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.

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 (TIRp), time above range, time below range in pregnancy, coefficient of variation (CV) throughout pregnancy and in pregnancy intervals 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 three months post-delivery.

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=0.02) compared to 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 three months post-delivery, infant weight was higher in infants born LGA compared to 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 post-delivery compared to infants born AGA.