Maternal glucose variability during pregnancy & birthweight percentile in women with pre-gestational diabetes

Introduction: Pre-gestational diabetes mellitus (PGDM) is a major risk factor for fetal overgrowth. Interestingly, even in relatively well controlled PGDM women, as determined by average glucose indices such HbA1c, there is an increased rate of LGA (large for gestational age). Glucose variability (GV) has emerged as an important independent risk factor for several diabetes complications. The aim of this study was to determine the relationship between maternal GV indices and neonatal birth percentile.

Methods: This was a historical cohort study that included all consecutive PGDM women monitored in a single tertiary care center. Clinical and demographic variables, as well as data regarding glucose control, were prospectively recorded. Mean, standard deviation (SD) and coefficient of variance (CV) of glucose values were calculated. Pearson correlations coefficient was used to determine the correlation between glucose indices and birth percentile. The analysis was repeated after adjustment for several confounders.

Results: Mean birthweight and birthweight percentile were 3212 ± 532 g and 66.9%, respectively. There was a statistically significant correlation between birthweight percentile and maternal glucose SD (β = 0.28, p = .002) and maternal glucose CV (β = 0.21, p = .019). There was no significant correlation between birthweight percentile and mean glucose values. The association between the maternal glucose SD and birthweight percentile remained statistically significant after adjustment for maternal age, pre-pregnancy BMI and duration of diabetes.

Conclusion: There is an association between maternal glucose variability indices (SD and CV) during pregnancy and neonatal birth percentile. Larger studies are needed to confirm these results.