First trimester Ultra Sound

Hello!

Wondering if anyone had any good sources of information for the safety of Ultrasounds in the first trimester.

My mother-in-love has long believed there is a connection between Ultrasounds and Autism and now it seems there is beginning to be research that may back up this connection. However, wading through the medical articles becomes daunting and confusing as it seems they are still unsure.

My dr has scheduled an "early ultrasound" at 8 weeks because my last pregnancy ended in a miscarriage (around week 11). I want to defer to the dr but I'd also like to be informed. Does any one have a strong source of information on this?