Detecting nocturnal hyperglycemia in pregnant women with gestational diabetes may help to reduce rates of large for gestational age (LGA) infants in this population, according to study results published in Diabetes Care.
Continuous glucose monitoring can provide detailed information regarding the 24-hour day variations in fetal exposure to maternal glucose. To determine if variation in glucose levels affects the development of LGA, researchers conducted a prospective observational study of pregnant women with gestational diabetes being treated at multidisciplinary antenatal diabetes clinics (N = 162). Participants had 7 days of masked continuous glucose monitoring between 30 to 32 weeks’ gestation. Glycemic variability measures and standard summary indices of continuous glucose monitoring were calculated, and differences in temporal glucose profiles were determined by applying functional data analysis. LGA was defined as a birth weight ≥90th percentile for infants after adjusting for gestational age, sex, maternal height and weight, parity, and ethnicity.
Women who delivered an LGA infant had significantly higher mean glucose levels compared with women who did not (6.2 mmol/L vs 5.8 mmol/L; P =.025). No significant differences were observed in percentage of time in, above, or below the target range, or in glucose variability measures (P >.05 for all). Using functional data analysis, higher mean glucose was revealed to be driven by significantly higher glucose levels for 6 hours overnight in mothers of LGA infants (12:00 AM to 6:00 AM: 6.0 ± 1.0 mmol/L vs 5.5 ± 0.8 mmol/L; P =.005). Although mean daytime glucose between 6:00 AM and 12:00 AM was slightly higher in LGA infant mothers, the between-group differences were not statistically significant (6.3 ± 0.6 mmol/L vs 6.0 ± 0.6 mmol/L; P =.058).
Limitations to the study included using only gestational diabetes diagnoses based on criteria from the United Kingdom National Institute for Health and Care Excellence as well as data obtained at 30 to 32 weeks’ gestation.
The study investigators concluded that “nocturnal glucose control is currently overlooked in the management of [gestational diabetes]. Detecting and addressing nocturnal hyperglycemia may help to further reduce rates of LGA infants in women with [gestational diabetes].”
Law GR, Alnaji A, Alrefaii L, et al. Suboptimal nocturnal glucose control is associated with large for gestational age in treated gestational diabetes mellitus [published online February 14, 2019]. Diabetes Care. doi:10.2337/dc18-2212