Researchers uncover a link to autism—and it isn’t vaccines

Just as Health Secretary Robert F. Kennedy Jr. has called for an investigation into debunked claims of vaccines causing autism, a massive new study bolsters a body of evidence behind an entirely different link to the neurodevelopmental disorder: gestational diabetes.

The study, out of China and published in the Lancet Diabetes & Endocrinology journal, is the latest to show a connection between diabetes during pregnancy, which affects up to 9% of U.S. pregnancies, and an increased risk not only of autism, but other brain and nervous system problems.

Autism spectrum disorder (ASD) is a developmental disability caused by differences in the brain, according to the Centers for Disease Control and Prevention. While some people with ASD have a known difference, like a genetic condition, other causes are not yet known, and scientists believe there are multiple causes that act together.

While the research—a meta-analysis of data pooled from 202 earlier studies of more than 56 million mother-child pairs—doesn’t show whether gestational diabetes actually causes those problems, it shows that when mothers have diabetes while pregnant, children are 28% more likely to be diagnosed with a neurodevelopmental disorder.

For autism, the risk was 25% higher for children of mothers with diabetes during pregnancy—and 30% higher for attention deficit hyperactivity disorder (ADHD), 32% higher for intellectual disability, 20% higher for trouble with communication, 17% higher for movement issues, and 16% higher for learning disorders—compared to babies whose mothers did not have gestational diabetes.

Further, the researchers noted, having diabetes diagnosed before pregnancy appears to be linked with a 39% higher risk for one or more of those neurodevelopmental disorders than having gestational diabetes, which often resolves with the birth. 

Past research has also found a higher diabetes prevalence in people with autism, and also that people with autism may have a higher risk of developing diabetes. And a 2022 meta-analysis out of the U.K. found evidence of a statistically significant association between ASD and diabetes.

Researchers behind the latest analysis said that more research is needed, and called for “diligent monitoring” of blood sugar levels throughout pregnancy.

This story was originally featured on Fortune.com