have the flu during pregnancy not associated with a risk of autism or delay of development in children, although having a fever during pregnancy can be.
And delivery by caesarean section is not associated with autism in the progeny, but having diabetes or high blood pressure or being obese, while speakers seem to be.
Those are the results of several new studies that sought to discover what factors during pregnancy can affect the risk of autism in children. The research was presented Wednesday at a press conference at the international meeting for autism (IMFAR) in San Diego research.
About one in 110 U.S. children have an autism spectrum disorder, a condition of neurological development characterized by problems of language, communication and social functioning, as well as repetitive or restrictive behaviour. Many children with autism have also other conditions including epilepsy, anxiety disorders and gastrointestinal disorders.
Recent research has found that the diagnosis of autism is increasing, some of which may be due to greater awareness and increased availability of services for autism, said experts. Still other research suggests that the actual incidence of autism is also rising.
"Autism is a disorder of incredibly complex that now affects about 1% of the children," said the President IMFAR David Amaral.
The cause of autism is unknown, although some research, including the papers presented at IMFAR, referring to maternal factors which could contribute to a child to develop the disease.
In the first study, researchers examined data from research on 1,000 children taking part to the risk of autism from childhood focused on population genetics and the study of the environment (support), 462 included with a spectrum autism disorder136 with other development disorders and 265 typically developing children between 2 and 5. The researchers also examined the reports of the mother of flu or fever during pregnancy.
Researchers found no link between autism and other development and delay the flu in a trimester of pregnancy.
But in a weighted analysis, mothers of children with an autism spectrum disorder were almost twice as likely to report having a fever during pregnancy than mothers of children without autism, co-author of the study Irva Hertz-Picciotto, Deputy Director of the University of Californie.Davis MIND Institute (medical investigation of neurological development).
The risks were particularly high when mothers reported having had a fever during the 2nd quarter.
Prior research has suggested an association between viral infections during pregnancy and autism. Yet researchers believe the mother inflammatory response to the virus, rather than any particular virus itself, influence the development of the brain of the child.
"These results add to a growing number of evidence that inflammation maternally mediated by could be part of the mechanistic pathway leading to Autism", said Hertz-Picciotto.
However, the researchers noted that the findings were preliminary and that the association did not reach statistical significance in an analysis where they did not apply the sampling weights.
Along the same vein, another study to be presented at the meeting by researchers at the Denmark analyzed amniotic fluid collected samples of pregnant women in Copenhagen since 1982. Later, some children from women were diagnosed with autism.
The study found no difference in hospitalization for infections during pregnancy, but they found that mothers of autistic children were more likely to have high level of some inflammatory markers — in particular, a cytokine called TNFa. For reasons not well understood, inflammatory markers were particularly high among mothers of girls with autism.
"Overall, the results of our study not only to support the idea that immune dysfunction plays a role in autism, but also confirm that this happens effectively before birth,"wrote the authors."."
In a third study, mothers who were with diabetes (Type 2 and gestational), which also draws data from the study of the charge, researchers have studied chronic hypertension and obesity before pregnancy.
The study found that children of mothers with these conditions were much more likely to have autism or other developmental delays.
"For mothers with at least one of the three conditions, their children were at risk increased by 60% of autism and delays in development, there was a risk of 150 per cent have increased," Hertz-Picciotto said.
Researchers have also noted that the children of diabetic mothers has also tended to have more poor expressive language skills whether children had autism.
A fourth study, which looked at caesarean section and autism, also used data on approximately 500 children with autism and 300 without autism of the study of the charge.
The study found no link between autism and the delivery method.
However, having a profile in c of emergency after a difficult birth - including prolonged labour, rupture of the membranes or infection of the amniotic cavity - was related to an increased risk of autism in the offspring.
But when the researchers controlled for other factors, such as the age of the mother, pre-eclampsia and diabetes, which are associated with increased risk of autism, the mode of delivery was more statistically significant.
The good news is that many of the factors described in the three studies are "updateable," which means that if they are confirmed to be the Autism risk factors, it would be possible to modify their, Hertz-Picciotto said.
"We would like to able to intervene and potentially avoid autism in the future," she said.
They note that research presented at meetings has not been submitted to the same type of scrutiny given to research published in medical journals and should be regarded as provisional.
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