Pregnancy Outcomes in Patients with Type 1 Diabetes Using Continuous Glucose Monitoring

Continuous glucose monitoring (CGM) use among patients with type 1 diabetes mellitus (T1DM) has been associated with improved glycemic control, though improvement in non-glycemic outcomes is less consistent. We hypothesize that CGM use in patients with T1DM in a real-world clinical setting is associated with both improved glycemic and clinical outcomes.

This was a retrospective cohort study of patients with T1DM receiving care at a large health system from 2016 to 2023. Primary outcomes included (1) glycemic control and (2) a composite comprising severe maternal morbidity, preeclampsia with severe features, delivery prior to 34 weeks, and admission for diabetic ketoacidosis. Primary glycemic outcome was hemoglobin A_1c (HbA_1c) <6% in the second trimester. We compared patients using CGM, our exposure group, to patients using traditional blood glucose monitoring (TBGM). During initial data abstraction, we noted variation in CGM target blood glucose settings. A subgroup analysis was performed in which patients using CGM were evaluated by device setting, with those set to targets consistent with American Diabetes Association (ADA) recommendations compared with those with more permissive goals. Adjusted odds ratios were calculated using multivariable logistic regression to adjust for potential confounding variables.

Among 288 patients with T1DM, there were 145 deliveries in the CGM group and 143 in the traditional capillary blood glucose monitoring group. Midtrimester on-target glycemic control was improved in the CGM group compared with traditional monitoring (40.7 vs. 17.5%, adjusted odds ratio [aOR] = 2.32; 95% confidence interval [CI]: 1.21-4.12). There was no difference in the rate of the composite outcome (CGM: 42.8% vs. TBGM: 49.0%, aOR = 0.70; 95% CI: 0.40-1.22), nor was there a difference in secondary outcomes. In patients using CGM, those with stricter targets had improved glycemic control as well as reduced rates of preterm delivery prior to 37 weeks (18.8 vs. 56.9%, aOR = 0.16, 95% CI: 0.05-0.48) and neonatal intensive care unit admission (37.5 vs. 60.0%, aOR = 0.37, 95% CI: 0.14-0.96).

CGM use in T1DM is associated with improved glycemic control throughout pregnancy; however, this does not uniformly translate to improved clinical outcomes. Lack of adherence to ADA blood glucose targets may contribute to these findings.

· Glycemic control in pregnancy is improved with CGM use in patients with T1DM.. · CGM use does not translate to consistent improvement in clinical outcomes.. · Stricter CGM targets are associated with improvement in glycemic control and some clinical outcomes.. · Simply prescribing an intervention does not automatically lead to benefit..