The researchers at the University of California, Berkeley in the US also found obesity prior to pregnancy to increase the risk of neural tube defects (NTD) in babies.
The team carried out a population-based case-control study in California, conducting interviews with the mothers of 454 NTD cases and 462 controls.
Intake of glucose or fructose during the time of conception did not affect NTD risk but intake of sucrose and foods with higher glycemic index values doubled the risk of having a baby with NTD, they reported.
Glycemic index measures the effect of a carbohydrate on the blood sugar and is used by diabetics to help regulate their insulin levels. However it is also gaining interest from nutritionists and dieters as a way of improving cholesterol and heart health. High glycemic index foods include cereals, potatoes, white bread, white rice, while those at the lower end are wholegrains, green vegetables, fresh fruit and whole wheat pasta.
Elevated risks were also observed for high sucrose intake irrespective of whether adjustment was made for other factors involved in NTD risk, such as maternal folic acid intake, added the researchers.
And in obese women (those with body mass index greater than 29) the risk was fourfold, write the authors in this month's American Journal of Clinical Nutrition (vol. 78, no 5, pp 972-978).