Single versus pairwise interpretation of cardiotochography, a comparative study from six Swedish delivery units.

•The proportion of correctly individually classified CTG's was 75% and the proportion of correctly pairwise classified CTG's was 80% (difference 5%, p = 0.12).•The baseline was high, 75% (95% CI: 72%–79%) individually correct classifications. This finding indicates a high standard of agreement in CTG classification in our study population, which was large and unselected, including both large and small delivery units.•Differences in proportion of correctly classified CTG recordings between the delivery units were observed, indicating a potential area of improvement in CTG interpretation.