There have been several attempts to make paracetamol prescription only, due to the side effects and suicide by overdose, but I have never heard of a link to autism.
The only link to medication while pregnant causing autism, was antibiotics. From memory, but no one has really identified the cause of the rapid increase in autism in children.
On the other hand being in Trumps position, may well give him access to a lot of info that isn't in the public domain and he has a history of not being able to keep quiet, so who knows.
The pharmaceutical companies wouldn't want it announced and autism is the fastest growing demand on the NDIS, something is causing the increase in autism.