Introduction and Objective: PE causes morbidity and mortality in women with T1D. Methods: Data were obtained from 5 IRB-approved pregnancy studies. T1D pregnancies with CGM use ≥60% were included. Continuous glucose monitoring (CGM) metrics (pregnancy time-in-range (pTIR), time-above-range (pTAR), and mean sensor glucose MSG), HbA1c, mean systolic and diastolic blood pressure (SBP and DBP) were collected by trimester and overall in pregnancy. Separate multivariable logistic regression models were fitted to assess associations between individual exposures and PE by time period, adjusted for confounders, and reported as odds ratios (OR) with 95% confidence intervals (CI). Results: Among 171 pregnancies, 37 (21.6%) developed PE. In first and second trimesters, lower pTIR, and higher pTAR and MSG were significantly associated with increased odds of PE (Models A, B, and D, p0.01 for all, Table), independent of T1D duration and BP. Mean HbA1c demonstrated strong, independent associations with PE across all trimesters, especially in the second trimester (OR 2.62, 95% CI 1.45-5.00, p = 0.002). T1D duration was associated with PE risk in early and mid-pregnancy, while mean SBP and DBP were not. Conclusion: Optimizing glycemia is critical early in pregnancy as CGM metrics were most strongly associated with PE in early and mid-pregnancy in women with T1D. HbA1c demonstrated consistent associations across trimesters. Disclosure K. Valdez: None. S. Polsky: Research Support; Current; Leona M. and Harry B. Helmsley Charitable Trust, National Institute of Diabetes and Digestive and Kidney Diseases, JDRF, University of Colorado. Other - honoraria for speaking engagements; Current; Children's Diabetes Foundation. Other - honororia for speaking engagements; Current; American Diabetes Association. Board Member; Current; American College of Diabetology. Other - unpaid work to write articles for online publication; Ended; diaTribe. Research Support; Ended; Dexcom, Inc. Other - travel and lodging expenses paid for a meeting; Ended; Insulet Corporation. Other - honororia for speaking engagements; Current; AACE. D. Cengiz: None. S. Maclean: None. M.P. Klein: None.
VALDEZ et al. (2026) studied this question.