July 12, 2001
Question from Ashland, Wisconsin, USA:
I am a 28 years old, and have had type�1 diabetes for 21 years. I am on an insulin pump, and I am approximately 12 weeks pregnant. My hemoglobin A1c is 4.7%, and my endocrinologist wants me to raise my blood glucose levels which this causes me great anxiety. We often hear of the probable adverse affects of hyperglycemia on fetal growth and development and the need for tight control prior to conception and during pregnancy, but can hypoglycemia also be a problem?
The effects of hypoglycemia during pregnancy are not as well studied as hyperglycemia. There are some animal models, but direct study in humans has not been done. Presumably, the fetus responds to maternal glucose levels since glucose easily and readily crosses the placenta. With high glucose amounts, the fetus produces more insulin which contributes to macrosomia (large babies). With low glucose in the maternal circulation, the fetus would have to generate its own glucose. However, reserves in the fetus are probably limited.
Long term consequences of hypoglycemia are unknown. A brief episode of hypoglycemia is probably not significant, much like in the adult. Prolonged and severe hypoglycemia may be harmful. Therefore, in my patients who are having frequent episodes of hypoglycemia, particularly if it requires treatment by someone else, I will decrease the insulin dosing. If you are watching your blood sugars closely and treating any episodes of hypoglycemia promptly, then I would suggest keeping your current regimen as it is.