New research suggests that drinking lots of artificially sweetened beverages may be linked with an increased risk of premature births.
“It may be non-optional for pregnant women to have high consumption of these types of products,” said Dr Halldorsson, one of the researchers on the study.
“Diet” drinks are widely promoted as a healthy alternative to sugary sodas and juices, but Halldorsson and his colleagues note that there’s been little research on the safety of regular consumption of artificial sweeteners in humans.
Soft drinks – both artificially sweetened and sugar sweetened – were recently linked to high blood pressure, the researchers add, which increases the risk of premature delivery. To investigate whether there might be a direct link, the researchers looked at nearly 60,000 Danish women who reported on their diet, including how many soft drinks they had each day, at around 25 weeks of pregnancy.
Around 5% of women delivered their babies before 37 weeks.
Women who had at least one serving of artificially sweetened soda a day while they were pregnant were 38% more likely to deliver preterm than women who drank no diet soda at all, the researchers report in the American Journal of Clinical Nutrition.
Women who had at least four diet sodas a day were nearly 80% more likely to deliver preterm. The association was the same for normal-weight and overweight women.
Because only diet soda was linked to preterm delivery, not sugar-sweetened soda, the findings suggest that the artificial sweetener itself, not soda drinking, could account for the relationship, the researchers say. However, they add, other possible causes for the link can’t be ruled out.
The researchers didn’t look at specific artificial sweeteners, and Halldorsson noted that many beverages contain more than one of these chemicals. However, he and his colleagues say, there is indirect evidence linking the sweetener aspartame to preterm delivery in animals.
Aspartame breaks down into methanol and other substances in the body, which can in turn be converted to toxic substances such as formaldehyde and formic acid, the researchers explain. And studies in non-human primates have linked even very low exposure to methanol to shortened pregnancy and labour complications.