February 15, 2003
Question from New York, USA:
I am 36 weeks pregnant with my second child and have been diagnosed again with gestational diabetes. During my last pregnancy, it was controlled with diet, and my doctor never even mentioned that I test for urine ketones, I have a new doctor and diabetes specialist who have me test for ketones every morning. Most mornings I have negative or trace ketones. However, one hour after dinner, when my blood glucose is around 130-140 mg/dl [7.2-7.8 mmol/L], I show large amounts of ketones in my urine. I am only taking insulin before bedtime and have only been doing so for about two weeks. Why are my ketones so high even though my blood glucose is in the normal range? Should I be testing for ketones throughout the day? If so, what results should I expect to see? What effect will the large amounts of ketones have on my baby, if any?
In gestational diabetes, urinary ketones are not a problem and do not represent a risk to the fetus. Ketones in the urine also frequently occur in women without diabetes (starvation ketosis).
The presence of ketones does not necessarily reflect your immediate blood sugar value. You are making insulin, but there is increased resistance to insulin due to the hormonal changes of pregnancy. You are not at risk of developing DKA [diabetic ketoacidosis]. I would not suggest checking your ketones more frequently.