Advice on taking the 3-hour glucose test

[Alanna]

I am taking my test next wednesday... so i have about a week.

does anyone have any advice to maximize my chances of passing?

the bad m/w at the place i go to (who as you can tell - i dont like) said i should carbo-load in the days before... that seems like exactly the wrong thing to do to me... the lady i spoke to at the hospital who runs the test said that i didnt neeed to do anything diet wise and just to fast from midnight the day before. (im going in at 7:30am)

Thanks for any hints or advice you might have...

[adoredh]

Do you remember what your number was from the 1 hour test?

They want to see it 140 or under, mine was 155 at the one hour test. I fasted from 10pm on, had mine at 830am and was able to pass. Just thought that might make you feel a little better.

(the waitting is a pain through, bring a book to read!)

[alisong]

Keep in mind that you really want an accurate diagnosis, not to maximize your chances of passing - GD can have really bad effects on mom and baby if it's not well controlled.

That said, I was in your position last year, and like you really wanted to "pass". I did (just!), but wasn't given the carbo load instructions, so I restricted my sugar intake in the days leading up to the test. This is exactly the wrong thing to do!

I hope she doesn't mine, but here's a really helpful post lolavix wrote on the subject:

What does this office recommend as far as preparation for the 1 hour GTT?

Just to live your regular life. No special preparation is needed.

What are the effects on the 1 hour test of eating immediately beforehand?
If you eat something within 30-40 minutes of taking the test, your result might be slightly higher than it would have otherwise been.

If you eat something two hours or longer before taking the test, your result might be slightly higher or have no real effect.

However, if you eat something from 40 minutes-2 hours prior to taking the test, your result might be slightly lower than it otherwise would have been.

Why lower?

This is because it takes about 30-40 minutes for food to begin to be digested, carbs to show up in blood sugar, and insulin produced by the pancreas to begin working. Because you have extra insulin in your blood from this food eaten 40 minutes-2 hours prior to the test, it might help lower the effect of the GTT drink.

However, she did say that normally, eating beforehand really would not skew the test so much so that an accurate result could not be determined.

If someone fails the one hour, is there special prep for the three hour?

Yes. In this case, a patient should eat a high carb diet for three days prior to the test.

Why a high carb diet? (I have to say, this ran counter to what I thought and posted, but after hearing her answer, it makes sense.)

If you carbo load in the days leading up to your test, this gives you the best shot of having your pancreas and insulin levels working optimally for you--revs them up, in a way. So, it actually gives you the best chance of passing the test. She said if you don't eat or eat very low carbs, you can actually make yourself more intolerant to glucose and less likely to pass.

I know it runs counter to what you might think, but when you think about the biology, it does make sense.

What would you do, if you failed the 1 hour and passed the three hour?

(Remember, this is coming from an endocrinologist who specializes in diabetic pregnancies.)

She said that she would probably still eat a restricted carb diet.

Her thought is that the cutoffs of the test are somewhat arbitrary. If someone just squeaks by, they might still have a problem with sugar, it's just that on that particular day, they managed to pass and on another day, they might not.

She said that studies and observations have shown that women who fail both the one hour and the three hour who observe dietary restrictions actually have smaller babies (a good thing) than women who fail the one hour but pass the three hour (and hence, don't observe dietary restrictions).

[Alanna]

Thanks for posting that Alisong (and to lolavix too) that makes sense, I hadnt thought of it that way...

[BTB]

I was given a written diet to follow for three days prior to my 3-hr GTT. I wholeheartedly agree with this:

Keep in mind that you really want an accurate diagnosis, not to maximize your chances of passing - GD can have really bad effects on mom and baby if it's not well controlled.

It's not a good idea to try to finagle desirable results, instead of true results - GD is serious for mom and for baby and if present, needs accurate diagnosis because good management improves the outcomes.

[Alanna]

I was given a written diet to follow for three days prior to my 3-hr GTT. I wholeheartedly agree with this:



It's not a good idea to try to finagle desirable results, instead of true results - GD is serious for mom and for baby and if present, needs accurate diagnosis because good management improves the outcomes.


I totally agree with this too... but since I didnt get any guidelines except the vague direction to carbo-load... I was just looking for some guidance so I dont shoot myself in the foot and fail it by a small margin because I made some random bad food decision.

I wish I had a written diet or any written instructions at all. :(

[BTB]

fail it by a small margin because I made some random bad food decision

Don't worry, that won't happen! Your ability to process glucose is not so affected by diet as that. That's why some places don't bother anymore giving written diets. It's not the kind of test you can 'study' for, lol. :)

You'll drink the 100g of glucola and either process it efficiently or not, and if you fail by a small margin rest assured that the margin is such that if you failed by even 1 pt, that is a statistically significant failure and not an "almost got out of jail free" kind of thing. ;)

[IrishEyes]

I failed the 1 hr GTT in a big way (172, when 'passing' was 140) and I had not eaten since the night before.

I did not do anything before the 3 hr GTT (no carbo loading) but did fast again. I passed with flying colors.

I just recommend having food (snack or lunch) on hand to eat once you finish the test. I was shaking from low blood sugar at that point.

[JenniferEC]

I second IrishEyes about having something to eat for when you're finished. Fasting that long made me really shaky and I thought I was going to pass out. I drove straight to a grocery store and bought a few candy bars to keep me from ending up on the floor.

[Brink]

If you failed the 1 hour and passed the 3 hour, do you know what your levels were?

I was told I failed the 1 hour with a 168. Then I took the 3 hour and passed. I just got my results in the mail and they were

1-hour = 171
2-hour = 153
3-hour = 131

Doesn't that sound really high to have passed?

[alisong]

Brink - here are my numbers, plus the numers my doctor uses as cutoffs, plus the numbers the American Diabetes Association uses:

timepoint me kaiser ADA
fasting 76 105 95
1hr 188 190 180
2hr 159 165 155
3hr 57 145 140

(sorry about the crummy formatting)

[Brink]

Thanks alisong - that makes me feel better. I thought I was still on the very high side, but it looks like I'm below the cutoff - so I won't worry or question my doc.

Thanks again.