Question: how many hours do you have to fast before a gestational diabetes test?
Answer: DO NOT eat or drink anything (other than sips of water) for 8 to 14 hours before your test. (You also cannot eat during the test.) You will be asked to drink a liquid that contains glucose (75 g). You will have blood drawn before you drink the liquid, and again 2 more times every 60 minutes after you drink it.