The association between glycemia, glycemic variability and pregnancy complications in early GDM

Objective: To investigate the association of timing of commencing glucose management with glycemia, glycemic variability, and pregnancy outcomes among women with early gestational diabetes mellitus (GDM).

Research Design and Methods: A sub-study among participants of a trial of immediate vs delayed treatment of early GDM diagnosed by WHO-2013 criteria. All women treated immediately and those with delayed diagnosis at 24-28 weeks’ (treated as if late GDM) were instructed to monitor capillary blood glucose (BG) 4 times/day (fasting and 2-h post-prandial) until delivery. Optimal glycemia was defined as ≥95% of BG measurements between 70-140mg/dl (3.9-7.8mmol/l).

Results: Overall, 107,716 BG values were obtained from 329/549 (59.9%) women (mean age 32.3±4.9years, BMI 32.0±8.0kg/m2, 35% European, gestation at GDM diagnosis 15.2±2.4weeks’). Women treated early (n=213) showed lower mean glucose (MG) and mean fasting glucose (MFG) compared with those treated late (n=116) (MG:5.7±0.4 vs. 5.9±0.5, p<0.001, MFG:5.2±0.3 vs. 5.3±0.4, p=0.004) with greater optimal glycemia (74.6% vs. 59.5%, p=0.006) and similar glycemic variability. The MG was similar from 30 weeks’ gestation. Overall, optimal glycemia was achieved in 69% of women and associated with lower birthweight, decreased large-for-gestational-age infants (14.4% vs. 26.7%, p=0.01) along with increased small-for-gestational-age infants (15.3% vs. 5.9%, p=0.02) and lower gestational weight gain (4.9±6.4 vs. 7.6±6.2kg, p=0.001). Suboptimal glycemia was associated with non-European ethnicity, prior GDM, 1-hour glucose at booking oral glucose tolerance test, and insulin use.

Conclusions: Both early and delayed treatment of early GDM resulted in similar glycemia toward the end of pregnancy; early treatment was associated with improved glycemia overall.