Preeclampsia tied to higher risk of autism, developmental delay in offspring

By Anne Harding

Children with autism spectrum disorder (ASD) are more than twice as likely as their normally developing peers to have been exposed to preeclampsia in utero, according to a new study.

Mothers who had severe preeclampsia were at more than five-fold increased risk of having a child with developmental delay, Dr. Cheryl Walker of the University of California at Davis and her colleagues report in JAMA Pediatrics, online December 8.

"We controlled for a lot of different factors that might have influenced the results, and it didn't seem to move," Dr. Walker told Reuters Health.

Researchers speculate that ASD results from multiple genetic and environmental "hits", Dr. Walker said, and the new findings show that exposure to preeclampsia is likely one of them. There are many possible mechanisms through which preeclampsia could affect fetal development, she added.

"There are pretty profound changes in maternal physiology, the placenta, and also in what the fetus is exposed to," Dr. Walker said. "In the mom, there is a pretty substantial change in her immune system on multiple levels, there's a broad increase in the level of systemic inflammation, and a great increase in insulin resistance where the pancreas pumps out insulin and the body's just not listening."

The new findings are from the Childhood Autism Risks from Genetics and the Environment (CHARGE) study, a population-based case-control study looking at the origins of both ASD and developmental delay. The CHARGE study includes 517 children with ASD, 194 with developmental delay, and 350 typically developing controls. All children were enrolled between 24 and 60 months of age.

Among the children diagnosed with ASD, 7.7% had been exposed to preeclampsia, versus 5.1% of children with developmental delay and 3.7% of the control group. After the researchers adjusted for education, prepregnancy obesity, and parity, they found an adjusted odds ratio (AOR) of 2.36 for having a child with ASD among the women who had preeclampsia.

When the analysis was limited to women who had severe preeclampsia confirmed in medical records, the AOR for ASD was 2.29, while it was 5.49 for developmental delay. The risk of developmental delay was particularly high among women who had preeclampsia with severe placental insufficiency.

Preeclampsia is associated with poor metabolic function, Dr. Walker noted, with women who are overweight and obese, as well as those with diabetes or underlying hypertension, at increased risk of the pregnancy complication. "It's one more adverse outcome associated with those problems that might give us more ammunition for focusing on maximizing metabolic health prior to pregnancy and during pregnancy," she said.

One important area for future research, according to Dr. Walker, will be to determine whether intervening earlier to treat preeclampsia results in better outcomes, or if the resulting loss in gestational age might be harmful.

The National Institute of Environmental Health Sciences, the Environmental Protection Agency, and the MIND Institute at the University of California at Davis provided funding for the CHARGE study.

SOURCE: http://bit.ly/1wbhHMO

JAMA Pediatr 2014.

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