Agreement between digital vaginal examination and intrapartum ultrasound for labour monitoring.

Sonographic approach for labour monitoring was introduced in order to improve the shortcomings of digital vaginal examination (DVE). This was a prospective study. We aimed to investigate the agreement between transperineal ultrasound (TPUS) measurements and DVE during first and second stages of labour. Patients in the first stage of labour were included. Cervical length (CL), cervical dilation (CD), cervical position (CP), foetal head descent (FHD) and foetal head rotation (FHR) were assessed by both DVE and TPUS. Agreement between two methods was examined. Eighty-five patients were included. One hundred and eighty-three paired TPUS and DVE assessments were performed. Satisfactory agreement between both methods was obtained regarding CL: systematic bias= -0.05 cm (95%CI, -0.13; 0.03),  = 0.7, <.0001; CD: systematic bias = 0.07 cm (95%CI, -0.08 to 0.22),  = 0.93, <.0001 and FHD: systematic bias = 0.83 cm (95%CI, 0.685-0.977),  = 0.55, <.0001. There was a low correlation for the assessment of CP (kappa = 0.24) and FHR (kappa = 0.06). DVE was inefficient in determining FHR especially during latent phase with failure and error rates of 86% and 36%, respectively. A conceptual sonopartogram covering the hole childbirth process is presented based on reliable ultrasound measurements.Impact Statement Digital vaginal examination (DVE) is used worldwide for labour monitoring. However, it is far from perfect. Some investigators have raised concerns about the value of the Bishop score because it is a subjective measure with great intra- and inter-observer variability, affected by a physician's clinical experience. Moreover, this method is intrusive, uncomfortable and may increase the risk of infection. The sonographic approach for labour monitoring was introduced in order to improve the shortcomings of DVE. Multiple studies focussed on the reliability of the sonographic method in assessing each parameter during labour. Hassan et al. were the first to determine whether it is feasible to perform assessment in the first stage of labour based only on US, and to describe a method of recording these observations: the 'sonopartogram'. The outcomes concluded that sonographic approach was at least as accurate as the clinical examination. Moreover, a conceptual sonopartogram covering the hole childbirth process is presented based on reliable ultrasound measurements. Clinical relevance of this sonopartogram should be evaluated in further studies.