Twice-Daily vs 4-Times-Daily Glucose Testing in Women With Gestational Diabetes Mellitus: A Pilot Study

In women with gestational diabetes mellitus (GDM), glycemic control is typically assessed by capillary blood glucose (BG) self-monitoring. Currently, the standard method of monitoring is by 4-times-daily self-measurements. The goal of our study was to determine whether twice-daily capillary BG testing is comparable with 4-times-daily testing in women with GDM.

Thirty-two women with GDM completed initial dietary counselling and recorded consecutive fasting and 2-h postprandial BG over a 14-day period. We randomly selected 2 of 4 BG measurements on each given day and compared mean (95% confidence interval [CI]) twice-daily vs 4-times-daily BG measurements using paired t tests and Bland-Altman plots. The proportion of 14-day BG measurements above glycemic targets was also compared between twice-daily vs 4-times-daily testing for fasting and postprandial readings.

Comparing twice-daily vs 4-times-daily mean BG, there was a small difference for fasting BG (0.09 mmol/L; 95% CI, 0.03 to 0.14), but not for 2-h postbreakfast (-0.05 mmol/L; 95% CI, -0.17 to 0.06), 2-h postlunch (-0.03 mmol/L; 95% CI, -0.13 to 0.08) or 2-h postdinner (0.05 mmol/L; 95% CI, -0.09 to 0.19) BG. Bland-Altman plots showed general agreement and minimal bias between twice-daily vs 4-times-daily BG, whether fasting or postprandial. There was no significant difference in the proportion of 14-day BG measurements above glycemic targets comparing twice-daily vs 4-times-daily testing in the fasting or postprandial states.

Twice-daily BG testing appears to generate 14-day average values similar to 4-times-daily BG testing. In women with GDM, whose BG is in target range, twice-daily BG monitoring may reduce inconvenience and cost.