Introduction & Objective: Prior studies do not identify if continuous glucose monitor (CGM) metrics at a critical gestational age (GA) can distinguish risk of adverse pregnancy outcomes (APOs). We evaluated 3rd trimester CGM metrics by GA and APO status in gravidas with type 1 diabetes (T1D).
Methods: Dexcom G6 CGM data from singleton pregnancies with T1D (2018-2022) were retrospectively analyzed. Time in, above, and below range 63-140 mg/dL (TIR, TAR, TBR) and glycemic variability (CV) were computed in 2-week CGM intervals from 28°-396 weeksdays. APOs were hypertensive disorders of pregnancy (HDP), large for gestational age (LGA), NICU admission, neonatal hypoglycemia (NH), and respiratory distress syndrome (RDS). Linear mixed-effects models were fitted on CGM metrics with GA, APO status, and their interaction as fixed effects.
Results: In 86 pregnancies (1st trimester mean HbA1c 6.1%, BMI 25 kg/m2), 71% had at least 1 APO. At 28° weeks, pregnancies with HDP, NICU, or RDS, had higher TAR (p<0.01) and lower TIR (p<0.05). TIR evolution across the 3rd trimester differed in the presence vs. absence of HDP (p<0.05; Figure), with greatest interaction at 28°-316 weeks. Evolution of all metrics differed in the presence vs. absence of RDS (p<0.05), with greatest interaction at 28°-336 weeks.
Conclusion: The early 3rd trimester, a period of peak insulin resistance, is a critical window to optimize CGM metrics to mitigate APO risk.
S.A. Fisher: None. M.F. Villa Tamayo: Research Support; Dexcom, Inc. J. Pavan: Other Relationship; Dexcom, Inc. M. Moscoso-Vasquez: Research Support; Dexcom, Inc. Other Relationship; Dexcom, Inc. C. Fabris: Research Support; Novo Nordisk A/S. Other Relationship; Novo Nordisk A/S, Dexcom, Inc. N. Conboy: None. C.M. Niznik: None. L.D. Yee: None. M.A. Kohn: None. E. Kobayashi: None. A.R. Majithia: None. J. Huang: None. T. Tian: None. R. Aaron: None. D.C. Klonoff: Consultant; Afon Technology Ltd, Better Therapeutics, Inc, Glucotrack, LIfecare, Nevro Corp., Novo Nordisk, Samsung, Thirdwayv Inc.
