Factors associated with higher risk of small-for-gestational-age infants in women treated for gestational diabetes

BackgroundPreviously, management of gestational diabetes (GDM) has focused largely on glycaemic control, with a view to reduce the occurrence of large-for-gestational-age (LGA) infants. However, tight glycaemic control in GDM is associated with a higher incidence of small-for-gestational-age (SGA) infants, which has been linked to higher rates of adverse outcomes. AimThe aim was to characterise risk factors associated with having an SGA infant in women being treated for GDM. MethodsThis was a retrospective observational cohort study of 308 women with GDM. Women were split into groups based on their infant's size at delivery (SGA, appropriate-for-gestational-age (AGA) or LGA). Literature review and expert opinion helped to determine several predictors of women with GDM delivering an SGA infant, and statistical analysis was used to produce odds ratios (OR) for these predictors. ResultsThe sample included primiparous women with a mean pre-pregnancy body mass index (BMI) of 25.72 (standard deviation: 5.75). Metabolic risk factors associated with delivering an SGA infant included a lower pre-pregnancy BMI (adjusted OR 1.13, P = 0.04, 95% confidence interval (CI): 1.01-1.26), a lower fasting blood glucose level (BGL) (adjusted OR: 3.21, P = 0.01, 95% CI: 1.30-7.93) and growth that was high risk for SGA at baseline ultrasound scan (USS) (adjusted OR: 7.43, P < 0.001, 95% CI: 2.93-18.79). ConclusionsThe combined clinical picture of lower pre-pregnancy BMI, fasting BGL and baseline USS growth measurements may indicate a need for less aggressive glucose management in women with GDM to prevent SGA infants.