Second‐trimester fetal cardiac remodeling in gestational diabetes: Discriminative value of cardiac morphometry for gestational diabetes and adverse perinatal outcomes

Objective This study evaluates second‐trimester fetal cardiac morphometric parameters in gestational diabetes mellitus (GDM) pregnancies compared with healthy controls, assesses their discriminative ability for GDM and composite adverse perinatal outcome (CAPO), and identifies morphometric parameters associated with CAPO. Methods A total of 180 singleton pregnancies were included: 90 women with GDM (30 insulin‐treated and 60 diet‐controlled) and 90 gestational‐age‐matched controls. Fetal echocardiographic assessments were performed at 20–22 gestational weeks. Results Gestational diabetes mellitus fetuses exhibited a significantly lower right ventricular sphericity index, greater interventricular septal (IVS) thickness, a lower cardiac sphericity index, and a greater cardiac transverse diameter compared with controls. Receiver operating characteristic analysis identified the right ventricular sphericity index as the best discriminator for GDM (area under the curve [AUC] 0.808; cut‐off ≤1.65; sensitivity 74.4%, specificity 77.8%), while IVS thickness exhibited the highest discriminative performance for CAPO (AUC 0.810; cut‐off >2.09 mm; sensitivity 84.6%, specificity 76.2%). In multivariable analysis, right ventricular sphericity index below Q1 (adjusted odds ratio [OR] 7.71; P < 0.001), cardiac sphericity index below Q1 (adjusted OR 3.9; P = 0.004), and pre‐pregnancy body mass index >30 kg/m 2 (adjusted OR 5.3; P < 0.001) were independent discriminating factors of GDM. IVS thickness above Q3 (>2.18 mm) was identified as an independent discriminating factor of CAPO (adjusted OR 3.41; P = 0.001). Conclusion The right ventricular sphericity index and IVS thickness are the most clinically useful parameters for discriminator GDM and CAPO, respectively. These findings are hypothesis‐generating and require prospective, multicenter validation before integration into clinical practice. Targeted second‐trimester cardiac morphometric assessment might complement existing GDM monitoring strategies in future research settings.