In most cases your Ob will send you for the GCT (GLucose Challenge Test) which is drinking the 300ml of liquid (flat lemonade - even comes in a bottle that reminded me of 7up!). You go back an hour after the drink and get blood taken. Depending on the results of that you may be sent back for the GTT (Glucose Tolerance Test) which is when you are required to fast prior to the test, have the same amount of liquid, and then submit a combination of urine and bloods for testing. If you have had GD before or are high risk for it, your ob might request the GTT straight off but most prefer to begin with the GCT. I was petrified of it too because when I had it years ago, it was a different liquid and was awful! But I found this one ok. HTH

MG