Agreement between two- and three-dimensional transperineal ultrasound methods in assessing fetal head descent in the first stage of labor.

To study intraobserver repeatability and intermethod agreement between two- (2D) and three-dimensional (3D) transperineal ultrasound methods in assessing fetal head descent during the first stage of labor. Fetal head descent was measured with transperineal ultrasound as the fetal head-perineum distance and the angle of progression in 106 primiparous women with prolonged first stage of labor. A single obstetrician performed all the scans, and another obstetrician analyzed the acquired 2D images and 3D volumes, blinded to clinical assessments and labor outcome. Intraobserver repeatability and intermethod agreement between 2D and 3D methods were analyzed. The repeatability coefficient was ± 4.1 mm in 2D acquisitions and ± 1.7 mm in 3D acquisitions of fetal head-perineum distance. The intraclass correlation coefficients (ICC) were 0.94 for 2D and 0.99 for 3D measurements. The angle of progression repeatability coefficients were ± 6.7° using 2D and ± 5.7° using 3D ultrasound and ICCs were 0.91 and 0.94, respectively. The intermethod ICC for fetal head-perineum distance in 2D vs 3D acquisitions was 0.95 and for angle of progression it was 0.93; the intermethod 95% limits of agreement were - 5.8 mm to + 7.2 mm and - 8.9° to + 13.7°, respectively. Cohen's kappa for 2D vs 3D acquisitions was 0.85 using 40 mm as a cut-off level for fetal head-perineum distance and 0.79 using 110° as cut-off level for angle of progression. For one ultrasound operator the intraobserver repeatability and agreement between 2D and 3D ultrasound methods in prolonged first stage of labor were good. Given that 2D methods are simpler to learn and can be analyzed quickly online, 2D equipment might therefore be preferred in the labor room.

Torkildsen EA ，Salvesen KÅ ，Eggebø TM 《-》

Prediction of delivery mode with transperineal ultrasound in women with prolonged first stage of labor.

To investigate if fetal head-perineum distance and angle of progression measured with two-dimensional (2D) and three-dimensional (3D) transperineal ultrasound could predict outcome of labor in primiparous women with prolonged first stage of labor. This was a prospective observational study of 110 primiparous women with singleton cephalic presentation at term diagnosed with prolonged first stage of labor. Digital assessment of fetal station was related to the ischial spine. Fetal head descent was measured with transperineal ultrasound as the shortest distance from the fetal head to the perineum, and the angle between the pubic symphysis and the fetal head. Receiver-operating characteristics (ROC) curves were constructed and 2D and 3D data acquisitions were compared. The stored 3D volumes were assessed by an examiner blinded to all other data. Vaginal delivery vs. Cesarean section was the primary outcome. Cesarean section was performed in 25% of the women. Areas under the ROC curves for prediction of vaginal delivery were 81% (95% confidence interval (CI), 71-91%) (P < 0.01) and 76% (95% CI, 66-87%) (P < 0.01) for fetal head-perineum distance and angle of progression, respectively, as measured by 2D ultrasound and 66% (95% CI, 54-79%) for digital assessment of fetal station (P = 0.01). In 50% of women fetal head-perineum distance was ≤ 40 mm and 93% (95% CI, 83-97%) of them delivered vaginally vs. 18% (95% CI, 5-48%) with distance > 50 mm. In 48% of women the angle of progression was ≥ 110° and 87% (95% CI, 75-93%) of them delivered vaginally vs. 38% (95% CI, 21-57%) with angle < 100°. Results from 2D and 3D acquisitions were similar. Fetal head-perineum distance and angle of progression measured with 2D or 3D ultrasound can predict labor outcome, with similar predictive values for the two techniques.

Torkildsen EA ，Salvesen KÅ ，Eggebø TM 《-》

Agreement between two- and three-dimensional transperineal ultrasound methods for assessment of fetal head-symphysis distance in active labor.

To assess the intermethod agreement between two-dimensional (2D) and three-dimensional (3D) transperineal ultrasound methods in measuring a new index of fetal head station (the fetal head-symphysis distance (HSD)) in active labor, and to assess potential factors that may affect their agreement. HSD was measured by transperineal ultrasound in 86 women in active labor, once using a 2D and once using a 3D technique. 2D images were acquired first in 43 cases and 3D images were acquired first in the other 43 women. Intermethod agreement between 2D and 3D methods was analyzed by means of intraclass correlation coefficient (ICC) and Bland-Altman analysis. In addition, potential factors affecting the intermethod reproducibility were investigated including fetal occiput position, order of acquisition, fetal head station, stage of labor, maternal body mass index and use of epidural analgesia, using the ANOVA test to check for systematic bias and Levene's test for homoscedasticity. Good agreement was demonstrated between 2D and 3D measurements of HSD (ICC, 0.949 (95% CI, 0.914-0.984)). No evidence of systematic difference was shown between the two methods (average difference ± SD = 0.03 ± 2.29 mm; P = 0.888). The only factor that had a significant effect on systematic difference between 2D and 3D methods was order of acquisition (P = 0.042); the first observation was higher regardless of the method used. Fetal head station had a significant effect on the homogeneity between the two methods (P = 0.004) with a better 2D-3D agreement obtained at lower head stations (SD of differences: 1.63 vs 2.59 mm). There is very good agreement between 2D and 3D methods of assessing HSD. Agreement is better in lower fetal head stations.

Youssef A ，Bellussi F ，Montaguti E ，Maroni E ，Salsi G ，Morselli-Labate AM ，Paccapelo A ，Rizzo N ，Pilu G ，Ghi T ... -  《-》

What is the most reliable ultrasound parameter for assessment of fetal head descent?

The aims of this study were, first, to establish the agreement between digital and ultrasound assessment of occipital position and, second, to evaluate the repeatability of the measurements of head direction, angle of the middle line, progression distance and angle of progression in women in the second stage of labor. Digital examination and then transabdominal ultrasound examination was performed on 50 women in the second stage of labor to determine the fetal occipital position. We also obtained three-dimensional (3D) blocks of the fetal head by transperineal sonography, and two experts in 3D ultrasound measured head direction, angle of the middle line, progression distance and angle of progression. Intraclass correlation coefficients with 95% CIs, and Bland-Altman analysis, were used to evaluate intraobserver and interobserver repeatability of measurements. The fetal head position, determined by ultrasound examination, was occiput anterior in 33 (66%) cases and occiput lateral in 17 (34%) cases. Vaginal digital examination failed to identify the correct fetal head position by more than 45° in 33 (66%) cases. All four 3D ultrasound measurements were reproducible but the progression angle had the highest intraclass correlation coefficient for the same observer (0.94; 95% CI, 0.90-0.97) and for two different operators (0.84; 95% CI, 0.73-0.91). The progression angle was also the measurement for which smaller limits of agreement (LOA) were found in the Bland-Altman test, performed to calculate the intraobserver (bias 0.9; LOA, - 9.2 to 11.1%) and interobserver (bias 1.5; LOA, - 15.4 to 18.3%) variability. Digital pelvic examination for determining the fetal head position during labor is not accurate. The most reproducible of the 3D measurements for progression of the fetal head in labor is the progression angle.

Molina FS ，Terra R ，Carrillo MP ，Puertas A ，Nicolaides KH ... -  《-》

Measurement of fetal head descent using the 'angle of progression' on transperineal ultrasound imaging is reliable regardless of fetal head station or ultrasound expertise.

Dückelmann AM ，Bamberg C ，Michaelis SA ，Lange J ，Nonnenmacher A ，Dudenhausen JW ，Kalache KD ... -  《-》