Aim: This study assessed the prevalence of Gestational Diabetes Mellitus (GDM) at booking and its association with age, body mass index (BMI), and ethnicity among at-risk women enrolled in the Treatment of Booking Gestational Diabetes Mellitus (TOBOGM) study.
Methods: Pregnant women with risk factors for hyperglycemia in pregnancy were enrolled at booking (<20 weeks gestation) between June 2017 and May 2018. “GDM” and diabetes in pregnancy (DIP) were diagnosed using the criteria for GDM at 24-28 weeks gestation in the ADIPS 2014 guidelines. “GDM” women were further stratified into low band (fasting 5.1–5.2mmol/L, 1 hour 10.0–10.5mmol/L, 2 hours 8.5–8.9mmol/L), high band (fasting 5.3–6.0mmol/L, 1 hour ≥10.6mmol/L, 2 hours 9.0–11.0mmol/L), and high fasting glucose (HFG) (fasting 6.1-6.9mmol/l) groups based on the IADPSG odds ratios (ORs) of 1.75 and 2.0 for pregnancy complications of GDM diagnosed at 24-28 weeks gestation.
Results: In 638 pregnant women tested, the prevalence of “GDM” at booking was 24.1%. Among those diagnosed with “GDM”, 40.3% were in the low band and 59.7% were in the high band. The prevalence of DIP was 0.6%, with a further 0.6% with HFG. Compared with ‘normal’ women, women with “GDM” were older (p<0.001), heavier (p<0.001) and of non-European descent (p=0.037). GDM low- and high-band groups were similar except for their mean maternal age (30.6 ± 4.9 vs. 32.5 ± 4.1 years, p=0.011). The ORs for “GDM” development were higher in women older than 35 years (OR 3.97 [1.91–8.24]), BMI ≥35kg/m2 (OR 2.42 [1.46–4.02]) and of non-European descent (OR 1.60 [1.10–2.34]) compared with the young, normal weight, European descent reference group.
Conclusion: Preliminary results indicate that the prevalence of booking “GDM” is high among women at increased risk. The association between traditional risk factors and early “GDM” is high in the TOBOGM cohort.