Hello
The real cause of
autism is not really confirmed to our nowadays, but there're some scientific ideas.
The most of scientist believes there's a genetic underlying cause, if there's a sister or brother has autism in the family, that's increases the possibility of having another baby with autism
In 10% of cases, autism associated with genetic disorders.
There's also the environmental causes like exposure to chemicals during the
pregnancy or
oxygen deprivation during delivery but still not confirmed.
About your idea about heavy blankets, it's surely not good for the baby and may cause infant
brain damage.
But still we don't have any confirmation or study about oxygen deprivation and autism after delivery.
What we know actually that the treatment of autistic child by Hyperbaric oxygen treatment (exposing of the autistic child to a high oxygen levels) improves symptoms.
Thank you for asking this question
Wish you the best
Best regards
Dr. Noor Farid