Ultrasound in labor: clinical practice guideline and recommendation by the WAPM-World Association of Perinatal Medicine and the PMF-Perinatal Medicine Foundation

A national survey on current practice of ultrasound in labor ward

OBJECTIVES

Use of ultrasonography has been suggested as an accurate adjunct to clinical evaluation of fetal position and station during labor. There are no available reports concerning its actual use in delivery wards. The aim of this survey was to evaluate the current practice regarding the use of ultrasonography during labor.

METHODS

A questionnaire was sent to members of the Italian Society of Ultrasound in Obstetrics and Gynecology employed in delivery wards. The qFeuestionnaire was made up of 22 questions evaluating participant characteristics and the current use of ultrasound in labor in their hospital of employment. The answers were grouped according to participant characteristics.

RESULTS

A total of 200 participants replied. Ultrasound was considered useful before an operative vaginal delivery by 59.6 % of respondents, while 51.8 and 52.5 % considered it useful in the management of prolonged first and second stages of labor, respectively. The major indication for ultrasound use during labor was the assessment of fetal occiput position. The major difficulties in its application were the perceived lack of training and the complexity of the ultrasound equipment use. Participants that reported fewer difficulties were those employed in hospitals with a higher number of deliveries or having delivery units with more years of experience using ultrasound in labor, or those who had attended specific training courses.

CONCLUSIONS

The results indicate that, despite the reported evidence of a higher accuracy of ultrasound compared to clinical evaluation in assessing fetal position and station, its use is still limited, even amongst maternal-fetal medicine practitioners specialized in ultrasonography.

Prediction of Failure to Progress after Labor Induction: A Multivariable Model Using Pelvic Ultrasound and Clinical Data

Objective: Labor induction is one of the leading causes of obstetric admission. This study aimed to create a simple model for predicting failure to progress after labor induction using pelvic ultrasound and clinical data. Material and Methods: A group of 387 singleton pregnant women at term with unruptured amniotic membranes admitted for labor induction were included in an observational prospective study. Clinical and ultrasonographic variables were collected at admission prior to the onset of contractions, and labor data were collected after delivery. Multivariable logistic regression analysis was applied to create several models to predict cesarean section due to failure to progress. Afterward, the most accurate and reproducible model was selected according to the lowest Akaike Information Criteria (AIC) with a high area under the curve (AUC). Results: Plausible parameters for explaining failure to progress were initially obtained from univariable analysis. With them, several multivariable analyses were evaluated. Those parameters with the highest reproducibility included maternal age (p < 0.05), parity (p < 0.0001), fetal gender (p < 0.05), EFW centile (p < 0.01), cervical length (p < 0.01), and posterior occiput position (p < 0.001), but the angle of descent was disregarded. This model obtained an AIC of 318.3 and an AUC of 0.81 (95% CI 0.76-0.86, p < 0.0001) with detection rates of 24% and 37% for FPRs of 5% and 10%. Conclusions: A simplified clinical and sonographic model may guide the management of pregnancies undergoing labor induction, favoring individualized patient management.

Artificial Intelligence, Intrapartum Ultrasound and Dystocic Delivery: AIDA (Artificial Intelligence Dystocia Algorithm), a Promising Helping Decision Support System

The position of the fetal head during engagement and progression in the birth canal is the primary cause of dystocic labor and arrest of progression, often due to malposition and malrotation. The authors performed an investigation on pregnant women in labor, who all underwent vaginal digital examination by obstetricians and midwives as well as intrapartum ultrasonography to collect four "geometric parameters", measured in all the women. All parameters were measured using artificial intelligence and machine learning algorithms, called AIDA (artificial intelligence dystocia algorithm), which incorporates a human-in-the-loop approach, that is, to use AI (artificial intelligence) algorithms that prioritize the physician's decision and explainable artificial intelligence (XAI). The AIDA was structured into five classes. After a number of "geometric parameters" were collected, the data obtained from the AIDA analysis were entered into a red, yellow, or green zone, linked to the analysis of the progress of labor. Using the AIDA analysis, we were able to identify five reference classes for patients in labor, each of which had a certain sort of birth outcome. A 100% cesarean birth prediction was made in two of these five classes. The use of artificial intelligence, through the evaluation of certain obstetric parameters in specific decision-making algorithms, allows physicians to systematically understand how the results of the algorithms can be explained. This approach can be useful in evaluating the progress of labor and predicting the labor outcome, including spontaneous, whether operative VD (vaginal delivery) should be attempted, or if ICD (intrapartum cesarean delivery) is preferable or necessary.

Oxytocin augmentation and neurotransmitters in prolonged delivery: An experimental appraisal

The uterus is a highly innervated organ, and during labor, this innervation is at its highest level. Oxytocinergic fibers play an important role in labor and delivery and, in particular, the Lower Uterine Segment, cervix, and fundus are all controlled by motor neurofibers. Oxytocin is a neurohormone that acts on receptors located on the membrane of the smooth cells of the myometrium. During the stages of labor and delivery, its binding causes myofibers to contract, which enables the fundus of the uterus to act as a mediator. The aim of this study was to investigate the presence of oxytocinergic fibers in prolonged and non-prolonged dystocic delivery in a cohort of 90 patients, evaluated during the first and second stages of labor. Myometrial tissue samples were collected and evaluated by electron microscopy, in order to quantify differences in neurofibers concentrations between the investigated and control cohorts of patients. The authors of this experiment showed that the concentration of oxytocinergic fibers differs between non-prolonged and prolonged dystocic delivery. In particular, in prolonged dystocic delivery, compared to non-prolonged dystocic delivery, there is a lower amount of oxytocin fiber. The increase in oxytocin appeared to be ineffective in patients who experienced prolonged dystocic delivery, since the dystocic labor ended as a result of the altered presence of oxytocinergic fibers detected in this group of patients.

Validation of an automated software (Smartpelvic™) in assessing hiatal area from three dimensional transperineal pelvic volumes of pregnant women: comparison with manual analysis

OBJECTIVES

The aim of this investigation was to evaluate the agreement between a manual and an automatic technique in assessing levator hiatus area (LHA) during pregnancy from three-dimensional (3D) pelvic floor volumes obtained by trans-perineal ultrasound (TPUS).

METHODS

3D volumes were acquired during rest, maximum pelvic floor contraction and Valsalva maneuver from 66 pregnant women. Manual selection of LHA and automatic software (Smart Pelvic™) were applied on TPUS volume starting from a C-plane view. To evaluate intra- and inter-observer variability measurements of LHA were performed twice by the same operator and once by a second sonographer. Reference hiatal contours obtained manually by the first operator were compared with the automated ones. Reproducibility was evaluated by intraclass correlation coefficients (ICC) and Bland-Altman plots.

RESULTS

LHA measurement, using automatic software, achieved excellent intra-observer and inter-observer reproducibility in pregnant women both at rest and after dynamic analysis (ICC>0.9). Further, an excellent agreement resulted between manual selection of the LHA and automatic imaging (ICC>0.9). The average time taken to obtain LHA manually was significantly longer when compared to the automatic analysis (p≤0.0001).

CONCLUSIONS

Smart pelvic software resulted from a reliable method for automatically measuring the LHA, showing high reproducibility and accuracy.

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.

The purple line and its association with cervical dilatation in labour: A systematic review and meta-analysis

BACKGROUND

There is a growing body of evidence that the presence and length of the purple line could represent a non-invasive method of estimating and determining labour progress.

OBJECTIVES

The primary outcome was to provide a systematic review and meta-analysis on the association between the purple line length and cervical dilatation in active labour. The secondary outcome was to determine the association between the purple line length and the fetal head descent, and to calculate the pooled mean length of the purple line at a cervical dilatation of 3-4 cm and at a cervical dilatation of 9-10 cm.

SEARCH STRATEGY

We searched the Medline, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), Clinical Trials.gov and Cochrane Pregnancy and Childbirth's Trials Register databases from inception till March 25, 2023.

SELECTION CRITERIA

We included observational studies of pregnant women in active first stage of labour who had their labour progress assessed with the use of regular vaginal examinations and who had the occurrence recorded and length of the purple line measured at the same time.

DATA COLLECTION AND ANALYSIS

Two reviewers independently evaluated study eligibility. We used the random effects and fixed effects model for meta-analysis.

MAIN RESULTS

There were six eligible studies included in the systematic review that reported on 982 women in total with the purple line appearing in 760 (77.3%) of cases. We found a moderate positive pooled correlation between the purple line length with cervical dilatation (r = +0.64; 95%CI: 0.41-0.87) and fetal head descent (r = +0.50; 95%CI: 0.32-0.68). For women either in spontaneous or induced labour, the pooled mean length of the purple line was more than 9.4 cm when the cervical dilatation was 9-10 cm, whereas it was more than 7.3 cm when the cervical dilatation was 3-4 cm.

CONCLUSIONS

The purple line is a non-invasive method that may potentially be used as an adjunct in labour progress assessment.

Use of a pocket-device point-of-care ultrasound to assess cervical dilation in labor: correlation and patient experience

OBJECTIVES

To estimate the correlation of cervical dilation between pocket-device point-of-care transperineal ultrasound (TPUS) and digital cervical examination (DCE).

METHODS

Laboring pregnant individuals ≥37 weeks of gestation presenting were prospectively evaluated for cervical dilation with a handheld pocket-sized ultrasound (Butterfly iQ+®) applied to the perineum, with a blinded DCE directly following. Subjects completed a survey to rate pain and for any preference from the examinations. To detect a moderate correlation (r=0.5) between TPUS and DCE, with an alpha of 0.05 and power of 80%, a sample size of 30 examinations were needed.

RESULTS

From April 2022 to July 2022, 30 pregnant individuals were assessed. The median cervical dilation by TPUS vs. DCE was 5.1 and 5 cm, respectively, with a Pearson's correlation coefficient, r=0.86 (95% CI 0.72 to 0.93), p<0.001. Transperineal ultrasound had a significantly less pain score than DCE, median pain score 0 vs. 2 for TPUS and DCE respectively, p<0.001. All individuals preferred the TPUS over the DCE.

CONCLUSIONS

Measurement of cervical dilation using a pocket-device point-of-care TPUS has a strong positive correlation with DCE and offers a non-invasive, convenient alternative to traditional digital exams in term, laboring patients.

Physicians' perceptions of the daily use of a handheld ultrasound device in the labor room

OBJECTIVE

The objective of our study was to describe the perception of physicians who use a handheld ultrasound (US) device in an intensive perinatal care unit.

METHODS

We conducted a prospective observational study in the labor ward of an intensive perinatal care unit between November 2021 and May 2022. Obstetrics & Gynecology residents in rotation in our department during this time were recruited as participants in this study. All the participants were provided with a handheld US device Vscan Air™ (GE Healthcare, Zipf, Austria) to use during their normal days and nights practice in labor ward. At the end of their 6 months rotation, participants completed an anonymous surveys about their perceptions of the handheld US device. The survey included questions about the ease of use in clinical situations, the amount of time of initial diagnosis, performances of the device, feasibility to use, and patient's satisfaction with the use of the device.

RESULTS

6 residents in their last year of residency were included. All the participants were satisfied with the device and would like to use it in their future practice. They all agreed that the probe was easy to handle and that the mobile application was easy to use. Image quality was always considered good by the participants and 5/6 of them declared that the handheld US device was always sufficient and did not require any confirmation with a conventional US machine. 5/6 of the participants considered that the handheld US device allowed them to gain time for clinical decision but half of them did not estimate that the use of the handheld US device improved their ability to make a clinical diagnosis.

CONCLUSION

Our study suggests that the Vscan Air™ is easy to use, with a good quality image and reduces the amount of time to make a clinical diagnosis. Handheld US device could be useful in the daily practice in maternity hospital.

Intrapartum ultrasound in maternal lateral versus semi-recumbent posture. A repeated measures study

OBJECTIVE

This study aimed to assess whether intrapartum ultrasound (ITU) measurements in maternal lateral posture are superimposable to ITU measurements in semi-recumbent position.

STUDY DESIGN

A single-center, repeated measures design was used. Women in the second stage of labor were randomized to ITU first in semi-recumbent followed by ITU in side-lying posture without and with contraction, or inversely. The angle of progression (AOP) and the head-perineum distance (HPD) between contractions (AOP1 and HPD1) and with contraction (AOP2 and HPD2) were measured in each maternal posture. The differences between AOP1 and AOP2 (dAOP), and between HPD1 and HPD2 (dHPD) were calculated.

RESULTS AND CONCLUSIONS

Forty-two women participated in the study. A generalized estimating equation model showed that AOP1 (-3.00°; 95 % CI -5.77 to -0.23; p = 0.03) and AOP2 (-4.14°; 95 % CI -7.20 to -1.08; p = 0.008) were lower in semi-recumbent compared to maternal lateral posture. HPD1 (+1.43 mm; 95 % CI 0.05-2.81; p = 0.042) and HPD2 (+1.53 mm; 95 % CI 0.17-2.89; p = 0.03) were higher in semi-recumbent position. Differences in the ITU measurements in maternal lateral posture compared to semi-recumbent position are small. Monitoring the second stage of labor with ITU in lateral maternal posture is possible.

Ultrasound Simulation for Training Trainees when the Luxury Becomes Essential: Opinion and Evidence Obtained during the Latvian Research Council Project Implementation

Background

Simulation as a proxy tool for conditional clinical training became a powerful technique for introducing trainees to the ultrasound imaging world, allowing them to become a trained sonographer taking into consideration different rates of progress in completing a specific task against the time and ensuring the long-lasting maintenance of the obtained practical skills. Adding a costly, but effective high-fidelity simulator to the residency program justified the expense, demonstrating efficiency of training for improving the clinical performance and confidence of trainees.

Materials and methods

A pilot study in Riga Maternity Hospital within the framework of the study "Role of metabolome, biomarkers and ultrasound parameters in successful labor induction" (Fundamental and Applied Research Programme lzp-2021/1-0300) was performed between March 1st 2022 and 31st April 2022. A virtual-reality simulator (ScanTrainer, MedaphorTM, Cardiff, UK) was used with the teaching module for assessment of the uterine cervix. Five trainees in obstetrics and two young specialists included in the study. None of them had Fetal Medicine Foundation certificate of competence in the assessment of the uterine cervical lenght before. The time used on the simulator, the number of simulations and a mean confidence in cervical length assessment before and after simulation were recorded.

Results

The study on assesment of uterine cervical lenght demonstrated statistically significant increase in confidence (p=0.008) and statistically significant decrease in time needed to complete correctly the same tasks for the trainees (p=0.008) that shows a positive learning curve over the time of training on ScanTrainer, Medaphor.

Conclusions

The simple task allows to become a certified specialist in uterine cervical assessment in the short period of time. That support the productiveness of the simulation-based education. The training program should be updated taking into consideration simulation curriculum.