Diabetes in pregnant women could lead to autism in babies, according to a new study. Developing gestational diabetes during the first 26 weeks of pregnancy was found to increase the risk of giving birth to an infant who could later go on to develop autism by 63 percent.
Gestational diabetes can be diagnosed in women without a past history of diabetes who experience elevated blood glucose levels.
The new study examined records of 320,000 children born between the years 1995 and 2009 in southern California. Around 2 percent of the mothers suffered from Type 2 diabetes, while 8 percent experienced diabetes brought about during pregnancy.
Autism spectrum disorder (ASD), a grouping of several conditions, including Asperger's syndrome and autistic disorder, was diagnosed in almost 3,400 of the children in the study with 5.5 years of their birth. Even with all other risk factors taken into account, gestational diabetes was found to raise autism risk by 42 percent.
This study does not show that autism is common in babies born from mothers who develop gestational diabetes but that the condition increases risk. For every 1,000 women who develop gestational diabetes, only seven will give birth to babies who will later be diagnosed with ASD.
"Autism is still rare," Anny Xiang of Kaiser Permanente Southern California said.
The reason for the correlation between diabetes during pregnancy and autism is uncertain. One possibility is that high sugar levels affect the development of the brain within the developing fetus during a critical period. Babies born from mothers who develop diabetes after 26 weeks of pregnancy show no elevated risk of developing any form of autism.
"Early in pregnancy that first and second trimester is where the fetal brain is developing. That's a period of time where the brain is most susceptible to insults, so having an elevated blood sugar is an insult to that fetus," Edward Curry of Kaiser Permanante said.
Also unaffected were babies whose mothers knew they suffered from Type 2 diabetes before becoming pregnant. This may be because the women were taking medications to control their disease and continued to do so throughout pregnancy.
Several factors can influence the risk of autism, including the gender of the infant — boys are five times more likely than girls to develop the condition. The age of the mother also influences risk, as does ethnic background, income and past pregnancies.
Asperger's syndrome can commonly result in social, behavioral and communications challenges in people afflicted with the condition.
Analysis of how onset of gestational diabetes can affect autism risk was profiled in the Journal of the American Medical Association (JAMA).
Photo: Mahalie Stackpole | Flickr
