July 20, 2003
Gestational Diabetes
Question from an American living in Mexico City, Mexico:
I am 29 weeks pregnant with my fifth child, I had gestational diabetes during my last pregnancy, and while I feel fairly comfortable in the pre-natal care I am receiving, I am not totally confident in my diabetes management because they did not plan to test me during in this pregnancy until 28 weeks. I started testing myself after meals as soon as I found out I was pregnant (at approximately eight weeks), and my numbers were already over 140 mg/dl [7.8 mmol/L] one hour after meals. Ever since, I have been tightly managing my blood sugar levels with strict diet and exercise, and I test before breakfast and one hour after each meal every day.
My doctor said that the blood sugar levels peak at one hour, and my numbers one hour after meals are always under 140 mg/dl [7.8 mmol/L]. I usually exercise for 20 minutes after each meal (toward the end of the one hour, and out of curiosity, I recently started testing at 30 minutes after my meal, before I exercise. I was shocked to learn that they have as high as the 180-190 mg/dl [10-10.6 mmol/L] range, but when I test at one hour, I will usually be usually be 106-120 mg/dl [5.9-6.7 mmol/L].
I have been managing my diabetes through my entire pregnancy based on the one-hour after meal readings, and my doctor and I thought I was doing great because I am always under 140 mg/dl [7.8 mmol/L]. When I brought this recent issue up with my him, he basically just told me to continue what I have been doing, because I have been very strict with my diet, but I have several questions:
I have been living under the assumption that I was controlling this because my one-hour after numbers were under 140 mg/dl [7.8 mmol/L], not realizing I was spiking to 180-190 mg/dl [10-10.6 mmol/L] at 20-30 minutes. If I had not randomly tested at 30 minutes, I never would have known I was spiking so high, so early. What if this has been happening through my whole pregnancy? Has this done damage to my baby?
How should I test through the rest of this pregnancy? Should I start testing at 30 minutes instead of one hour or test at both?
Would it be better to exercise immediately after my meal rather than waiting 20-30 minutes?
Would I need insulin even though my one-hour levels are below 140 mg/dl [7.8 mmol/L]?
Answer:
Obviously, the more times you check your blood sugar, the more information you have about how your body manages glucose. You appear to have some degree of insulin resistance. In other words, following a meal there is an initial surge in your blood sugar, but your pancreas plays catch up and eventually your body responds to the insulin by bringing your blood sugar down. However, even 140 mg/dl [7.8 mmol/L] at one-hour after a meal is a bit high (I usually use 130 mg/dl [7.2 mmol/L] as a cut off.).
I would suggest that you have a formal glucose tolerance test at your doctors office. If this is positive for diabetes, then appropriate management should ensue: diet, possibly an oral hypoglycemic agent or even insulin. Since there is suspicion for hyperglycemia early in the pregnancy, you should have a good ultrasound review of fetal anatomy around 18-20 weeks as well as a review of the fetal heart around 20-22 weeks.
OWJ
[Editor’s comment: Use of diabetes pills in gestational diabetes is not part of the approved labels for these products. See the discussion about the use of oral hypoglycemic drugs for gestational diabetes at the Diabetes Monitor.
WWQ]
