Intra and interobserver variability of intrapartum transperineal ultrasound measurements with contraction and pushing

Abstract

The aim of this study was to evaluate the inter- and intraobserver correlation of the different intrapartum-transperineal-ultrasound-parameters(ITU) (angle of progression (AoP), progression-distance (PD), head-direction (HD), midline-angle (MLA) and head-perineum distance (HPD)) with contraction and pushing. We evaluated 28 nulliparous women at full dilatation under epidural analgesia. We performed a transperineal ultrasound evaluating AoP and PD in the longitudinal plane, and MLA and HPD in the transverse plane. Interclass correlation coefficients (ICC) with 95% CIs and Bland–Altman analysis were used to assess intra- and interobserver measurement’s repeatability. The ICC of the ITU for the same observer was adequate for all the parameters (p < .005) AoP 0.98 (95%CI, 0.96–0.99), PD 0.98 (95%CI, 0.97–0.99), MLA 0.99 (95%CI, 0.97–0.99), HPD 0.96 (95%CI, 0.88–0.99). The ICC of the ITU for interobserver was: AoP 0.93 (95%CI, 0.79–0.98), PD 0.92 (95%CI, 0.76–0.97), MLA 0.77 (95%CI, 0.42–0.92), HPD 0.47 (95%CI, −0.12–0.8). The HD had an interobserver correlation of 0.53 (95%CI, 0.1–0.9) (Kappa C). The mean difference of the AoP was 2.42°, of the PD 1 mm and 0.28° MLA (Bland–Altman test). ITU has an adequate intra- and interobserver correlation for its use with contraction and pushing under epidural analgesia.