Question about GD test

JanaBabe87

So I read a thread on here about GD testing. Today at my doctor's appointment my dr. had said that within the next two weeks I should be tested for GD. I had talked with my midwife about it and she had mentioned that it really isn't necessary. I do however check my blood sugar once a week at my mom's. I don't have diabetes and neither does she. She has a higher blood sugar and the doctor suggested that she get a reader and stuff to monitor her sugars. My sugars have always been great. Ranging from 4.5 to 5.9. My doctor never explained anything about the GD test. How does it work? I noticed on the thread there were some comments about high numbers. What is the number that determines the line for GD? Is it really that important to get it done? My midwife said that if they do say that I have GD then my whole birth plan could change... :S

TIA!