Ultrasound examination during labor - a prospective pilot comparative study of clinical and ultrasonographic accuracy.

Abstract

Objective: The aim of this pilot study was to evaluate and compare the diagnostic accuracy of digital vaginal examination versus intrapartum ultrasound (IUS) during the first and second stages of labor in women with cephalic presentation.

Materials and methods: This prospective comparative study was conducted at the Department of Gynecology and Obstetrics, L. Pasteur University Hospital in Košice. The cohort included parturients (regardless of parity) with regular uterine contractions, cephalic presentation, and ruptured membranes. To ensure high data quality, all ultrasound examinations were performed by senior obstetricians with at least 8 years of clinical experience. Examining obstetricians were blinded to each other's findings. The assessment focused on fetal position, head position, head station, and progression during labor. IUS included a transabdominal approach (head position) and a transperineal approach, measuring head-perineum distance and angle of progression. In cases of discrepancy, the ultrasound finding was considered the reference standard.

Results: A total of 47 patients were included. Agreement between IUS and VE across all parameters was observed in 27 cases (57%). Discrepancies were noted in 20 patients (43%), with the most frequent errors occurring in the assessment of fetal head position. The statistical superiority of ultrasound over digital examination was highly significant (P < 0.0001). Presence of a caput succedaneum was a major confounding factor, which was present in 45% of non-correlated cases. The caesarean section rate in the cohort was 21% (N = 10).

Conclusion: While vaginal examination remains the global gold standard in routine obstetrics, it is inherently subjective and prone to inter-observer variability. Our findings suggest that intrapartum ultrasound provides a more objective, accurate, and reproducible assessment. Incorporating IUS into labor management may reduce the need for frequent digital examinations, potentially lowering the risk of chorioamnionitis and enhancing patient comfort while optimizing clinical decision-making.