I wonder, in addition to the likely chemical sources, how many more children born early are saved than were in previous decades, and how they may be contributing to this rise.
I know that Surfactant has been around for decades now and I suspect but don't have data that it was the last truly game changing upgrade to NICUs.
The CDC has said with this data "this is up". I think the data is out there to also give a range of reasons and a likelihood for each.
On a personal note, if you suspect your child may be at risk for Autism, early therapy is available and effective. Get it, get it now, get as much of it for your child as you can. My contact info is in my profile and I am happy to point you to the data and assistance.