Managing diabetes during pregnancy is not easy, whether you have type 1, type 2, or gestational, the form that appears during pregnancy.
Now, researchers have found a link—but not cause and effect—between diabetes during pregnancy and giving birth to a child with autism, the developmental disability marked by communication problems and behavioral and social challenges.1,2
The research confirms some previous findings that type 2 diabetes and gestational diabetes diagnosed early in pregnancy (by 26 weeks) raises the risk of autism in the babies. The new research also finds that having type 1 diabetes raises the risk as well.
"Type 1 appears to have the strongest link, then type 2 and then diabetes diagnosed early during pregnancy," says Anny Xiang, PhD, a research scientist at Kaiser Permanente in Southern California, who led the study.
However, she emphasizes they found only an association, not a cause and effect, and that ''autism is still rare, in general." She also put the risks in perspective for OnTrackDiabetes.
Dr. Xiang's team looked at the medical records of more than 400,000 children, born between 1995 and 2012 at Kaiser Permanente. Of that total, 621 children had mothers with type 1; 9,453 had mothers with type 2; 11, 922 had mothers with gestational diabetes diagnosed by 26 weeks and 24,505 had mothers with gestational diagnosed after 26 weeks.
They tracked the children through electronic health records from age 1 year until either the diagnosis of autism or autism spectrum disorder, until they left the health plan, died or the study end date of December 31, 2017. After a median follow up of about 7 years (half longer, half less), 5827 children were diagnosed with ASD.
Dr. Xiang says it is important to put the risk in perspective—to not only cite the increased risk but what the starting risk is. "Type 1 appears to about double the risk compared to a pregnant woman without diabetes. Type 2 increases the risk by about 40 to 50%. And early gestational diabetes increases the risk by about 30%."
According to the CDC, about 1 in 59 children in the general population have ASD.2 That translates into a prevalence rate of about 1.7%.
So even if the risk is doubled by having diabetes, the prevalence rate would be under 3.5% whether the woman has type 1, 2 or early gestational diabetes. And women diagnosed with gestational diabetes in later pregnancy in this study had no increased risk.
Dr. Xiang says she cannot explain why diabetes and autism risk are linked. They did not have information on how well the women controlled their blood sugar, but she speculates that high blood sugar levels may have long-lasting effects on the fetus' organ development and function which may explain the link. The researchers also point out that other factors—such as risk factors from the fathers and genetics—weren't explored and could play a role.
Until more information is gathered, Dr. Xiang says the best advice is: ''Get the glucose under control."
Women who are pregnant and have diabetes should keep some caveats in mind about the research, says Marina Chaparro, RDN, CDE, MPH, a certified diabetes educator in Miami and founder of Nutrichicos, a bilingual resource to help parents improve their children's nutrition. She is currently pregnant with her second child and has type 1 diabetes. She reviewed the study findings for OnTrackDiabetes.
It is important that the research is repeated in other women, she said, so that they can duplicate the results, the gold standard of good research.
She notes that this is not the first study to find the link, but that their research did focus on the different types. "My takeaway from this is the importance of prenatal health." She notes that the advice to keep A1C (the look back at blood glucose over the past 2-3 months) under 6%, which is often given, is solid as it has been linked with fewer complications to both mother and baby.
Rather than worry about how much diabetes might be increasing the chance of having a child with autism, she says, better for women to focus on keeping the blood sugar under control during the entire pregnancy to stay in the healthiest shape possible.
Dr. Xiang has no relevant disclosures. Marina Chaparro has no disclosures.