The role of Amniotic-Umbilical-to-Cerebral ratio (AUCR), a new index, for predicting composite adverse perinatal outcomes in patients with gestational diabetes mellitus: a case-control study

BACKGROUND: To investigate Doppler parameters, including Amniotic Fluid/Umbilical Cerebral Ratio (AUCR), in patients with gestational diabetes mellitus (GDM) and to determine which indices best predict composite adverse perinatal outcomes (CAPO) in GDM. METHODS: This prospective case-control study included 70 insulin-treated GDM patients and 70 healthy controls from a tertiary referral center between December 2023 to April 2024. Ultrasonographic evaluations comprised single deepest vertical pocket (SDVP) and Doppler indices of the middle cerebral artery (MCA) and umbilical artery (UA). Derived ratios, including the cerebro-placental ratio (CPR), umbilico-cerebral ratio (UCR), and the AUCR, were compared between the study and control groups, as well as within the GDM group based on the presence of CAPO. RESULTS: AUCR and SDVP were significantly higher in GDM patients compared to controls (p = 0.009 and p = 0.042, respectively). In the GDM group with CAPO, SDVP and AUCR values were also higher than in the non-CAPO group (p = 0.022 and p = 0.005). In contrast, there were no statistically significant differences in UA PI, MCA PI, CPR, or UCR values either between the GDM and control groups or between GDM patients with and without CAPO (all p > 0.05). ROC analysis showed AUCR predicted CAPO at a cut-off of 10.050 (AUC = 0.703). CONCLUSION: AUCR is a promising ultrasonographic parameter for predicting adverse perinatal outcomes in GDM patients. Given that conventional Doppler parameters did not show significant differences in this study, AUCR may offer an additional tool for identifying GDM cases at risk for adverse outcomes, particularly in the absence of overt Doppler abnormalities.