Value of multimodal ultrasound assessment of placental dysfunction in gestational diabetes mellitus: a prospective study

Background: Gestational diabetes mellitus (GDM) induces progressive placental structural and functional abnormalities that are often undetectable by conventional ultrasound. Accurately assessing these changes is crucial for preventing adverse perinatal outcomes. This study aimed to evaluate the diagnostic value of multimodal ultrasound in assessing placental structural and functional alterations in pregnancies complicated by GDM, and to identify reliable sonographic biomarkers for evaluating placental abnormalities and clinical risk stratification. Methods: In this prospective study, 177 pregnant women undergoing routine antenatal care between 28 and 40 weeks of gestation were enrolled at Xiangyang No. 1 People’s Hospital from September 2022 to December 2024, including 82 patients with GDM and 95 healthy controls. Multimodal ultrasound was performed using spectral Doppler, three-dimensional (3D) power Doppler imaging, and shear wave elastography (SWE) to assess uterine artery (UtA), umbilical artery (UA), and middle cerebral artery (MCA) hemodynamics, placental perfusion indices [vascularization index (VI), flow index (FI), vascularization flow index (VFI)], and placental stiffness [central and marginal mean elasticity (Emean)]. Postnatal placental vascular casting was conducted for supporting qualitative evidence. Group comparisons used independent t-tests or Mann-Whitney U tests as appropriate. Univariate and multivariate logistic regression and receiver operating characteristic (ROC) analyses (Youden index) were performed. Results: Compared with controls, the GDM group had higher pre-pregnancy body mass index (BMI) (22.21±2.11 vs. 20.84±1.79 kg/m2) and glycated hemoglobin (HbA1c) (5.78%±0.87% vs. 5.17%±0.73%), both P<0.001. UtA indices were elevated in GDM [pulsatility index (PI): 0.86±0.29 vs. 0.76±0.24, P=0.013; resistance index (RI): 0.52±0.08 vs. 0.49±0.07, P=0.009; systolic/diastolic ratio (S/D): 2.44±0.45 vs. 2.30±0.40, P=0.029]. Placental perfusion indices were reduced (VI: 32.10±5.81 vs. 34.02±6.13, P=0.036; FI: 55.30±4.47 vs. 57.10±4.92, P=0.012; VFI: 11.47±2.72 vs. 13.91±3.03, P=0.013), whereas placental stiffness increased (central Emean: 6.17±0.19 vs. 6.04±0.16 kPa, P<0.001; marginal Emean: 8.10±0.20 vs. 8.02±0.18 kPa, P=0.006). In multivariate analysis, VFI [odds ratio (OR) =0.84, P=0.035], central Emean (OR =1.18, P=0.015), and marginal Emean (OR =1.22, P=0.012) were independently associated with GDM. Diagnostic performance was high for VFI [area under the curve (AUC) =0.849], central Emean (AUC =0.859), and marginal Emean (AUC =0.845); their combined model achieved AUC =0.898 with 80.00% sensitivity and 89.58% specificity (P<0.0001). Conclusions: Multimodal ultrasound is a valuable noninvasive tool for detecting placental functional and structural abnormalities in GDM. Parameters such as VFI and placental elasticity may serve as effective biomarkers for monitoring GDM-related placental changes and prenatal management. Integration of these imaging modalities can enhance the precision of risk assessment and support individualized perinatal care.