Back sleeping?

Kristina • Married for 3 yrs, mom to our son born 12/2!
So I am a couple days shy of 14weeks. recently all i want to do is sleep on my back as it is SO comfortable for me!!! however I know it can be bad for the baby cause it can cut off important arteries. Does anyone know if i put a pillow under my knees and elevated my legs a little if that would solve the problem and I could sleep one night on my back ? ty in advance!!