Pre exsisting condition

My insurance does cover wls if medically necessary. my question is would it fall under pre existing condition?

I have not heard of it being categorized as a pre existing condition.  As a matter of fact, there are some insurance companies that require documentation of a high BMI (morbid obesity) for a certain number of years before they will consider the WLS.  Their definition of "medically necessary" most likely will include specific evidence of necessity (high BMI, co-morbidities, etc).