This is why, in addition to overweight babies, the study authors also found that when the babies were born, they tended to have dangerous drops in blood sugar soon after they were breast- or bottle-fed. Their bodies were literally soaking up nutrition at an abnormally high rate -- because they were used to it.
Treatments for GDM include dietary therapy, insulin or pills such as metformin and glyburide -- drugs that don't cross the placenta to the baby.
But are women with borderline-high blood sugar at risk for some of the worst outcomes, like birth defects?
Buchanan doesn't think so, since none of the women in the study had stillborn babies or babies who otherwise died at an early age.
Still, he emphasized that the more pregnant women are studied, the more we will know about what level of blood glucose is associated with problems at birth.
"The relative risk [for those with slightly above normal blood sugar] might be very small. … What we generally do in medicine is set a low threshold and treat everyone."