(140) Continuous glucose monitoring (CGM) with poor glycemic control correlates to increased risk of preterm birth/preeclampsia

Objective: We evaluated the association between glycemic control derived from CGM in patients with diabetes and the risk of adverse maternal/neonatal outcomes.

Study Design: We performed a retrospective cohort study of pregnant people with gestational and pregestational diabetes using CGM, who received care in a university-based MFM practice and delivered between July 2020 to December 2022, to evaluate the association between glycemic control and maternal/neonatal outcomes. CGM data was downloaded from the proprietary website and analyzed using a modified version of the iglu package using R. Maternal and neonatal demographic and pregnancy outcomes were abstracted from the EMR. Multivariable logistic regression was used to evaluate the relationship between glycemic control with maternal/neonatal outcomes.

Results: We evaluated 92 pregnancy episodes. HgbA1c was negatively correlated with time in range, composite glucose index and gestational age at delivery. HgbA1c was positively correlated with time above range, median glucose, GMI (vector of glucose measurement) and mean amplitude of glycemic excursion. Given high multicollinearity among CGM indices (VIF >24), we focused on GMI as a predictor. In simple logistic regression models, GMI was not significantly associated with: NICU admission (p=0.23), LGA infants (p=0.54), or SGA infants (p=0.29). However, GMI was associated with PTB< 37w (OR 5.67, p< 0.002) and preeclampsia (OR 4.07, p< 0.005). In multivariable logistic regression models, GMI remained a significant predictor of PTB< 37w (aOR 5.50, 95% CI, 1.47-20.59, p< 0.02) and preeclampsia (aOR 3.56, 95% CI, 1.20-10.58, p< 0.03). Among the 34 preterm births noted in our cohort, 58.8% were noted to be iatrogenic and 41.2% were spontaneous.

Conclusion: We found that worsening glycemia in pregnancy was correlated with an increased risk of spontaneous and iatrogenic PTB and preeclampsia. Use of CGM in pregnancy has the potential to revolutionize diabetes care to provide a unique tool for patient education and targeted adjustments in medication therapy but more research is required to guide clinicians in its use.