I'm 6 weeks pregnant. My husband has been told that u/s are bad for baby and can cause autism. Is this true? I really want a us to make sure all is ok

Incorrect. There is no definitive evidence of an ultrasound causing autism that I am aware of.
No. U/s do not cause autism and I have never heard of this. They do not know the cause of autism.
Studied extensively. Ultrasound has been studied over more than 2 decades and no link to autism, birth defects or any other problem has been found. Newer research is pointing to genetic code alternations in the egg or sperm as a potential cause.These may be triggered by environmental exposures long before the pregnancy.