A study of 10,000 obese mothers and 5.000 non-obese mothers apparently showed a significantly higher incidence of certain defects, specifically they said Spina Bifida, heart problems and missing toes, fingers etc.
More info here
"Children born to obese women had a 40 percent increased risk for heart defects and more than double the odds of spina bifida."
Have women on mn found this to be the case?