August 25, 2003
Gestational Diabetes
Question from Nashville, Tennessee, USA:
I am 35 years old, 31 weeks pregnant with our first baby, and I was diagnosed with gestational diabetes two weeks ago. I also have high antiphospholipid a antibodies (APAs) for which I take heparin twice per day.
My fasting glucose at 95-102 mg/dl [5.2-5.7 mmol/L] is higher than it should be, and all of my postprandial readings are in the low normal range (85-105 mg/dl [4.7-5.8 mmol/L]). However, my doctor is threatening to put me on insulin if this continues. While I am obviously comfortable with injections at this point, I don’t want to take anything that is not needed, and after four miscarriages, don’t want to mess with a formula that’s working.
Why is fasting glucose so important? I’ve done a lot of research to date on this question, but I can’t find the answer. My obstetrician says it’s important but isn’t giving me any reasons. I thought that the significant problem in gestational diabetes was that blood glucose levels over about 130 mg/dl [7.2 mmol/L] cause macrosomia and shoulder dystocia. So why should a fasting level that’s higher than normal be a problem if it’s not in the very high range? Also, I don’t understand why i’m allowed to have two-hour postprandial levels that are higher than my fasting level.
Answer:
The fasting blood sugar is another measure of how well your body manages glucose. If both the fasting and postprandial glucose values are elevated, that shows that your body can never bring your blood sugar into the normal range. If the fasting is normal but the post-meal is elevated, that suggests that you struggle to bring your blood sugar down after a meal. The first situation always requires insulin, and the second sometimes necessitates insulin if diet adjustment is not working.
It is expected that the post-meal value will be higher than a fasting because of the calorie intake with eating. If you checked your blood every hour after you ate, you would see that the glucose would gradually drop to a fasting value prior to the next meal. Even mild hyperglycemia can result in a large baby, although this is not always the case.
You seem to be under fairly good control and maybe just some diet adjustment will satisfy your doctor. If you are started on insulin, it will not cross the placenta and have any direct effect on the baby. This is unrelated to the APA syndrome for which you are taking heparin.
OWJ
