Glucose testing is performed in early pregnancy to identify women with undiagnosed overt diabetes.1,2 Glucose levels considered diagnostic of gestational diabetes (GDM) at 24-28 weeks gestation may be present in the first trimester, but it is unclear if this predicts GDM, or if treatment of these women improves materno-foetal outcomes.3,4,5,6
A prospective observational audit (January to December 2017) was performed of women referred to our service with fasting plasma glucose (FPG) 5.1-6.9mmol/l in the first trimester. Women with pre-existing diabetes, overt diabetes, twin pregnancy, and those taking diabetes medication were excluded. Demographic data was collected. Women were categorised based on FPG as having lower glucose (LG: 5.1-5.5mmol/l) or higher glucose (HG: 5.6-6.9mmol/l) levels. Pre-specified maternal and foetal outcomes were recorded.
Twenty-six women were included in the analysis (LG n=17; HG n=9). Women in the HG group were more likely to have BMI>30kg/m2 (89% vs 41% p=0.04). A subsequent diagnosis of GDM was made in 78% HG women and 59% LG women in 2nd/3rd trimester; higher than local population prevalence of (17%).
The neonates of HG women were of similar weight (3419±454gm) to those of LG women (3683± 440gm; p=0.16). Average birth-weight (3592±462gm) was higher when compared to neonates born to women with treated T2DM in our unit (n=49 3077± 954gm; p=0.01).7
Macrosomia (birth-weight ≥4kg) did not occur in HG neonates, but was present in 24% of LG neonates. Adverse neonatal outcomes (composite of neonatal intensive care admission, respiratory distress or requirement of continuous positive airway pressure and shoulder dystocia) occurred in 22% HG group and 53% LG group (p=0.42).
This data suggests that early fasting hyperglycaemia may not be a benign condition. A high proportion of women went on to develop GDM. Neonates had a higher birth-weight when compared to women with treated T2DM; adverse outcomes were seen frequently in both HG and LG women. Further studies are needed to guide the management of these women.6