Measurement of fasting ketonuria and capillary blood glucose after main meals in women with gestational diabetes mellitus: How well is the metabolic picture captured?

Abstract

Metabolic monitoring of women with gestational diabetes mellitus (GDM) usually consists of measuring fasting ketonuria and postprandial capillary blood glucose (CBG) after main meals. We aimed to evaluate how this monitoring system captures the metabolic picture as compared to a scheme with a greater number of time points. Thirty-five women with GDM were recommended to follow a fractionated diet and trained in CBG and ketonuria monitoring. They were asked to monitor ketonuria before a main meal, and to monitor CBG at fasting and 1 h postprandial after any two of the six daily meals. Participants were requested to monitor different meals each day. The goal for 1 h postprandial CBG was <135 mg/dL (7.5 mmol/L). Ketonuria was defined as significant before a certain meal when ≥30% of measurements at that point were positive. Similarly, postprandial CBG was defined as abnormal after a meal when ≥30% measurements exceeded the goal. Ketonuria was significant in 22.5% of the time points and 41.2% of women had significant ketonuria at one or more time points; 61% of the time points and 35.7% of the women with significant ketonuria would have been undetected with monitoring restricted to breakfast. Postprandial CBG was abnormal in 17.6% of meals and 57% of women had abnormal postprandial CBG at one or more meals; 37.8% of points and 15% of women with abnormal postprandial CBG would have been undetected with monitoring restricted to main meals. A substantial proportion of metabolic abnormalities in GDM women are not detected with a monitoring program that measures only fasting ketonuria and postprandial CBG after main meals.