Mortgage insurance covers the balance of your mortgage in the event of an untimely death. It is typically a declining life insurance policy. As you pay down the balance on your mortgage, the insurance insurance benefit decreases at the same rate. Premiums will stay the same.
Having a personal term life insurance policy can cover the entire mortgage balance and coverage will not decrease over time.
There are also options to add disability coverage to cover the monthly payments if you became disabled due to an accident or illness and unable to work.