Fetal Interventricular Septum Volume Evaluated by Four-Dimensional Ultrasound Using Spatiotemporal Image Correlation (STIC) and Virtual Organ Computer-Aided Analysis (VOCAL) in Fetuses from Gestational Diabetes Mellitus Pregnant Women Compared to Fetuses from Healthy Pregnant Women.

Purpose: To evaluate fetal interventricular septum (IVS) volume in pregnant women with gestational diabetes mellitus (GDM) and compare it with that of healthy pregnant women using 4D ultrasound with spatiotemporal image correlation (STIC) and virtual organ computer-aided analysis (VOCAL) methods. Patients and Methods: This prospective cross-sectional study was conducted at Bhumibol Adulyadej Hospital, Royal Thai Airforce, Bangkok, Thailand, from November 2024 to March 2025. Pregnant women with a gestational age (GA) between 29 and 34 weeks were enrolled and divided into two groups: GDM and healthy controls. Fetal IVS volume was measured using 4D ultrasonography with STIC and VOCAL. Maternal, fetal, and demographic data were collected and analyzed. Results: A total of 111 participants were included: 63 in the GDM group and 48 in the control group. The GDM group was significantly older (33.0 vs 27.9 years) and had a higher BMI (31.1 vs 26.8 kg/m2). Mean fetal IVS volume was significantly greater in the GDM group (347.1 mm3 vs 221.5 mm3). Adverse neonatal outcomes were comparable. The cut-off fetal IVS volume for predicting neonatal hyperbilirubinemia (HBB) and respiratory distress syndrome (RDS) was 419.8 mm3. Sensitivity for predicting HBB and RDS was 55.0 and 56.0%, with negative predictive values of 94.0 and 95.2%, respectively. Conclusion: Fetal IVS volume was significantly higher in GDM pregnancies. A cut-off value of 419.8 mm3 may be useful in predicting HBB and RDS risk, with high negative predictive value, suggesting its potential as a screening tool during the early third trimester.