Early Diagnosis of Prediabetes among Pregnant Women that Develop Gestational Diabetes Mellitus and Its Influence on Perinatal Outcomes.

Objective: Purpose of this study was to determine whether early identification of impaired glucose tolerance consistent with prediabetes among pregnant women with gestational diabetes mellitus (GDM) in the first trimester impacts maternal and neonatal outcomes.

Study Design: This was a retrospective cohort study of patients who were screened for pregestational diabetes in early pregnancy at a large academic tertiary care center from October 1, 2017, to January 31, 2021, and who subsequently developed GDM. Demographic and perinatal outcomes were compared among women with GDM with a positive early diabetes screen consistent with prediabetes to women who screened negative in the first trimester. Multivariable logistic regression was performed to adjust for baseline demographic differences.

Results: During the study period, 260 women screened had negative first trimester diabetes screening and subsequently developed GDM, while 696 screened positive for prediabetes and developed GDM. Women with prediabetes were more likely to require insulin treatment for their GDM compared with those that screened negative (79.5 vs. 45.4%,  < 0.001), while those who screened negative were more likely to take an oral medication of metformin or glyburide for GDM management than those with prediabetes (41.5 vs. 16.4%,  < 0.001). Infants born to mothers who screened positive for prediabetes were more likely to require neonatal intensive care unit (NICU) admission compared with those who screened negative even when adjusted for type of GDM treatment used (adjusted odds ratio [aOR] = 8.5, 95% confidence interval [CI]: 1.5-49.9).

Conclusion: Women identified as having early impaired glucose tolerance consistent with prediabetes that subsequently develop GDM are more likely to be prescribed insulin treatment and may be at increased risk of adverse neonatal outcomes leading to NICU admission than women with negative first trimester diabetes screening. Future studies should focus on whether different methods of early treatment and/or intervention improve perinatal outcomes.

Key Points: · Prediabetes in early pregnancy is associated with higher rates of insulin treatment for GDM.. · Prediabetes in pregnancy increases the risk of developing GDM.. · Prediabetes in early pregnancy is associated with higher rates of NICU admission..