Intrapartum Sonography: Redefining Evaluation of Fetal Head Position

Prolonged or arrested labor remains one of the most challenging intrapartum scenarios faced by obstetric clinicians. Among the leading contributors are fetalmalpresentation, malposition, and asynclitism—conditions that historically depend on subjective and often inconsistent vaginal examination for diagnosis. As labor management evolves, so too must our diagnostic strategies. In this context, intrapartum sonography has emerged as a pivotal tool, offering objectivity, reproducibility, and improved accuracy in assessing the fetal head position and attitude.

Over the past decade, robust evidence has demonstrated that ultrasound surpasses clinical examination in identifying cephalic malposition. Several international guidelines now recommend using sonography—particularly before instrumental delivery—to confirm fetal occiput position. The technique is not only more precise but also feasible: basic assessment of occiput position can be mastered even by clinicians with foundational ultrasound skills. A simple transabdominal scan in axial and sagittal planes, with the probe placed suprapubically, can reliably identify key anatomical landmarks such as the orbits, midline structures, cerebellum, and cervical spine.

However, more complex assessments—such as diagnosing cephalic malpresentation (sinciput, brow, or face) or detecting asynclitism—require greater expertise. Recent work has introduced objective sonographic parameters like the occiput–spine angle and chin–chest angle, offering quantifiable metrics to evaluate fetal head deflexion. Similarly, the diagnosis of asynclitism gains clarity through combined transabdominal and transperineal views, where findings such as the “squint sign” or displaced sagittal suture provide definitive clues.

The clinical implications are significant. Accurate intrapartum diagnosis informs timely decision-making, improves anticipation of labor progression, and may help stratify women at risk of operative birth or labor arrest. For those experiencing a protracted active phase, detailed sonographic evaluation may help identify the underlying cause—guiding individualized and safer management strategies.

As obstetric practice continues its shift toward precision-based care, intrapartum sonography stands as an essential companion. It enhances both the safety and quality of labor management while reducing reliance on subjective clinical impressions. Integrating these techniques into routine practice—and ensuring appropriate training pathways—will be key to optimizing maternal and neonatal outcomes in the years ahead.