The causes of autism spectrum disorders (ASD) are poorly understood. There have been many “culprits,” including environmental pollutants, parental ages, and genetic determinants, but these are at best, theoretical, and at worst, made up. A new study examined the possible influence of another factor—maternal type 2 diabetes, a condition known to have a number of negative consequences for the offspring, including too large babies and various metabolic abnormalities.
Led by Dr. Anny H. Xiang from Kaiser Permanente Southern California in Pasadena, researchers conducted a retrospective evaluation of the frequency of ASD among babies who were born to mothers with type 2 diabetes. The frequency of ASD among 3 groups of babies was compared: first there were nearly 291,000 babies whose mothers did not have diabetes during pregnancy — the control group; second, there were about 25,000 infants whose mothers had developed diabetes during pregnancy; and third, about 6500 infants whose mothers had type 2 diabetes before they became pregnant.
After controlling for a number of factors, such as maternal age, number of births a mother had had, income levels, race/ethnicity, history of other illnesses of the mother, and sex of the baby, there were some differences between the groups. Infants whose mothers had diabetes before pregnancy were not more likely than controls to develop ASD. But if the mothers had gestational diabetes diagnosed at 26 weeks of pregnancy or earlier, their offspring had a significant 42 percent increased risk of being diagnosed with ASD.
ACSH’s Dr. Ruth Kava commented “These results, while needing to be replicated, should be taken as a warning that pregnant women should endeavor to avoid developing type 2 diabetes to the extent possible (and it is not always possible). But maintaining a healthy body weight before becoming pregnant and gaining only a reasonable amount of weight during pregnancy may help prevent the occurrence of gestational diabetes, and perhaps lower the risk of ASD in their babies. We can also speculate, based on these data, that the increased diagnoses of ASD seen in recent years could be related to the recent uptick in overweight and obesity in women.”