The bleeding that occurs while you take the inactive pills isn't the same as a regular period. Nor is the bleeding necessary for health. This is good news if you take birth control pills and want more control over your menstrual cycle, either for personal or medical reasons.
To prepare for the glucose tolerance diagnostic test: 1  Eat a balanced diet that contains at least 150 grams (g) of carbohydrate per day for 3 days before the test. Fruits, breads, cereals, grains, rice, crackers, and starchy vegetables such as potatoes, beans, and corn are good sources of carbohydrate.
With the OGTT, you cannot eat or drink for at least 8 hours before the test. You will drink a liquid that contains 100 grams of sugar (glucose). Your blood sample is taken 3 hours later to see how much sugar is in your blood. If you don't have a lot of sugar in your blood, you don't have gestational diabetes.