September 1, 2000
Question from Columbia, South Carolina, USA:
I am almost 33 years old. This is my first pregnancy. My pre-pregnancy weight was 118, and now, at 27 weeks, I'm about 123 pounds. I don't smoke, don't eat sugars, I exercise, and I have no family history of diabetes. My one-hour glucose tolerance test showed a level of 158 mg/dl [8.8 mmol/l]. My doctor says that 134 mg/dl [7.4 mmol/l] is their "normal cut-off range", and they are insisting that I submit to the three-hour screen. Are there alternatives to the three-hour fasting screen? I am not interested in physically stressing myself and my unborn child by fasting for almost 18 hours while they conduct this artificial test to see how I metabolize processed sugar water. Aren't there better, non fasting ways to test more accurately how my body metabolizes sugar?
The 100 gram, three hour test is the current recommendation for diagnosing gestational diabetes. Eight hours of fasting is adequate. It is important to measure the fasting blood sugar to make sure that you do not have an elevated blood sugar event without eating. If the fasting sugar is elevated then insulin may be required.
The situation is artificial, but the purpose is to determine how well your system can manage a glucose challenge or stress (100 grams of glucose is just a little more than two cans of soda). There is no adverse effect on the baby.
Another option for you to discuss with your physician would be to just start you on a special diet (low fat, high protein, high complex carbohydrate) and check your blood sugar just before and one hour after breakfast on a weekly basis during the pregnancy. As long as the fasting is less than 105 mg/dl and the post meal is less than 130 mg/dl then this would be adequate management. This approach would not be diagnostic but at least would let you know that your blood sugar is being well controlled.