Intrapartum ultrasound assessment of cervical dilatation and its value in detecting active labor

Abstract

IntroductionWe aimed to examine the agreement between ultrasound and digital vaginal examination in assessing cervical dilatation in an African population and to assess the value of ultrasound in detecting active labor.MethodA cross-sectional study was conducted in a teaching hospital in Ghana between April and September of 2016. Anterior–posterior and transverse diameters of cervical dilatation were measured with ultrasound and the mean value was compared with digital vaginal examination in 195 women in labor. Agreement between methods was examined with correlation coefficients and with Bland–Altman plots. Active labor was defined when cervix was dilated ≥ 4 cm with vaginal examinations. ROC curve analysis was conducted on the diagnostic performance of ultrasound in detecting active labor.ResultsData were analyzed in 175 out of 195 (90%) cases where ultrasound could clearly visualize the cervix. The remaining 20 cases were all determined by digital vaginal examination as advanced cervical dilatation (≥ 8 cm), advanced head station (≥ + 2), and with ruptured membranes. The Pearson correlation coefficient (r) was 0.78 (95% CI 0.72–0.83) and the intra-class correlation coefficient was 0.76 (95% CI 0.69–0.81). Bland–Altman analysis obtained a mean difference of − 0.03 cm (95% CI − 0.18 to 0.12) with zero included in the CI intervals, indicating no significant difference between methods. Limits of agreement were from − 2.01 to 1.95 cm. Ultrasound predicted active labor with 0.87 (95% CI 0.75–0.99) as the area under the ROC curve.ConclusionUltrasound measurements showed good agreement with digital vaginal examinations in assessing cervical dilatation during labor and ultrasound may be used to detect active labor.

Feasibility, Reliability, and Agreement of Transperineal Ultrasound Measurement: Results from a Longitudinal Cohort Study

“…The cur-rent report has extended the aforementioned observations supporting the use of TPU along with vaginal examination for the monitoring of labor progress. To date, this is the largest prospective longitudinal study with paired assessment of vaginal examination and TPU, and these findings are in agreement with previous reports [36][37][38][39][40]. AOP appears to have a better correlation with fetal head station determined by vaginal examination than HPD, and this might be due to the clear anatomical landmarks that define its measurement.…”

“…Prior to implementation of the TPU assessment of labor progress into clinical setting, knowledge of its feasibility, reliability, and agreement is required. Previous studies have determined the reliability and/or agreement between fetal head descent and cervical dilatation determined by vaginal examination and TPU [36][37][38][39][40]. However, these studies have a small number of paired measurements.…”

Acceptability of intrapartum ultrasound by mothers in an African population

“…The study involved postpartum women who had undergone both ultrasound and digital VE during the index delivery in order for the progress of labour to be assessed. Detailed descriptions of the ultrasound and digital VE have been provided elsewhere [10]. In brief, vaginal examination was performed by an experienced clinician and in accordance with the standard protocol for the procedure in the facility.…”

“…A transperineal ultrasound was performed immediately after the transabdominal scan by asking the mother to flex her legs with knees apart. Transperineal ultrasound examination was performed using the same transducer to determine cervical dilatation and other parameters associated with the determination of head station [9,10].…”

“…A comprehensive guide to using ultrasound in labour has been published by the International Society for Ultrasound in Obstetrics and Gynecology (ISOUG) [8]. For the first time, ultrasound in labour has also been reported as highly comparable to digital VE in the measurement of cervical dilatation, fetal head station and engagement in a black African population [9,10].…”