Suboptimal Nocturnal Glucose Control Is Associated With Large for Gestational Age in Treated Gestational Diabetes Mellitus

Abstract

Objective: Continuous glucose monitoring (CGM) provides far greater detail about fetal exposure to maternal glucose across the 24 hour day. Our aim was to examine the role of temporal glucose variation on the development of large for gestational age infants (LGA) in women with treated gestational diabetes (GDM). Research Design and Methods:A prospective observational study of 162 pregnant women with GDM in specialist multidisciplinary antenatal diabetes clinics. Participants undertook a 7-day masked CGM at 30-32 weeks gestation. Standard summary indices and glycemic variability measures of CGM were calculated. Functional data analysis was applied to determine differences in temporal glucose profiles.LGA was defined as birth weight ≥90th percentile adjusted for infant sex, gestational age, maternal BMI, ethnicity and parity.Results -Mean glucose was significantly higher in women who delivered an LGA infant (6.2 vs 5.8 mmol/l P=0.025 or 111.6 mg/dl vs 104.4 mg/dl respectively). There were no significant differences in percentage time in, above or below the target glucose range, or in glucose variability measures (all P>0.05). Functional data analysis revealed that the higher mean glucose was driven by a significantly higher glucose for 6 hours overnight (00h30-06h30) in mothers of LGA infants (6.0 ± 1.0 mmol/l vs 5.5 ± 0.8 mmol/l p=0.005; 108.0 ± 18.0 mg/dl vs 99.0 ± 14.4 mg/dl respectively). Conclusions: Mothers ofLGA infants run significantly higher glucose overnight compared to mothers without LGA. Detecting and addressing nocturnal glucose control may help to further reduce rates of LGA in women with GDM.3

Continuous and Intermittent Glucose Monitoring in 2019

“…Importantly, a recent study demonstrated that mothers of large for gestational age (LGA) infants had significantly higher glucose overnight compared with mothers with normal for gestational age infants. Detecting and addressing nocturnal glucose control may help to further reduce rates of LGA in women with GD (20). The efficacy of CGM for GD is yet to be demonstrated in a well-designed RCT, however it seems logical that with proper training and education CGM could help pregnant women with GD prevent delivering LGA babies.…”

Why might pumps fail in pregnant women with Type 1 diabetes?

“… have shown that nocturnal glucose levels increased during the last two trimesters of pregnancy in women with pregestational diabetes who later deliver large‐for‐gestational‐age compared to non‐large‐for‐gestational‐age newborns. They recently confirmed this late pregnancy pattern in gestational diabetes . Nocturnal hyperglycaemia may therefore develop in the last trimester in women who previously had low basal rates of insulin infusion during the first hours after midnight, a rather common profile attributable to the dawn phenomenon.…”

“…This insidious pattern will not be detected by conventional self‐monitored blood glucose, as underlined by Law et al . . By contrast, women on MDI, who usually use NPH as a basal insulin , may be protected from fetal growth acceleration and hyperglycaemia in the middle of the night, due to the action peak 4 h after the injection of NPH .…”

Response to Comment on Law et al. Suboptimal Nocturnal Glucose Control Is Associated With Large for Gestational Age in Treated Gestational Diabetes Mellitus. Diabetes Care 2019;42:810–815

“…We thank Foussard et al (1) for their insightful comments on our recent article (2). We demonstrated that women with gestational diabetes mellitus who subsequently have a large for gestational age (LGA) infant run significantly higher glucose overnight, detectable by continuous glucose monitoring (CGM), at 32 weeks' gestation than those women who do not go on to have an LGA infant (2).…”