Department of Obstetrics and Gynecology, University of Bologna, Bologna, Italy.
Ultrasound Obstet Gynecol. 2009 Mar;33(3):331-6. doi: 10.1002/uog.6313.
To investigate the ability of intrapartum translabial sonography to diagnose fetal station in the second stage of labor.
Patients with uncomplicated pregnancies at term gestation with fetuses in vertex presentation in the second stage of labor underwent serial translabial sonography and digital examinations. In a sagittal section of the maternal pelvis, the direction of the head was noted and categorized as downward, horizontal or upward. By rotating the transducer in the transverse plane the cerebral midline echo was also visualized and the rotation of the head was noted. Clinical and ultrasound data were compared using Somer's d-test.
Sixty patients underwent a total of 168 clinical and sonographic examinations. When on the sonogram the fetal head was directed downward, the station assessed clinically was most frequently <or= + 1 cm from the ischial spines (44/57 (77.2%) cases); when the direction was horizontal, the station was most frequently <or= + 2 cm (53/59 (89.8%) cases); when the fetal head was directed upward, the station was usually >or= + 3 cm (46/52 (88.5%) cases). Failure to visualize the cerebral midline or a rotation >or= 45 degrees were associated with a station of + 2 cm or less in 98/103 (95.1%) examinations. Conversely, a rotation of < 45 degrees was associated with a station of + 3 cm or more in 45/65 (69.2%) examinations. All comparisons between clinical and sonographic findings demonstrated a statistically significant relationship (P < 0.0001). The probability of a station + 3 cm or more was particularly high when an upward direction of the head was seen in combination with a rotation of < 45 degrees (40/42 (95.2%) examinations). The interobserver variability (Cohen's kappa 0.795 and 0.727 for station and rotation, respectively; P < 0.001) and intraobserver variability (0.845 for both station and rotation, P < 0.001) suggested good reproducibility of the method.
Translabial sonography allows a diagnosis of fetal station with an accuracy comparable to that of digital examination and may provide useful information for diagnosing obstructed labor in the second stage as well as assisting in the choice of instrumental delivery.
探讨产时经阴道超声在第二产程中诊断胎方位的能力。
对足月、头位、第二产程的孕妇行连续经阴道超声和数字检查。在母体骨盆矢状切面中，记录胎头的方向并分为向下、水平或向上。通过在横切面旋转探头，也可以观察到大脑中线回声，并记录胎头的旋转。使用 Somer's d 检验比较临床和超声数据。
60 例患者共进行了 168 次临床和超声检查。当在超声上胎头向下时，临床评估的胎方位最常位于坐骨棘下 1cm 以内（44/57 [77.2%]例）；当方向为水平时，胎方位最常位于坐骨棘下 2cm 以内（53/59 [89.8%]例）；当胎头向上时，胎方位通常位于坐骨棘上 3cm 以内（46/52 [88.5%]例）。无法观察到大脑中线或旋转 > 45 度与 103 次检查中的 98/103（95.1%）胎方位为 2cm 或以下有关。相反，45 次检查中 < 45 度的旋转与 65 次检查中的 45/65（69.2%）胎方位为 3cm 或以上有关。所有临床与超声检查结果的比较均显示具有统计学意义（P < 0.0001）。当胎头向上且旋转 < 45 度时，胎方位为 3cm 或以上的可能性特别高（42 次检查中的 40/42 [95.2%]）。观察者间的可重复性（胎方位和旋转的 Cohen's kappa 分别为 0.795 和 0.727；P < 0.001）和观察者内的可重复性（胎方位和旋转的 0.845；均 P < 0.001）均表明该方法具有良好的可重复性。
经阴道超声可准确诊断胎方位，与数字检查相当，可为诊断第二产程中梗阻性分娩提供有用信息，并有助于选择器械分娩。
