Pregnant women who drink artificially sweetened beverages may be more likely to have overweight infants than women who do not, a study suggested on Monday.

Researchers found that daily consumption of artificially sweetened beverages was linked to a two-fold higher risk of having an infant who was overweight at age one, compared to women who drank no artificially sweetened beverages at all.

"To our knowledge, we provide the first human evidence that maternal consumption of artificial sweeteners during pregnancy may influence infant BMI," said the study led by Meghan Azad of the University of Manitoba.

The report, published in the Journal of the American Medical Association (JAMA) Pediatrics, was based on self-reported survey data.

Therefore, it stops short of proving any cause and effect, but should encourage more research into the matter, scientists said.

More than 3,000 mothers logged their dietary habits, which were later analyzed by researchers.

Their infants' body-mass index was measured at one year of age.

Nearly 30 percent of women reported drinking artificially sweetened beverages while pregnant, but the study did not identify which kinds of sweeteners women were consuming.

Researchers said they controlled for potential confounding factors that could play a role in the baby's weight, such as the infant's sex, whether or not the mother was overweight, and whether or not the infant was breastfed -- and for how long.

The report also found no link between the child's BMI and the pregnant mother's self-reported consumption of sugary drinks.

Previous studies on the matter have been carried out with lab animals.

Some research has found that artificial sweeteners may trigger the appetite and lead to weight gain, or may interfere with important gut bacteria and raise the risk of heart problems.

However, data from observational studies is often conflicting, said an accompanying editorial in JAMA Pediatrics by researchers Mark Pereira, of the University of Minnesota and Matthew W. Gillman of Harvard Medical School.

They described the current findings as "intriguing" but also "preliminary" because they relied on questionnaires, which can contain errors.

Also, the study did not explore the biological mechanisms at play.

"Despite these caveats, the findings by Azad et al warrant attention and further research," they wrote.

"Randomized clinical trials substituting artificially-sweetened beverages for sugar-sweetened beverages or, equally valuable, water for artificially-sweetened beverages would be particularly helpful," it said.