Fetal Doppler and behavioral responses during hypoglycemia induced with the insulin clamp technique in pregnant diabetic women

Brief episodes of moderate low blood sugar do not appear to affect the fetus of insulin-dependent diabetic women. While it is known that tight metabolic control improves pregnancy outcomes among insulin-dependent diabetics, this results in frequent episodes of hypoglycemia. Ten insulin-dependent diabetic women at gestational ages ranging from 27 to 37 weeks underwent a controlled reduction of blood sugar by infusing insulin. Maternal blood sugar was reduced to 45 mg/dl for 40 minutes. Electronic fetal monitoring and ultrasound imaging evaluated fetal heart rate, fetal practice breathing movements (a measure of fetal well-being), and fetal limb movements. Placental perfusion was evaluated via Doppler ultrasound studies as well. No adverse fetal effects were found. The effects of long-term or severe hypoglycemia on the fetus has not been studied.