Diet Soda Guzzlers More Likely to Pop Out Preemies

(July 23) -- The more diet soda women drink while pregnant, the more likely they are to deliver a premature baby.

A study of 60,000 Danish women, published this week in The American Journal of Clinical Nutrition, is spurring renewed interest in the potential for long-term repercussions to a diet loaded with artificial sweeteners.

1. What prompted this kind of out-there study?

Initially, it was a link between diet and sweetened soda and premature births -- which researchers chalked up to high blood pressure, itself a common symptom among women who consume a lot of either kind of drink.

But the team, based at the Statens Serum Institut in Copenhagen, wanted to determine whether there was a direct link between diet soda and preterm births.

So they commissioned a study, asking 60,000 pregnant Danish women to report on their diet, including soda intake, at the midpoint of pregnancy.

2. What were the findings?

Only 5 percent of all the reported births occurred preterm. But among women who reported consuming one soda a day at week 25 of the survey, the rate of premature delivery increased by 38 percent.

And among the devoted guzzlers -- women throwing back four or more daily diet sodas -- premature deliveries soared by 80 percent.

Women's weight and blood pressure weren't found to be associated with the preterm delivery risk.

3. What's aspartame got to do with it?

Aspartame, the oft-maligned artificial sweetener that's been alleged to cause brain tumors, seizures and memory loss by anti-artificial-sweetener advocates, is a key ingredient in many soft drink brands.

But this study didn't evaluate specific artificial sweeteners, so researchers aren't sure whether any one product is tied to the premature birth risk.

That said, aspartame has already been linked to premature births in animal studies. The compound breaks down into methanol during digestion. In 2004, a study in the Journal of Neurotoxicology and Teratology concluded that exposure to the byproduct "significantly decreased" gestation periods in primates.

4. Caffeine, sushi, now diet soda. What's a pregnant lady to do?

Depends who you ask. The Calorie Control Council, a lobby firm for artificial sweetener companies, brushes off the allegation as a "Myth of the Month" on its website.

Moreover, it reminds expectant mothers, sugary sodas might be a threat to an expectant mother's waistline.

"Further, low-calorie sweeteners can help pregnant women enjoy the taste of sweets without excess calories, leaving room for nutritious foods and beverages without excess weight gain -- something that has been shown to be harmful to both the mother and developing baby," reads a statement from the council published by Reuters.

So far, the Food and Drug Administration agrees -- at least tacitly. Several decades ago, the agency approved artificial sweeteners for use among pregnant women, and it's yet to revise or review the stance.

The research team acknowledges that other factors might explain its finding and suggests further research to confirm or invalidate that finding.

Until then, drink up -- or don't -- at your own discretion.