Children born to women who suffered a high blood pressure condition called pre-eclampsia during pregnancy are twice as likely to have autism or other developmental delays, US researchers said Monday.
The study in the journal JAMA Paediatrics, a journal of the American Medical Association, also found that the more severe the pre-eclampsia, the higher the likelihood of autism.
The research involved more than 1,000 children aged two to three in northern California. All of their mothers had confirmed diagnoses of pre-eclampsia, and scientists compared data about those developing normally to those with autism spectrum disorder (ASD) or other developmental delays.
"We found significant associations between pre-eclampsia and ASD that increased with severity," said senior author Cheryl Walker, assistant professor in the department of obstetrics and gynaecology at the University of California, Davis.
"We also observed a significant association between severe pre-eclampsia and developmental delay."
Read: Pre-eclampsia increases cerebral palsy risk
Autism spectrum disorder affects as many as one in 88 children in the United States.
The exact causes of the developmental disorder are unknown, with research pointing to genes, the environmental, or both.
Autism leads to difficulties in social, emotional and communication skills, and has no known cure.
Some past research has suggested that pre-eclampsia - which causes high blood pressure late in pregnancy and high levels of protein in the urine, as well as seizures in severe cases - could be linked to autism, perhaps by depriving the foetus of nutrients and oxygen.
"While single studies cannot establish causality, the cumulative evidence supports efforts to reduce pre-eclampsia and diminish severity, to improve neonatal outcomes," Walker said.
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Image: Doctor measures blood pressure of pregnant woman from Shutterstock