Heating pads?

Bekah • 27 and married, mom of a 5 year old son, and a 1 year old girl, soon to be mommy of sweet baby number 3!
I'm 13 weeks pregnant and all I ever want to do is lay on my heating pad! I have some serious back pain that gets worse when I'm pregnant and this really helps, but I don't want to cook the baby! I was just in the hospital for a few days and the nurses gave me a heating pad the whole time so it can't be too bad right?