Quantification of fetal head direction and descent

Intrapartum ultrasound and mother acceptance: A study with informed consent and questionnaire

Introduction

Intrapartum ultrasound (IU) is used in the delivery ward; even if IU monitors the labouring women, it could be perceived as a discomfort and even as an" obstetric violence", because it is a young technique, not often well "accepted". A group of clinicians aimed at obtain an informed consent from patients, prior to perform a translabial ultrasound (TU). The aim of this study was to evaluate the acceptance of both translabial and transabdominal IU.

Methods

In this study, performed at the University Hospital of Bari (Unit of Obstetrics and Gynecology), were enrolled 103 patients in the first or second stage of labor in singleton cephalic presentation. A statistical frequency and an association analysis were performed. As a significant result, we consider the peace of mind/satisfaction and the" obstetric violence". IU was performed both transabdominal and translabial to determine the presentation, head positions, angle of progression and head perineum distance. During the first and second stage of labor, the ASIUG questionnaires (Apulia study intrapartum ultrasonography group) were administered.

Results

74 (71, 84%) patients underwent IU and 29 had a vaginal examination (28, 15%). Significant less "violence" has been experienced with a IU (73 out 74/98, 65%) and only one person (1 /1, 35%) recorded that. On the contrary, 10 patients (10/29) perceived that "violence" (34, 48%) while 19 (65, 52%) did not respond on a similar way, after a vaginal examination (VE). More patients felt satisfaction (71 out 74/95, 95%) with the use of IU and only 3 (3/4, 05%) felt unease. A different picture was evident in the vaginal examination group. Only 17 patients (17 out 29/58, 62%) felt comfort while 12 (41, 38%) felt unease.

Conclusions

In our study, IU use is well accepted by most of patients, because it could reassure women about their fetal condition. Moreover, they can see the fetus on the screen, while the obstetrician is performing the US and this is important for a visual feedback, in comparison with the classical VE.

Transperineal ultrasound assessment of maternal pelvic floor at term and fetal head engagement

OBJECTIVES

To evaluate the association between pelvic floor dimensions in nulliparous women at term and fetal head engagement, as assessed by transperineal ultrasound.

METHODS

This was a prospective observational study of nulliparous women at term. Before the onset of labor, transperineal ultrasound was used to measure the anteroposterior diameter (APD) of the levator hiatus and the angle of progression (AoP) at rest, on maximum pelvic floor muscle contraction and on maximum Valsalva maneuver (before and after visual feedback). We assessed the correlation between pelvic floor static and dynamic dimensions (levator hiatal APD and levator ani muscle coactivation) and AoP, which is an objective index of fetal head engagement.

RESULTS

In total, 282 women were included in the analysis. Among these, 211 (74.8%) women had a vaginal delivery while 71 (25.2%) had a Cesarean delivery. AoP was narrower in the Cesarean-delivery group at rest, on maximum pelvic floor muscle contraction and on maximum Valsalva, whereas no differences in levator hiatal APD were found between the two groups. We found a negative correlation between levator hiatal APD at rest, on maximum pelvic floor muscle contraction and on maximum Valsalva and the duration of the second stage of labor. There was a positive correlation between AoP and levator hiatal APD on maximum Valsalva maneuver after visual feedback (r = 0.15, P = 0.01). Women with levator ani muscle contraction on Valsalva maneuver (i.e. coactivation), both pre and post visual feedback, had a narrower AoP at rest and on maximum Valsalva. After visual feedback, women with levator ani muscle coactivation had a longer second stage of labor than did those without (80.8 ± 61.4 min vs 62.9 ± 43.4 min (P = 0.04)).

CONCLUSIONS

Smaller pelvic floor dimensions and levator ani muscle coactivation are associated with higher fetal head station and with a longer second stage of labor in nulliparous women at term. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Agreement between two 3D ultrasound techniques for the assessment of the subpubic arch angle

OBJECTIVES

To assess the reliability of a new three-dimensional (3D) ultrasound technique for the measurement of the subpubic arch angle (SPA) and the agreement between two contrast-enhancing 3D ultrasound techniques.

METHODS

We acquired two static 3D transperineal volumes from 72 nulliparous women using two ultrasound machines equipped with two different 3D contrast enhancement and linear reconstruction softwares: 1. Oblique View Extended Imaging with HD-Volume Imaging (OVIX-HDVI™), Samsung; 2. Omniview with Volume Contrast Imaging (Omniview-VCI™), GE Healthcare. An operator measured SPA once by OVIX-HDVI, and twice by Omniview-VCI, while another operator measured SPA once by Omniview-VCI. We evaluated intra- and inter-observer reproducibility of Omniview-VCI and intermethod agreement. Reproducibility and intermethod agreement were studied by means of intraclass correlation coefficient (ICC) and Bland-Altman method.

RESULTS

Omniview-VCI SPA measurements showed excellent intraobserver and interobserver reproducibility (ICC 0.970; 95% C.I. 0.952 to 0.981, 0.932; 95% C.I. 0.893 to 0.957, respectively). Furthermore, Omniview VCI SPA measurements demonstrated excellent agreement with those performed by OVIX-HDVI technique (ICC 0.943; 95 C.I. 0.911 to 0.964). No systematic difference was found in any of the reliability studies.

CONCLUSIONS

OmniView-VCI is a reliable method for SPA assessment. Both OmniView-VCI and OVIX-HDVI can be used interchangeably for SPA measurement.

Comparison between ultrasound parameters and clinical examination to assess fetal head station in labor

OBJECTIVE

Several ultrasound parameters, including intrapartum transperineal ultrasound (ITU) head station, angle of progression (AOP), head-perineum distance (HPD) and head-symphysis distance (HSD), have been suggested to assess fetal head station during labor. The aim of this study was to analyze the relationship between these ultrasound parameters and to compare them with digital palpation.

METHODS

We analyzed 106 stored volume dataset pairs that had been acquired at Stavanger University Hospital, Norway, from nulliparous women at term with prolonged first stage of labor. The volumes were acquired using a three-dimensional transducer applied between the labia majora in a mid-sagittal plane and perineally in a transverse plane. Digitally palpated head station and cervical dilatation were also noted. The results were compared using regression and correlation coefficients.

RESULTS

There were good correlations between ITU head station and HPD (r = 0.71), between ITU head station and HSD (r = 0.74) and between HSD and HPD (r = 0.75). Palpated head station showed only moderate correlation with ITU head station (r = 0.52). Cervical dilatation showed a weak correlation with ITU head station (r = 0.30).

CONCLUSION

The ultrasound parameters showed a high degree of correlation with each other, but only moderate correlation to vaginally palpated fetal head station.