Mean Glucose and Gestational Weight Gain as Predictors of Large-for-Gestational-Age Infants in Pregnant Women with Type 1 Diabetes Using Continuous Glucose Monitoring

Aims/hypothesis: To compare glycemic metrics during pregnancy between women with type 1 diabetes (T1D) delivering large-for-gestational-age (LGA) and appropriate-for-gestational-age (AGA) infants, and to identify predictors of LGA infants. Materials and Methods: A cohort study including 111 women with T1D using intermittently scanned continuous glucose monitoring from conception until delivery. Average sensor-derived metrics: mean glucose, time in range in pregnancy (TIRp), time above range in pregnancy, time below range in pregnancy, and coefficient of variation throughout pregnancy and in pregnancy intervals of 0-10, 11-21, 22-33, and 34-37 weeks were compared between women delivering LGA and AGA infants. Predictors of LGA infants were sought for. Infant growth was followed until 3 months postdelivery. Results: In total, 53% (n = 59) delivered LGA infants. Mean glucose decreased during pregnancy in both groups, with women delivering LGA infants having a 0.4 mmol/L higher mean glucose from 11-33 weeks (P = 0.01) compared with women delivering AGA infants. Mean TIRp >70% was obtained from 34 weeks in women delivering LGA infants and from 22-33 weeks in women delivering AGA infants. Independent predictors for delivering LGA infants were mean glucose throughout pregnancy and gestational weight gain. At 3 months postdelivery, infant weight was higher in infants born LGA compared with infants born AGA (6360 g ± 784 and 5988 ± 894, P = 0.04). Conclusions/interpretations: Women with T1D delivering LGA infants achieved glycemic targets later than women delivering AGA infants. Mean glucose and gestational weight gain were independent predictors for delivering LGA infants. Infants born LGA remained larger postdelivery compared with infants born AGA.