Glucose control during labour in diabetic women.

Objectives: Glucose control during labour is important for mother and neonate, with high rates of neonatal hypoglycemia reported in offspring of women with pre-existing or gestational diabetes (48% and 19%, respectively). How glucose control can be achieved is rarely specified. We conducted a chart review of a standardized approach using an iterative intravenous insulin-glucose infusion.

Methods: We performed a retrospective review of the records of 274 diabetic women during labour. Fifty-five women had type 1 diabetes, 55 had type 2 diabetes, and 164 had gestational diabetes (GDM). The protocol used hourly capillary blood glucose determinations, each prompting changes in insulin-glucose infusion rates as required. Outcomes included maternal blood glucose levels three hours before delivery and neonatal hypoglycemia (blood glucose < 2 mmol/L).

Results: The insulin-glucose infusion was used in 47% of women with type 1, type 2, and gestational diabetes requiring ≥ 0.5 units/kg/day of insulin during pregnancy and in 8% of women with GDM treated by diet or < 0.5 units/kg/day of insulin. The overall rate of maternal hypoglycemia was low (6.6% with blood glucose ≤ 3.5 mmol/L and 1.5% ≤ 3.0 mmol/L) pre-delivery; 13.9% of women had a blood glucose level ≥ 7.0 mmol/L. The neonatal hypoglycemia rate was 7.3% (4.9% in the offspring of women with GDM and 10.9% in the offspring of women with pre-existing diabetes). In women with type 1 and type 2 diabetes and high-dose insulin-requiring GDM, the rate of blood glucose values outside the range of 3.6 to 6.9 mmol/L was lower in those using the intravenous protocol (16.7%) than in those not using it (34.8%), but this reduction was not statistically significant.

Conclusion: Standardized management for diabetic women in labour using an intravenous insulin-glucose protocol was effective in achieving stable maternal blood glucose levels with low rates of neonatal hypoglycemia.