Intrapartum sonography to determine fetal occipital position: Interobserver agreement

Abstract

Objective: To investigate the interobserver agreement on the intrapartum ultrasonographic definition of the fetal occipital position. Methods: In 60 singleton pregnancies in labor at term the fetal occipital position was determined by transabdominal ultrasound by two appropriately trained sonographers who were not aware of each other's findings. The Bland-Altman plot was performed and the 95% limits of agreement were calculated. Logistic regression analysis was used to investigate the association between complete agreement in the fetal occipital position between the two observers and maternal and labor characteristics. Results: The two observers had complete agreement on the fetal occipital position in 22/60 (36.7%) cases and disagreement by 15° and 30° in 31 (51.7%) and seven (11.6%) cases, respectively. The mean of the differences between the two observers was 0.25° and the 95% limits of agreement were -28.9° (-32.2° to -25.6°) to 29.4° (26.1° to 32.7°). There were no significant associations between complete agreement and maternal and labor characteristics. Conclusion: The interobserver agreement on sonographically determined fetal occipital position during labor is within 15° in nearly 90% of cases and within 30° in all cases. Copyright ©2004 ISUOG. Published by John Wiley & Sons, Ltd.