Comparative Analysis of Fetal Brain Structures in Gestational Diabetes versus Normal Pregnancy: A Prospective Cohort Study
Kamonchanok Choosak, MD¹, Podjanee Phadungkiatwattana, MD¹
Affiliation : ¹ Maternal and Fetal Medicine Unit, Department of Obstetrics and Gynecology, Rajavithi Hospital, Bangkok, Thailand
Objective: To evaluate whether gestational diabetes mellitus (GDM) affects fetal brain structures, including the cavum septum pellucidum (CSP), posterior lateral ventricle (PLV), cisterna magna (CM), cerebellum, and thalamus by prenatal ultrasound, and to examine the association between maternal hemoglobin A1c (HbA1c) levels and these structures.
Materials and Methods: The present study was a prospective cohort study that included 100 singleton pregnancies, which included 50 GDM and 50 non-GDM, at Rajavithi Hospital, Bangkok, Thailand. All participants underwent HbA1c testing and prenatal ultrasound between 29 and 32 weeks of gestation to assess CSP, PLV, CM, cerebellum, and thalamus. Perinatal and neonatal outcomes were subsequently recorded.
Results: Baseline demographic characteristics were similar between groups except for higher mean (SD) HbA1c levels in the GDM group at 5.04% (0.44) versus 4.83% (0.40) (p=0.018). Among brain structures, only the mean (SD) PLV was significantly larger in the GDM group compared with controls at 5.45 mm (1.25) versus 4.69 mm (1.01) (p=0.001). HbA1c levels were positively correlated with the PLV (r=0.258, p=0.009) and CM (r=0.240, p=0.016). Receiver operating characteristic (ROC) curve analysis revealed that the PLV exhibited fair discriminative ability in identifying pregnancies with GDM (AUC 0.697, p=0.001). Using PLV as a predictor of GDM, a cutoff of 4.6 mm yielded a sensitivity of 74% and specificity of 60%, while a cutoff of 5.0 mm showed lower sensitivity (60%) but higher specificity (74%). Perinatal and neonatal outcomes were similar between groups.
Conclusion: Fetuses of mothers with GDM demonstrated significantly larger PLVs, which correlated with maternal HbA1c levels and showed fair discriminative ability for GDM. These findings suggest that maternal glycemic status may influence fetal development of the lateral ventricle and that prenatal ultrasound could serve as a valuable tool for early detection.
Received 21 October 2025 | Revised 16 December 2025 | Accepted 17 December 2025
DOI: 10.35755/jmedassocthai.2026.2.03752
Keywords : Gestational diabetes mellitus; Fetal brain structures; Cavum septum pellucidum; Lateral ventricle; Cisterna magna
