Oral glucose tolerance test result interpretation

Resolved question:

My wife is 24 weeks pregnant and just got the results from the lab on a 3-hour glucose tolerance test, but Dr. is not available until at least tomorrow to talk them through. Having a hard time figuring out what they mean:

Fasting: 77 (95 threshold)

1-hour: 204 (180 threshold)

2-hour: 116 (155 threshold)

3-hour: 41 (140 threshold)

I know they say that two have to be beyond the threshold, and she only has one (the 204). However, what does this mean? That she has partial gestional diabetes? Also, the 41 seems very, very low. Is that a sign of diabetes as well? Is it dangerous? Seems like an extreme swing. Any thoughts would be much appreciated!

Submitted: 4 Days
Category: Diabetologist

Expert:  Dr. J Muthukrishnan replied 4 Days.

Hello and thanks for your queries at Doctor Spring.

Your wife has done glucose tolerance testing for gestational diabetes. Be assured that the test results are negative for gestational diabetes and you do not have cause for concern. The test is designed to test the body's response to a glucose challenge. That is the reason for the initial fasting blood glucose check and then the subsequent checks at 1,2 and 3 hours thereafter. The fasting levels gives a good baseline check and your wife is in the normal range. After the challenge, her levels are spiked up to 204 and although this is high, it is still considered normal. The hormone insulin regulates glucose levels in the blood and her system is working well seeing as how in the hours thereafter, the levels are back to normal.

The lower level at the 3 hour interval should be considered normal and should not cause concern. Understand that there is always some individual variation in each and every person. There is no such thing as partial gestational diabetes, and you either have it or you don't The overall results of the test show that your wife's insulin/glucose regulation is working well and she has tested negative for gestational diabetes. This should put your concerns to rest.

Take care and please ask any follow up questions, if any.

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Patient replied :

Thanks for your response. It says online that if you fail one of the numbers (which she did with the 204 is above 180) yo may have glcose intolerance. Can you tell me what that is? I also hear that sustained high Blood Sugar can negatively affect the baby. Is there any risk that she has that?


Expert:  Dr. J Muthukrishnan replied 3 Days.

Impaired glucose tolerance is a situation where the blood glucose levels are elevated even after 2 hours of a glucose challenge, but not high enough to call it diabetes or warrant treatment. Impaired glucose tolerance can be associated with cardiovascular risks in the future and in some cases can progress to diabetes.

Having said that however, your wife's test results do not meet the criteria for impaired glucose tolerance or gestational diabetes. She would need to have high blood glucose levels even at 2 hours after the glucose load. At 2 hours your wife's glucose levels are returning back to normal, and then have normalized thereafter by the third hour. Yes, sustained high blood glucose can have affects on the baby and is the condition known as gestational diabetes. However, be assured that your wife is not currently at risk for those complications as she has good control over her blood glucose levels. Pregnancy is a metabolically demanding situation under normal conditions. Your wife will need regular visits to her physician to monitor the progress of her pregnancy and ensure that she has adequate nutrition and weight gain ensuring a healthy baby and mother.

Take care and be well. Please ask any questions as follow ups, if any.

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Patient replied :

Thank you. Can I ask you another follow-up question?

My wife recently had her Hematocrit and Ferritin. The Hematocrit results were good (I forgot the number) but the Ferritin was 7, which seems very low. The Dr. said there is is no reason to treat this because the Hematocrit was normal. But the Ferritin seems dangerously low.

What do you think? Does a Ferritin of 7 present any dangers for the pregnancy?


Expert:  Dr. J Muthukrishnan replied 2 Days.

Hello and thanks again for your queries at Doctor Spring.

The reason why ferritin levels are checked is because it can indicate iron deficiency as a cause of anemia. Although her ferritin levels are low, her hematocrit is good as you have mentioned indicating that she is not anemic.

Low ferritin levels have not been associated with adverse affects of pregnancy. Also, supplementation with iron pills has not been shown to provide any benefits of pregnancy when there is no anemia present. I suggest you monitor her hematocrit at each visit to the doctor to make sure she does not develop anemia due to iron deficiency. If her blood count drops, then iron supplementation is warranted.

In the meantime wait and watch. The reason is being is that high levels of ferritin is associated with preterm birth and complications. Iron pills may increase her levels unnecessarily. Conservatively, it is not advisable to treat her for iron deficiency anemia when her blood counts are normal. Work closely with your local physician in monitoring her pregnancy at regular intervals.

Take care and be well.

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