Prenatal evaluation, diagnosis and management of fetal corpus callosal abnormalities: international Delphi consensus

The corpus callosum (CC) is an interhemispheric structure that facilitates communication between the two cerebral hemispheres. Anomalies of the CC are frequent and associated with a wide spectrum of altered neurodevelopmental outcomes. However, variability in diagnostic criteria and the lack of standardized management strategies create challenges for clinicians and anxiety for expectant parents. This study aimed to establish an international consensus on the prenatal evaluation, diagnosis and management of fetal CC abnormalities using a structured Delphi methodology.

A three-round Delphi process was conducted among an international panel of fetal medicine experts, identified based on clinical expertise and publication history. Structured statements regarding CC evaluation, diagnosis and management were developed through expert input and a scoping literature review. The statements were iteratively refined and scored by the panel using a five-point Likert scale in the first two rounds. During the final round, consensus was defined as > 70% agreement among participants.

Fifty-five experts participated in the first round, with 43 (78.2%) experts completing the entire process. Key consensus findings included the incorporation of obtaining a sagittal view of the brain in routine ultrasound screening (72.4% agreement), without requiring measurement even when an anomaly is suspected (93.1% agreement), but instead with recommended referral to a specialist (100% agreement). For diagnostic ultrasound, three-dimensional ultrasound imaging (72.4% agreement) and transvaginal ultrasound evaluation (82.8% agreement) were recommended, with targeted measurements of CC length in the case of a subjective impression of abnormal size (82.8% agreement). However, it was agreed that there is no consensus on the reference chart or cut-off values to be used for defining abnormal CC length (86.2% and 89.3% agreement, respectively). In terms of management, it was agreed that both an invasive genetic workup and magnetic resonance imaging (MRI) should be offered in case of suspected dysgenesis of the CC (100% agreement). MRI should be performed if the CC appears to be too short (100% agreement), thin (100% agreement) or thick (92.0% agreement). In the case of an isolated CC with heterogeneous echogenicity, an infectious workup is recommended (86.2% agreement).

This study provides a structured framework for the evaluation and management of fetal CC abnormalities. By standardizing approaches to imaging and management, the recommendations aim to improve diagnostic accuracy, optimize patient outcomes and reduce unnecessary interventions. Further prospective studies are needed to validate these recommendations and assess their impact on clinical care. © 2025 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.