Objective: To determine accuracy of clinicians in estimating cervical dilatation during the active phase of labour and how this is affected by clinician experience and obstetric factors.
Design: Prospective, cross-sectional, comparative study.
Setting: Chris Hani Baragwanath Hospital labour ward, Johannesburg, South Africa.
Population: Women at term in the active phase of labour, with vertex presentations and live fetuses.
Methods: The researcher performed cervical assessment immediately after the clinician on duty. The researcher and clinician were unaware of each other's findings. The researcher, used as the standard, was an experienced obstetric consultant, and the clinicians were hospital consultants and registrars at various levels of training. Accuracy was defined as agreement of the clinician's cervical dilatation estimate with that of the researcher. Multivariate logistic regression analysis was carried out to determine independent predictors of inaccuracy.
Main outcome measure: Agreement in estimation of cervical dilatation between the researcher and the clinicians.
Results: Examinations were performed on 508 women. The researcher and clinicians agreed on the dilatation in 250 instances (49.2%) and differed by 2 cm or more in 56 (11.0%) (kappa = 0.40, 95% CI 0.34-0.45). Accuracy was greater at low (3-4 cm) and high (8-10 cm) dilatations. Reduced accuracy was associated with decreasing clinician experience and with lower stations of fetal head.
Conclusion: This is the first study to investigate accuracy of cervical assessment in parturient women. Results were similar to those found in studies that used models, with about 90% of estimations accurate to within 1 cm.