of soft drinks sweetened by sugar and artificial sweeteners was analyzed to determine if there is any link between these drinks and delivery before 37 weeks.

Soft drinks sweetened with sugar have been associated with various health problems such as weight gain, and because of this artificially sweetened drinks are regularly suggested as a better alternative. The safety of consuming artificial sweeteners during pregnancy has not been established, and there are some indications they may not be as safe an alternative as previously thought.

The researchers assessed the intake of soft drinks in mid pregnancy (at around week 25) using a questionnaire about their consumption of foods and drinks. They also conducted telephone interviews. The drinks covered were carbonated and non-carbonated soft drinks sweetened artificially or by sugar.

The results showed there was an association between the consumption of one or more artificially sweetened soft drinks per day, either carbonated and non-carbonated, and a higher risk of premature birth, over women who did not consume artificially sweetened soft drinks. The risk rose with the number of drinks consumed, and the link was the same in women of average weight and those who were overweight. There was no association for soft drinks sweetened with sugar.

Dr Thorhallur I. Halldorsson, one of the researchers, said it "may be non-optimal" for pregnant women to consume a lot of these artificially sweetened drinks, even though they are often promoted as healthier alternatives to drinks sweetened with sugar. He also noted that soft drinks sweetened by sugar or artificial sweeteners have also been recently linked to high blood pressure, which increases the chances of preterm delivery.

The exact cause of the increase in risk of premature birth is so far unknown, but aspartame has been linked to preterm delivery in animal studies.

The authors of the paper, published in The American Journal of Clinical Nutrition, say further research is needed to confirm or reject the findings. Dr Halldorsson said pregnant women should not be alarmed by the results of the study, but the findings suggest it warrants further research.

More information: Intake of artificially sweetened soft drinks and risk of preterm delivery: a prospective cohort study of 59,334 Danish pregnant women, Am J Clin Nutr (June 30, 2010). doi:10.3945/ajcn.2009.28968

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