No, you can definitely not predict if you will have GD or not! But my midwives (and the OB I saw) all confirmed that of I were GD positive, it would be managed with a low GI diet and watching what I do and don't eat. Seeing as I already did that, I didn't feel the need for the test. I also didn't want unnecessary intervention at my birth because I had GD. Like a I said, a good care provider will be able to monitor you accordingly. I'll try to link my thread, it had lots of helpful answers from both sides of the fence.