A new study finds that the mothers of children with autism are more than twice as likely as other moms to have had preeclampsia, which involves high blood pressure during late pregnancy. Preeclampsia also increased the likelihood that a child’s autism would be complicated by intellectual disability.
Obstetricians already take preeclampsia seriously as it can develop into eclampsia, a life-threatening condition that often includes seizures.
“This study is important in adding to the large body of research showing that prenatal factors are important in the development of autism,” comments developmental pediatrician Paul Wang, Autism Speaks senior vice president for medical research. (Dr. Wang was not involved in the study.) “We've seen now that prenatal nutritional factors, placental factors and chemical exposures all raise the risk of autism,” he adds. “Parents should not feel guilty about these factors. Many are not under their control. The one clear message from all these studies is that the processes underlying autism can start well before age 1 or 2 and even before birth.”
The findings, by researchers with the University of California-Davis MIND Institute, appear today in JAMA Pediatrics.
The investigators reviewed the pregnancy records of more than 1,000 children enrolled in Northern California’s Childhood Risks of Autism from Genetics Environment (CHARGE) Study. This included more than 500 children with autism, nearly 200 with developmental delays and 350 with typical development.
The analysis also found that the likelihood of autism increased with the severity of the mother's preeclampsia. Mothers of children with autism were also more likely to have had placental insufficiency. This condition hampers the mother’s blood supply to the fetus and can lead to preeclampsia. Both conditions can restrict oxygen and nutrients to the baby’s developing brain.
Because preeclampsia can develop into life-threatening eclampsia, blood pressure monitoring is a routine part of all prenatal checkups. Doctors can take a number of measures to help control the condition. The new findings underscore the importance of high-quality, ongoing healthcare throughout pregnancy.
Also see: "Risk versus Cause in Autism" and "Practical Advice for a Safer Pregnancy."