My back pain gets better with hot water bag but now I am scared to use it on my body. I would only use it mildly, still not sure. Did anyone use hot water bag after checking with doctor?
For back or leg pain a warm bag is fine, just keep it warm not too hot and on the back or legs. Never put a hot bag directly on your belly. Thats the main rule.
I used it on my lower back but checked with my gynac first since mine was a careful pregnancy. Avoid the tummy area completely and dont use very high heat. When unsure, just ask your doctor.