In yet another study underscoring the importance of good maternal health, researchers are now linking, diabetes and hypertension with neurodevelopmental problems, including autism, in children.
Autism spectrum disorders currently affect about 1 in 88 children in the U.S.
"These are associated risk factors -- they are not saying 'causes'," said Alycia Halladay, director of research for environmental sciences with Autism Speaks, one of the nation's largest autism advocacy groups.
"But this is an important study because it identifies maternal health conditions that may be actionable risk factors," she said. "These are things that parents -- specifically women -- can modify."
In the new study, published Monday in the journal Pediatrics, researchers used data from the "Childhood Autism Risks from Genetics and the Environment" study, focusing on about 1,000 children ages 2 to 5. Within that group, nearly 500 children had autism, about 200 had other developmental disorders and 300 were considered normal.
Obese mothers had 1.6 times the chance of having a child with autism and were more than twice as likely to have a child with another developmental disorder.
Maternal diabetes and neurodevelopment disabilities were linked: Moms with diabetes were more than twice as likely to have a child with developmental delays, and their children also did worse on language and communication tests.
Overall, the researchers say their findings raise concerns that obesity, diabetes and hypertension in mothers may be associated with neurodevelopmental problems in children. The potential public health impact, they say, is significant. The prevalence of obesity and diabetes among women of childbearing age in the U.S. is 34 percent and 8.7 percent, respectively.
"We chose these three conditions because they were related," said Paula Krakowiak, a researcher with the MIND Institute at UC Davis in California and one of the study's authors. "The underlying mechanism that we were interested in is one that involves insulin resistance."
The authors hypothesize that in diabetic and pre-diabetic pregnancies, poorly regulated maternal glucose levels can hamper fetal development. Krakowiak also suggested that certain immune biomarkers related to insulin resistance and chronic inflammation can cross over the placenta and impact development of the fetus.
But the researcher also echoed Halladay's caution, stressing that the study does not attempt to -- and cannot -- confirm any condition as a cause.
"In our study, since it's retrospective in nature, we were not able to actually measure biomarkers and see if this is what's going on in these others," Krakowiak said, adding that it is quite possible the associations are simply that. "Those are the limitations, but at the same time, we did see an association in general."
Dr. John C. Pomeroy, division chief of developmental disabilities at the Cody Center for autism and developmental disabilities at Stony Brook Medicine, added that the study is somewhat limited by the nebulous distinction of "other developmental disorders."
"Overall, my sense is that it's telling us that these metabolic conditions -- particularly hypertension, diabetes and obesity -- seem to be general risk factors," he said. "The question of whether or not they're specific for autism, is a little less clear."
But while such questions remain, the experts agree that the study suggests yet another reason why women should take steps to control these metabolic risk factors during pregnancy. This, despite the fact that the current research does not clarify what impact an obese mother, for example, can have in limiting her baby's risk if she is already pregnant, or if that change must come before.
"We certainly don't want to come across saying that overweight women are the reason why children are becoming autistic," said Halladay. "But women who are in these high-risk categories should be seeing health care professionals anyway. As they become pregnant, they can try and manage their blood sugar correctly."
And women should remember that ultimately, while such studies draw attention to the importance of overall maternal health particularly when it comes to their children's neurodevelopmental health, the odds of having a normal, healthy baby are in their favor, reminded Dr. Thomas Wilson, chief of pediatric endocrinology at the Stony Brook Children's Hospital.
"Obviously, autism and developmental disorders are hot topics and everybody would like to know what the causes here," he said. "In the end, it's probably going to be a lot of things."