ISUOG Practice Guidelines: intrapartum ultrasound

PSFHS: Intrapartum ultrasound image dataset for AI-based segmentation of pubic symphysis and fetal head

During the process of labor, the intrapartum transperineal ultrasound examination serves as a valuable tool, allowing direct observation of the relative positional relationship between the pubic symphysis and fetal head (PSFH). Accurate assessment of fetal head descent and the prediction of the most suitable mode of delivery heavily rely on this relationship. However, achieving an objective and quantitative interpretation of the ultrasound images necessitates precise PSFH segmentation (PSFHS), a task that is both time-consuming and demanding. Integrating the potential of artificial intelligence (AI) in the field of medical ultrasound image segmentation, the development and evaluation of AI-based models rely significantly on access to comprehensive and meticulously annotated datasets. Unfortunately, publicly accessible datasets tailored for PSFHS are notably scarce. Bridging this critical gap, we introduce a PSFHS dataset comprising 1358 images, meticulously annotated at the pixel level. The annotation process adhered to standardized protocols and involved collaboration among medical experts. Remarkably, this dataset stands as the most expansive and comprehensive resource for PSFHS to date.

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.

RTSeg-net: A lightweight network for real-time segmentation of fetal head and pubic symphysis from intrapartum ultrasound images

The segmentation of the fetal head (FH) and pubic symphysis (PS) from intrapartum ultrasound images plays a pivotal role in monitoring labor progression and informing crucial clinical decisions. Achieving real-time segmentation with high accuracy on systems with limited hardware capabilities presents significant challenges. To address these challenges, we propose the real-time segmentation network (RTSeg-Net), a groundbreaking lightweight deep learning model that incorporates innovative distribution shifting convolutional blocks, tokenized multilayer perceptron blocks, and efficient feature fusion blocks. Designed for optimal computational efficiency, RTSeg-Net minimizes resource demand while significantly enhancing segmentation performance. Our comprehensive evaluation on two distinct intrapartum ultrasound image datasets reveals that RTSeg-Net achieves segmentation accuracy on par with more complex state-of-the-art networks, utilizing merely 1.86 M parameters-just 6 % of their hyperparameters-and operating seven times faster, achieving a remarkable rate of 31.13 frames per second on a Jetson Nano, a device known for its limited computing capacity. These achievements underscore RTSeg-Net's potential to provide accurate, real-time segmentation on low-power devices, broadening the scope for its application across various stages of labor. By facilitating real-time, accurate ultrasound image analysis on portable, low-cost devices, RTSeg-Net promises to revolutionize intrapartum monitoring, making sophisticated diagnostic tools accessible to a wider range of healthcare settings.

Descent of the presenting part assessed with ultrasound

Fetal head descent can be expressed as fetal station and engagement. Station is traditionally based on clinical vaginal examination of the distal part of the fetal skull and related to the level of the ischial spines. Engagement is based on a transabdominal examination of the proximal part of the fetal head above the pelvic inlet. Clinical examinations are subjective, and objective measurements of descent are warranted. Ultrasound is a feasible diagnostic tool in labor, and fetal lie, station, position, presentation, and attitude can be examined. This review presents an overview of fetal descent examined with ultrasound. Ultrasound was first introduced for examining fetal descent in 1977. The distance from the sacral tip to the fetal skull was measured with A-mode ultrasound, but more convenient transperineal methods have since been published. Of those, progression distance, angle of progression, and head-symphysis distance are examined in the sagittal plane, using the inferior part of the symphysis pubis as reference point. Head-perineum distance is measured in the frontal plane (transverse transperineal scan) as the shortest distance from perineum to the fetal skull, representing the remaining part of the birth canal for the fetus to pass. At high stations, the fetal head is directed downward, followed with a horizontal and then an upward direction when the fetus descends in the birth canal and deflexes the head. Head descent may be assessed transabdominally with ultrasound and measured as the suprapubic descent angle. Many observational studies have shown that fetal descent assessed with ultrasound can predict labor outcome before induction of labor, as an admission test, and during the first and second stage of labor. Labor progress can also be examined longitudinally. The International Society of Ultrasound in Obstetrics and Gynecology recommends using ultrasound in women with prolonged or arrested first or second stage of labor, when malpositions or malpresentations are suspected, and before an operative vaginal delivery. One single ultrasound parameter cannot tell for sure whether an instrumental delivery is going to be successful. Information about station and position is a prerequisite, but head direction, presentation, and attitude also should be considered.

Real-time ultrasound to assist during a vaginal breech delivery

We report a novel application of intrapartum sonography, herein used to assist the internal podalic version and the vaginal delivery of a transverse-lying second twin. Following the vaginal delivery of the first cephalic twin, the internal podalic version was performed under continuous ultrasound vision, leading to the uncomplicated breech delivery of a healthy neonate.

Prevention of obstetric anal sphincter injuries with perineal support and lateral episiotomy: A historical cohort study

INTRODUCTION

There are many risk factors for obstetric anal sphincter injury (OASIS) and the interaction between these risk factors is complex and understudied. The many observational studies that have shown a reduction of OASIS rates after implementation of perineal support have short follow-up time. We aimed to study the effect of integration of active perineal support and lateral episiotomy on OASIS rates over a 15-year period and to study interactions between risk factors known before delivery.

MATERIAL AND METHODS

We performed a historical cohort study over the periods 1999-2006 and 2007-2021 at Stavanger University Hospital, Norway. The main outcome was OASIS rates. Women without a previous cesarean section and a live singleton fetus in cephalic presentation at term were eligible. The department implemented in 2007 the Finnish concept of active perineal protection, which includes support of perineum, control of fetal expulsion, good communication with the mother and observation of perineal stretching. The practice of mediolateral episiotomy was replaced with lateral episiotomy when indicated. We analyzed the OASIS rates in groups with and without episiotomy stratified for delivery mode, fetal position at delivery and for parity, and adjusted for possible confounders (maternal age, gestational age, oxytocin augmentation and epidural analgesia).

RESULTS

We observed a long-lasting reduction in OASIS rates from 4.9% to 1.9% and an increase in episiotomy rates from 14.4% to 21.8%. Lateral episiotomy was associated with lower OASIS rates in nulliparous women with instrumental vaginal deliveries and occiput anterior (OA) position; 3.4% vs 10.1% (OR 0.31; 95% CI: 0.24-0.40) and 6.1 vs 13.9% (OR 0.40; 95% CI: 0.19-0.82) in women with occiput posterior (OP) position. Lateral episiotomy was also associated with lower OASIS rates in nulliparous women with spontaneous deliveries and OA position; 2.1% vs 3.2% (OR 0.62; 95% CI: 0.49-0.80). The possible confounders had little confounding effects on the risk of OASIS in groups with and without episiotomy.

CONCLUSIONS

We observed a long-lasting reduction in OASIS rates after implementation of preventive procedures. Lateral episiotomy was associated with lower OASIS rates in nulliparous women with an instrumental delivery. Special attention should be paid to deliveries with persistent OP position.

Current status of the position on labor progress prediction for contemporary pregnant women using Friedman curves: An updated review

AIM

Prediction of labor progression is important for maternal and fetal health, as improved accuracy can lead to more timely intervention and improved outcomes. This review aims to outline the importance of predicting the progression of spontaneous parturition, detail the various methods employed to enhance this prediction and provide recommendations for future research.

METHODS

We searched articles relating to labor progression and systematic review articles on Artificial Inteligence (AI) in childbirth management using PubMed. To supplement, Google Scholar was used to find recent guidelines and related documents.

RESULTS

Traditional methods like vaginal examinations, criticized for subjectivity and inaccuracy, are gradually being replaced by ultrasound, considered a more objective and accurate approach. Further advancements have been observed with machine learning and artificial intelligence techniques, which promise to surpass the accuracies of conventional methods. The Friedman curve, developed in 1954, is the standard for assessing labor progress, but its application to Asian women, in particular, remains controversial, and various studies have reported that the actual rate of labor was slower than that indicated by the Friedman curve.

CONCLUSION

There is a need to innovate methodologies for predicting delivery tailored to modern pregnant women, especially when they have different genetic and cultural backgrounds than their Western counterparts, such as Asians. Future research should develop predictive models of labor progression that aim to enhance medical intervention and improve the safety and well-being of both mother and child.

Parturition at term: induction, second and third stages of labor, and optimal management of life-threatening complications-hemorrhage, infection, and uterine rupture

Childbirth is a defining moment in anyone's life, and it occurs 140 million times per year. Largely a physiologic process, parturition does come with risks; one mother dies every two minutes. These deaths occur mostly among healthy women, and many are considered preventable. For each death, 20 to 30 mothers experience complications that compromise their short- and long-term health. The risk of birth extends to the newborn, and, in 2020, 2.4 million neonates died, 25% in the first day of life. Hence, intrapartum care is an important priority for society. The American Journal of Obstetrics & Gynecology has devoted two special Supplements in 2023 and 2024 to the clinical aspects of labor at term. This article describes the content of the Supplements and highlights new developments in the induction of labor (a comparison of methods, definition of failed induction, new pharmacologic agents), management of the second stage, the value of intrapartum sonography, new concepts on soft tissue dystocia, optimal care during the third stage, and common complications that account for maternal death, such as infection, hemorrhage, and uterine rupture. All articles are available to subscribers and non-subscribers and have supporting video content to enhance dissemination and improve intrapartum care. Our hope is that no mother suffers because of lack of information.

Soft-tissue dystocia due to paradoxical contraction of the levator ani as a cause of prolonged second stage: concept, diagnosis, and potential treatment

Smaller pelvic floor dimensions seem to have been an evolutionary need to provide adequate support for the pelvic organs and the fetal head. Pelvic floor dimension and shape contributed to the complexity of human birth. Maternal pushing associated with pelvic floor muscle relaxation is key to vaginal birth. Using transperineal ultrasound, pelvic floor dimensions can be objectively measured in both static and dynamic conditions, such as pelvic floor muscle contraction and pushing. Several studies have evaluated the role of the pelvic floor in labor outcomes. Smaller levator hiatal dimensions seem to be associated with a longer duration of the second stage of labor and a higher risk of cesarean and operative deliveries. Furthermore, smaller levator hiatal dimensions are associated with a higher fetal head station at term of pregnancy, as assessed by transperineal ultrasound. With maternal pushing, most women can relax their pelvic floor, thus increasing their pelvic floor dimensions. Some women contract rather than relax their pelvic floor muscles under pushing, which is associated with a reduction in the anteroposterior diameter of the levator hiatus. This phenomenon is called levator ani muscle coactivation. Coactivation in nulliparous women at term of pregnancy before the onset of labor is associated with a higher fetal head station at term of pregnancy and a longer duration of the second stage of labor. In addition, levator ani muscle coactivation in nulliparous women undergoing induction of labor is associated with a longer duration of the active second stage of labor. Whether we can improve maternal pelvic floor relaxation with consequent improvement in labor outcomes remains a matter of debate. Maternal education, physiotherapy, and visual feedback are promising interventions. In particular, ultrasound visual feedback before the onset of labor can help women increase their levator hiatal dimensions and correct levator ani muscle coactivation in some cases. Ultrasound visual feedback in the second stage of labor was found to help women push more efficiently, thus obtaining a lower fetal head station at ultrasound and a shorter duration of the second stage of labor. The available evidence on the role of any intervention aimed to aid women to better relax their pelvic floor remains limited, and more studies are needed before considering its routine clinical application.

Safety and efficacy of the OdonAssist inflatable device for assisted vaginal birth: the BESANCON ASSIST study

BACKGROUND

The first feasibility study of the OdonAssist inflatable device for use in clinically indicated assisted vaginal birth reported a success rate of 48% with no significant safety concerns. Additional studies exploring the device performance in other clinical settings are warranted before definitive conclusions can be drawn about its safety and efficacy in current practice.

OBJECTIVE

This study aimed to investigate the safety and efficacy of the OdonAssist before conducting a randomized controlled trial.

STUDY DESIGN

This was an open-label, nonrandomized study of 104 women with a clinically indicated assisted vaginal birth using the OdonAssist at the Besancon University Hospital, France. Data, including those of a nested cohort group of women who had an assisted vaginal birth using vacuum or spatulas because a trained OdonAssist device operator was not available at the time of delivery, were collected. The primary outcome measure was the proportion of successful assisted vaginal births using the OdonAssist. Neonatal outcome data were reviewed at days 1 and 28, and maternal outcomes were investigated up to day 90.

RESULTS

Between December 2019 and May 2021, 2191 pregnant women were approached, and 83% (1636/1973) of them consented to participate in the study. Among them, 10.7% (176/1636) required an assisted vaginal birth owing to a vertex presentation at +1 and below. The OdonAssist was used in 59% of births (104/176), and 41.1% (72/176) of the participants were included in the nested cohort group. The rate of successful assisted vaginal births using the OdonAssist was 88.5% (92/104). No emergency cesarean deliveries were performed in the OdonAssist group. There were no serious adverse maternal or neonatal reactions related to the use of the device. The rate of third- and fourth-degree perineal tears with the OdonAssist was 3.8% (4/104). The maternal perception ratings of the birth experience with the OdonAssist (collected on days 1, 7, and 28 using a 15-point scale) were high. In addition, the operators reported a positive perception of the device, with ease of use across the different steps of the procedure. One single technique was used for all vertex fetal head positions.

CONCLUSION

The OdonAssist is a safe and effective alternative to other current devices for assisted vaginal births. The high acceptance rate (83%) among pregnant women and the high rate of successful assisted vaginal births using the OdonAssist confirm the feasibility of a future randomized controlled trial.

The predicting value of the ratio of levator hiatus diameter to fetal head circumference in pregnant women at 37 weeks of gestation in the progression of the second stage of labor and levator ani injury 6 weeks postpartum

Objective

This study investigated the predicting value of the ratio of levator hiatus diameter (LHS) to fetal head circumference (HC) in pregnant women at 37 weeks of gestation in the progression of the second stage of labor and levator ani injury 6 weeks postpartum.

Methods

A total of 120 first-time women who gave vaginal delivery at 37 weeks of pregnancy were selected as the subjects in our hospital during March 2021 to March 2022. The subjects were divided into the second stage of labor > 1 h group and the second stage of labor ≤ 1 h group, according to the delivery time of the second stage of labor. According to the 6-week postpartum follow-up ultrasound examination with or without levator ani injury, they were divided into levator ani injury group and no injury group. All primipara women underwent three-dimensional ultrasonography at 37 weeks of gestation, and the resting LHS, Valsalva LHS, fetal HC and the ratio of resting LHS and fetal HC were compared. The correlation between these factors and the length of the second labor stage was analyzed using Pearson correlation analysis. The value of these factors in predicting labor progression and postpartum levator ani injury was assessed by receiver operating characteristic (ROC) curves.

Results

The resting LHS, Valsalva LHS and the ratio of resting LHS and fetal HC in the levator ani injury group were lower than these in the no injury group, while fetal HC in the levator ani injury group was higher than that in the no injury group (P < 0.05). The resting LHS, Valsalva LHS and the ratio of resting LHS and fetal HC in the second stage of labor > 1 h group were lower than these in the second stage of labor ≤ 1 h group, while fetal HC in the second stage of labor > 1 h group was higher than that in the second stage of labor ≤ 1 h group (P < 0.05). A significant negative correlation was observed between resting LHS/HC and total labor process (=-0.333, P < 0.01). ROC curve analysis showed that the AUCs of resting LHS, Valsalva LHS, HC, and resting LHS/HC ratio in predicting prolongation of the second stage of labor were 0.741, 0.740, 0.702, and 0.843 respectively. Besides, the AUCs of resting LHS, Valsalva LHS, HC, and resting LHS/HC ratio in predicting the total labor process were 0.657, 0.684, 0.768, and 0.836 respectively. The AUCs of resting LHS, Valsalva LHS, HC, and resting LHS/HC ratio in predicting postpartum levator ani muscle injury were 0.769, 0.773, 0.747, and 0.885 respectively.These results suggested that the ratio of resting LHS and fetal HC may have certain clinical value in predicting levator ani injury in pregnant women.

Conclusion

LHS, fetal HC and the ratio of resting LHS and fetal HC are significantly correlated with labor progression and postpartum levator ani injury, which have certain value in predicting labor progress and postpartum levator ani injury. Therein, the ratio of resting LHS and fetal HC has the highest predictive value, and early detection of the ratio of resting LHS and fetal HC is helpful to guide the selection of appropriate delivery mode.

Ultrasonographic Evaluation of the Second Stage of Labor according to the Mode of Delivery: A Prospective Study in Greece

BACKGROUND AND OBJECTIVES

Accurate diagnosis of labor progress is crucial for making well-informed decisions regarding timely and appropriate interventions to optimize outcomes for both the mother and the fetus. The aim of this study was to assess the progress of the second stage of labor using intrapartum ultrasound.

MATERIAL AND METHODS

This was a prospective study (December 2022-December 2023) conducted at the Third Department of Obstetrics and Gynecology, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Greece. Maternal-fetal and labor characteristics were recorded, and two ultrasound parameters were measured: the angle of progression (AoP) and the head-perineum distance (HPD). The correlation between the two ultrasonographic values and the maternal-fetal characteristics was investigated. Multinomial regression analysis was also conducted to investigate any potential predictors of the mode of delivery.

RESULTS

A total of 82 women at the second stage of labor were clinically and sonographically assessed. The mean duration of the second stage of labor differed between vaginal and cesarean deliveries (65.3 vs. 160 min; p-value < 0.001) and between cesarean and operative vaginal deliveries (160 vs. 88.6 min; p-value = 0.015). The occiput anterior position was associated with an increased likelihood of vaginal delivery (OR: 24.167; 95% CI: 3.8-152.5; p-value < 0.001). No significant differences were identified in the AoP among the three different modes of delivery (vaginal: 145.7° vs. operative vaginal: 139.9° vs. cesarean: 132.1°; p-value = 0.289). The mean HPD differed significantly between vaginal and cesarean deliveries (28.6 vs. 41.4 mm; p-value < 0.001) and between cesarean and operative vaginal deliveries (41.4 vs. 26.9 mm; p-value = 0.002); it was correlated significantly with maternal BMI (r = 0.268; p-value = 0.024) and the duration of the second stage of labor (r = 0.256; p-value = 0.031). Low parity (OR: 12.024; 95% CI: 6.320-22.876; p-value < 0.001) and high HPD (OR: 1.23; 95% CI: 1.05-1.43; p-value = 0.007) were found to be significant predictors of cesarean delivery.

CONCLUSIONS

The use of intrapartum ultrasound as an adjunctive technique to the standard clinical evaluation may enhance the diagnostic approach to an abnormal labor progress and predict the need for operative vaginal or cesarean delivery.

Prediction of persistent occiput posterior position by sonographic assessment of fetal head attitude at start of second stage of labor: prospective study

OBJECTIVES

To evaluate the relationship between the attitude of the fetal head quantified by means of the chin-to-chest angle (CCA) in fetuses in occiput posterior (OP) position at the beginning of the second stage of labor, and persistent OP position at birth.

METHODS

This was a single-center, prospective observational study conducted at the University Hospital of Parma, Parma, Italy. We included singleton pregnancies at term with fetuses in the OP position at the beginning of the second stage of labor. The fetal head position, station by means of angle of progression and head-to-perineum distance, and attitude by means of CCA were assessed using transabdominal or transperineal ultrasound. The primary outcome was persistent OP position at birth.

RESULTS

Between January and July 2022, 76 women were included in the study. There were 48 (63.2%) spontaneous rotations of the fetal head and spontaneous vaginal delivery occurred in all. Among the 28 (36.8%) fetuses that did not rotate spontaneously into an occiput anterior position, eight (28.6%) had a spontaneous vaginal delivery, while operative vaginal delivery and Cesarean delivery was performed in 11 (39.3%) and nine (32.1%) cases, respectively. Multivariable logistic regression analysis showed that the CCA (adjusted odds ratio (aOR), 2.15 (95% CI, 1.22-3.78); P = 0.008) and nulliparity (aOR, 0.20 (95% CI, 0.06-0.76); P = 0.02) were associated independently with persistent OP position at birth. Moreover, the CCA showed an area under the receiver-operating-characteristics curve of 0.69 (95% CI, 0.56-0.82); P = 0.005) for the prediction of persistent OP position. The optimal cut-off value of the CCA was 36.5°, and was associated with a sensitivity of 0.82 (95% CI, 0.63-0.94), specificity of 0.50 (95% CI, 0.35-0.65), positive predictive value of 0.49 (95% CI, 0.34-0.64), negative predictive value of 0.83 (95% CI, 0.64-0.94), positive likelihood ratio of 1.64 (95% CI, 1.18-2.29) and negative likelihood ratio of 0.36 (95% CI, 0.15-0.83).

CONCLUSIONS

Our data show that, within a population of women with fetal OP position at the beginning of the second stage of labor, the sonographic fetal head attitude measured by means of the CCA might help in the identification of fetuses at risk of persistent OP position. Such findings can be useful for patient counseling when OP position is diagnosed at full cervical dilatation. Further studies should investigate if the CCA might select patients who may benefit from manual rotation of the fetal head. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Level of agreement between midwives and obstetricians performing ultrasound examination during labor

OBJECTIVE

To evaluate the level of agreement between ultrasound measurements to evaluate fetal head position and progress of labor by attending midwives and obstetricians after appropriate training.

METHODS

In this prospective study, women in the first stage of labor giving birth to a single baby in cephalic presentation at our Obstetric Unit between March 2018 and December 2019 were invited to participate; 109 women agreed. Transperineal and transabdominal ultrasound was independently performed by a trained midwife and an obstetrician. Two paired measurements were available for comparisons in 107 cases for the angle of progression (AoP), in 106 cases for the head-to-perineum distance (HPD), in 97 cases for the cervical dilatation (CD), and in 79 cases for the fetal head position.

RESULTS

We found a good correlation between the AoP measured by obstetricians and midwives (intra-class correlation coefficient [ICC] = 0.85; 95% confidence interval [CI] 0.80-0.89). There was a moderate correlation between the HPD (ICC = 0.75; 95% CI 0.68-0.82). There was a very good correlation between the CD measured (ICC = 0.94; 95% CI 0.91-0.96). There was a very good level of agreement in the classification of the fetal head position (Cohen's κ = 0.89; 95% CI 0.80-0.98).

CONCLUSIONS

Ultrasound assessment of fetal head position and progress of labor can effectively be performed by attending midwives without previous experience in ultrasound.

Intrapartum transperineal ultrasound: angle of progression to evaluate and predict the mode of delivery and labor progression

Intrapartum ultrasonography serves as a valuable tool for the objective evaluation of labor progression and effectively identifies underlying factors, such as asynclitism, in cases of abnormal labor progression. Among the various ultrasound measurement techniques, the angle of progression (AOP) demonstrates favorable reproducibility and accuracy in assessing fetal head descent. In the context of abnormal labor, interventions differ across different stages of labor, emphasizing the importance of investigating the utility of AOP according to labor stages in this review article. Pre-labor assessment of AOP can be beneficial in terms of counseling for the timing of induction of labor, while a wider AOP value during the prolonged first stage of labor has demonstrated a positive correlation with successful vaginal delivery and shorter time to delivery. In the second stage of labor, the AOP has exhibited efficacy in predicting the mode of delivery and complicated operative deliveries. Furthermore, it has assisted in predicting the duration of labor, thereby highlighting its potential as a decision-making model for labor progression. However, further research is needed to investigate aspects, such as the determination of cutoff values, of AOP, considering the multifaceted characteristics of labor progression, which are influenced by complex interactions among maternal, fetal, and other contributing factors.

Serum biomarkers of hypoxic-ischemic brain injury

Brain injury is a multifaceted condition arising from nonspecific damage to nervous tissue. The resulting cognitive developmental impairments reverberate through patients' lives, affecting their families, and even the broader economic landscape. The significance of early brain injury detection lies in its potential to stave off severe consequences and enhance the effectiveness of tailored therapeutic interventions. While established methods like neuroimaging and neurophysiology serve as valuable diagnostic tools, their demanding nature restricts their accessibility, particularly in scenarios such as small hospitals, nocturnal or weekend shifts, and cases involving unstable patients. Hence, there is a pressing need for more accessible and efficient diagnostic avenues. Among the spectrum of brain injuries, hypoxic-ischemic encephalopathy stands out as a predominant affliction in the pediatric population. Diagnosing brain injuries in newborns presents challenges due to the subjective nature of assessments like Apgar scores and the inherent uncertainty in neurological examinations. In this context, methods like magnetic resonance and ultrasound hold recommendations for more accurate diagnosis. Recognizing the potential of serum biomarkers derived from blood samples, this paper underscores their promise as a more expedient and resource-efficient means of assessing brain injuries. The review compiles current insights into serum biomarkers, drawing from experiments conducted on animal models as well as human brain pathologies. The authors aim to elucidate specific characteristics, temporal profiles, and the available corpus of experimental and clinical data for serum biomarkers specific to brain injuries. These include neuron-specific enolase (NSE), ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), S100 calcium-binding protein beta (S100B), glial fibrillary acidic protein (GFAP), and high-mobility-group-protein-box-1 (HMGB1). This comprehensive endeavor contributes to advancing the understanding of brain injury diagnostics and potential avenues for therapeutic intervention.

Admission ultrasonography as a means of identifying unrecognized fetal compromise in term singleton pregnancies at the onset of labor - a feasibility study

OBJECTIVES

Apparently uncomplicated low-risk pregnancies, especially first time births, account for a significant proportion of adverse birth outcomes. Improved risk stratification with a simple bedside scan on admission in early labor could potentially reduce adverse intrapartum outcomes. The aim of this feasibility study was to assess a cohort of low-risk subjects with admission ultrasonography at the onset of labor with a view to conducting a future randomized controlled trial (RCT). The objectives were three-fold; i) to determine the logistics of performing a labor admission ultrasound scan ii) to establish whether abnormal ultrasound features can be identified and iii) whether they are associated with emergency delivery and/or poor condition of the neonate at birth.

METHODS

We performed a prospective cohort study of 295 participants with term singleton cephalic pregnancies admitted in early labor or for labor induction with non-fetal indications. The setting was a university teaching hospital in Ireland with almost 8000 births annually. A bedside ultrasound scan was performed to assess fetal biometry, amniotic fluid volume and placental maturity. Patients and their babies were followed up until hospital discharge. The outcomes of interest included image quality, time to perform a scan, oligohydramnios (Single Deepest Pool ≤ 2 cm), small for gestational age (SGA; abdominal circumference <10th centile), mature placenta (Grannum 2 or 3), pathological CTG, emergency cesarean section (CS), fetal acidosis (cord arterial pH <7.10 or base excess <-12.0), low Apgar score <7 at 5 min and neonatal unit admission.

RESULTS

Image quality was optimal in 274 of the 295 scans (93%) and 271 (92%) were completed in less than 10 min. Of this low-risk population, 67 of 294 (23%) had oligohydramnios, 11 (4%) were small for gestational age and 87 (30%) had a mature placenta (Grannum grade 2). The incidence of pathological CTG and emergency CS was higher among patients with oligohydramnios than those with a normal scan but did not reach statistical significance; Odds Ratio 3.40 (95% Confidence Intervals 0.55 to 20.92) and OR 1.43 (95% CI 0.66 to 3.08) respectively. The mean birthweight was significantly lower in those with oligohydramnios -139 g (95% CI -248 to -30) and admission scan detected SGA -357 g (95% CI -557 to -137). Adverse perinatal outcomes were uncommon with a higher incidence of fetal acidosis (pH < 7.10) in the oligohydramnios group. The incidence of neonatal unit admission >24 h was higher in the oligohydramnios group but not statistically significant; OR 3.75 (95% CI 0.61 to 22.97). Results for SGA alone were non-significant and results for oligohydramnios and SGA combined were similar to those for oligohydramnios alone.

CONCLUSIONS

Admission ultrasonography is feasible in a routine clinical setting, but evidence of benefit is weak and does not currently justify a randomized controlled trial.

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.

Accurate evaluation of the progress of delivery with transperineal ultrasound may improve vaginal delivery: a single-center retrospective study

Although digital examination of the cervix is the standard method used worldwide for evaluating the progress of delivery, it is subjective. Transperineal ultrasound (TPU) is combined with digital evaluation for accurate assessment of fetal descent and rotation of the advanced part of the fetus. This retrospective study aimed to clarify the impact of introducing TPU on perinatal outcomes at Mie University Hospital. We analyzed singleton pregnant women who underwent delivery management at our hospital between April 2020 and March 2021. Perinatal outcomes were compared between patients who used TPU (TPU+ group) and those who did not (TPU- group). The angle of progression and head direction were measured. The rate of vaginal delivery was significantly increased (90.9% vs. 71.6%; P = 0.0017), and the second stage of labor was significantly prolonged in the TPU+ group (148.1 vs. 75.8 min; P < 0.0001). A significant difference was observed in termination in the latent phase between the TPU+ group [3/8 (37.5%) cases] and TPU- group [20/25 (80.0%) cases] (P = 0.036). The rate of vaginal delivery can be increased through accurate evaluation of the progress of delivery with TPU.

Intrapartum ultrasound for fetal head asynclitism: Is it possible to establish a degree of asynclitism to correlate to delivery outcome?

OBJECTIVE

To investigate the role of intrapartum ultrasound (IU) in the diagnosis of asynclitism and the importance of asynclitism degree in labor outcomes.

METHOD

This prospective cohort study included 41 low-risk pregnant women with fetus in singleton-vertex. The IU assessment to diagnose asynclitism was performed during labor at two specific steps, including the suspicion and/or diagnosis of labor arrest. The "four-chamber view" and "squint sign without nose" were classified as marked/severe asynclitism. The "midline deviation" and "squint sign with nose" findings were classified as moderate asynclitism. Obstetric outcomes and maternal-fetal complications were compared with the degree of asynclitism.

RESULTS

Severe and moderate asynclitism was seen in 17 (41.7%), 10 (58.8%) and seven (41.2%) women, respectively. All pregnant women diagnosed with asynclitism delivered by vacuum extraction (VE) or cesarean section (CS). CS was performed in nine patients with asynclitism (52.9%). The difference between asynclitism type and VE/CS ratios was statistically significant (P = 0.039). Four fetuses with squint sign without nose delivered by VE. A significant correlation was seen between the presence of squint without nose sign and second-/third-degree perineal injury.

CONCLUSION

Severe asynclitism is associated with increasing operative birth and maternal-fetal complications. Detection of asynclitism degree by IU could be useful, alerting the obstetrics team to possible perinatal problems during delivery.

Prediction of mode of delivery by an ultrasound score similar to Bishop score and performance of independent predictors

INTRODUCTION

There is evolving literature on the superiority of transperineal ultrasound (TPU) in predicting the mode of delivery either before induction or during the course of labour. An ultrasound score (USG score) similar to a Bishop score or an ultrasound scoring method based on independent predictors before the onset of labour at term gestation would serve as a baseline objective record over which further progress of labour could be evaluated.

OBJECTIVE

1. To sonographically examine the clinical parameters evaluated during a digital examination. 2. To derive an USG score using TPU parameters, similar to a Bishop score, and determine its performance in predicting pregnancy outcomes. 3. To identify which are the independent predictors of caesarean section among all the studied ultrasound (USG) parameters.

MATERIALS AND METHODS

In this prospective study, all the eligible women who came for routine antenatal care at term gestation and who were due for pelvic assessment were recruited. They underwent transabdominal ultrasound (TAS) for evaluating head position and head circumference, and TPU for evaluating head station with and without applying fundal pressure, various cervical parameters, sub pubic angle. Equivalent five USG parameters were scored along similar lines as the Bishop score. These women underwent vaginal examination for Bishop score and pelvic adequacy by an obstetrician who was blinded about USG parameters. While spontaneous onset of labour (SOL) was awaited in some of these women, some were induced as and when indicated. After delivery, the Bishop scores, pregnancy outcome in terms of SOL or induction of labour (IOL), mode of delivery and duration of labour were noted retrospectively from case records. Independent predictors of caesarean were obtained by univariate and multivariate analysis.

RESULTS

All the parameters were assessed for predictive ability of caesarean section by univariate analysis. The cervical length, angle of progression (AOP) at rest, head perineal distance (HPD) at rest and with pressure, Bishop score and USG score were found significant. On multivariate analysis, cervix length and USG score were found to be statistically significant. At a USG score of ≤ 5, the sensitivity and specificity to predict caesarean section were 84% and 68%, respectively. The relative risk (RR) was 4.9 (95% CI 2.3-12). The USG score could predict SOL. The p value was 0.001. The area under the curve (AUC) for the ultrasound score was 0.74.

CONCLUSIONS

USG examination by USG score at term gestation before the onset of labour can predict mode of delivery by caesarean section. It can predict spontaneous onset of labour. However, among all the individual parameters, cervix length has best predictive ability for caesarean section.

Use of artificial intelligence and deep learning in fetal ultrasound imaging

Deep learning is considered the leading artificial intelligence tool in image analysis in general. Deep-learning algorithms excel at image recognition, which makes them valuable in medical imaging. Obstetric ultrasound has become the gold standard imaging modality for detection and diagnosis of fetal malformations. However, ultrasound relies heavily on the operator's experience, making it unreliable in inexperienced hands. Several studies have proposed the use of deep-learning models as a tool to support sonographers, in an attempt to overcome these problems inherent to ultrasound. Deep learning has many clinical applications in the field of fetal imaging, including identification of normal and abnormal fetal anatomy and measurement of fetal biometry. In this Review, we provide a comprehensive explanation of the fundamentals of deep learning in fetal imaging, with particular focus on its clinical applicability. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

A retrospective cohort study of the characteristics of unsuccessful operative vaginal deliveries

INTRODUCTION

Unsuccessful operative vaginal delivery (OVD) is associated with high rates of materno-fetal morbidity. We aimed to examine institutional rates of unsuccessful OVDs (uOVD) and compare them with successful OVD (sOVD) in order to identify factors to aid patient selection and education.

METHODS

A 6-month retrospective cohort study was performed on all unsuccessful and successful OVDs in a tertiary level maternity hospital in the Republic of Ireland. Maternal demographics and obstetric factors were assessed to evaluate potential underlying risk factors for unsuccessful operative vaginal delivery versus successful vaginal delivery.

RESULTS

There were 4,191 births during the study period with an OVD rate of 14.2% (n = 595) with 28 (4.7% of OVDs) being unsuccessful. Unsuccessful OVD were predominately nulliparous (25; 89.2%) with a mean maternal age of 30.1 years (range 20-42), with more than half (n = 15, 53.5%) being induced. The most common indication for induction was prolonged rupture of membranes (PROM) (n = 7, 25%) which was significantly different from the successful OVD group. A senior obstetrician was significantly more likely to be the primary operator in uOVD when compared to sOVD. (82.1 % V 54.1% p < 0.01). The majority of unsuccessful OVD were vacuum deliveries (n = 17; 60.7%), with a significantly higher mean birthweight when compared to successful OVD (3.695 kg V 3.483 kg; p < 0.01). Following an unsuccessful OVD, women were more likely to have a postpartum haemorrhage (64.2 % V 31.5% p < 0.01) and their infant was more likely to require admission to the neonatal intensive care unit (NICU) (32.1 % V 5.8% p < 0.01) when compared with successful OVD.

CONCLUSION

Risk factors for unsuccessful OVD were higher birth weight and induction of labour. There was a higher incidence of postpartum haemorrhage and NICU admission when compared with successful OVD.

Impact of additional theoretical training program in the diagnosis of the fetal head position during labor: a prospective observational study

BACKGROUND

The accuracy of transvaginal digital examination in determining foetal head position is not high enough. This study aimed to evaluate whether an additional training on our new theory could improve the diagnostic accuracy of the foetal head position.

METHODS

This was a prospective study conducted at a 3a grade hospital. The study included 2 residents in their first year of training in obstetrics without prior experience in transvaginal digital examination. In the observational study, 600 pregnant women without contraindications to vaginal delivery were included. Two residents were simultaneously trained in the theory of traditional vaginal examination, but resident B received an additional theoretical training program. The pregnant women were randomly assigned to have the foetal head position examined by resident A and resident B. The foetal head position was then confirmed by ultrasound, which was performed by the main investigator. After 300 examinations were independently performed by each resident, the accuracy of foetal head position and perinatal outcomes were compared between the two groups.

RESULTS

During the 3-month period, 300 post training transvaginal digital examinations were performed by each resident in our hospital. The two groups were found to be homogeneous for age at delivery, BMI before delivery, parity, gestational weeks at delivery, the rate of epidural analgesia, foetal head position, presence of caput succedaneum, presence of moulding and foetal head station(p > 0.05). The diagnostic accuracy of head position by digital examination was higher for resident B, who was subjected to an additional theoretical training program, than for resident A (75.00% vs. 60.67%, p < 0.001). There were no significant differences in maternal and neonatal outcomes between the two groups (p > 0.05).

CONCLUSION

An additional theoretical training program for residents increased the accuracy of vaginal assessment of foetal head position.

TRIAL REGISTRATION

Registered at Chinese Clinical Trial Registry Platform (ChiCTR2200064783), October 17, 2022. https://www.chictr.org.cn/edit.aspx?pid=182857&htm=4.

The sonopartogram

The assessment of labor progress from digital vaginal examination has remained largely unchanged for at least a century, despite the current major advances in maternal and perinatal care. Although inconsistently reproducible, the findings from digital vaginal examination are customarily plotted manually on a partogram, which is composed of a graphical representation of labor, together with maternal and fetal observations. The partogram has been developed to aid recognition of failure to labor progress and guide management-specific obstetrical intervention. In the last decade, the use of ultrasound in the delivery room has increased with the advent of more powerful, portable ultrasound machines that have become more readily available for use. Although ultrasound in intrapartum practice is predominantly used for acute management, an ultrasound-based partogram, a sonopartogram, might represent an objective tool for the graphical representation of labor. Demonstrating greater accuracy for fetal head position and more objectivity in the assessment of fetal head station, it could be considered complementary to traditional clinical assessment. The development of the sonopartogram concept would require further undertaking of serial measurements. Advocates of ultrasound will concede that its use has yet to demonstrate a difference in obstetrical and neonatal morbidity in the context of the management of labor and delivery. Taking a step beyond the descriptive graphical representation of labor progress is the question of whether a specific combination of clinical and demographic parameters might be used to inform knowledge of labor outcomes. Intrapartum cesarean deliveries and deliveries assisted by forceps and vacuum are all associated with a heightened risk of maternal and perinatal adverse outcomes. Although these outcomes cannot be precisely predicted, many known risk factors exist. Malposition and high station of the fetal head, short maternal stature, and other factors, such as caput succedaneum, are all implicated in operative delivery; however, the contribution of individual parameters based on clinical and ultrasound assessments has not been quantified. Individualized risk prediction models, including maternal characteristics and ultrasound findings, are increasingly used in women's health-for example, in preeclampsia or trisomy screening. Similarly, intrapartum cesarean delivery models have been developed with good prognostic ability in specifically selected populations. For intrapartum ultrasound to be of prognostic value, robust, externally validated prediction models for labor outcome would inform delivery management and allow shared decision-making with parents.

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.

Intrapartum ultrasound use in clinical practice as a predictor of delivery mode during prolonged second stage of labor

PURPOSE

To determine the validity of intrapartum ultrasound (IPUS), and particularly the angle of progression (AOP), in predicting delivery mode when measured in real-life clinical practice among women with protracted second stages of labor.

METHODS

Using electronic medical records, nulliparous women with a second stage of labor of ≥ 3 h ("prolonged") and a documented AOP measurement during the second stage were identified. The ability of a single AOP measurement in "prolonged" second stage to predict a vaginal delivery (VD) was assessed. Fetal head descent, measured by AOP change/h (calculated from serial measurements), was compared between women who delivered vaginally and those who had a cesarean delivery (CD) for arrest of descent.

RESULTS

Of the 191 women who met the inclusion criteria, 62 (32.5%) delivered spontaneously, 96 (50.2%) had a vacuum extraction (VE) and 33 (17.3%) had a CD. The mean AOP was wider among women who had VD (spontaneous or VE) compared to those who had CD (153° ± 19 vs. 133° ± 17, p < 0.001). Wider AOPs were associated with higher rates of VD and an AOP ≥ 127° was associated with a VD rate of 88.6% (148/167). Among the 87 women who had more than one AOP measurement, the mean AOP change per hour was higher in the VD group than in the CD group (15.1° ± 11.4° vs. 6.2° ± 6.3°, p <  0.001).

CONCLUSION

Ultrasound-assessed fetal head station in nulliparous women with a protracted second stage of labor can be an accurate and objective additive tool in predicting the mode and interval time to delivery in real-life clinical practice.

Predictors of shoulder dystocia at the time of operative vaginal delivery: a prospective cohort study

Our aim was to identify factors associated with shoulder dystocia following an attempted operative vaginal delivery (aOVD) in a prospective cohort study and to evaluate whether these factors can be used to accurately predict shoulder dystocia by building a score of shoulder dystocia risk. This was a planned secondary analysis of a prospective cohort study of deliveries with aOVD at term from 2008-2013. Cases were defined as women with shoulder dystocia following an aOVD defined as a delivery that requires additional obstetric maneuvers following failure of gentle downward traction on the fetal head to effect delivery of the shoulders. Multivariate logistic regression analyses were performed to determine risk factors for shoulder dystocia. Shoulder dystocia occurred in 57 (2.7%) of the 2118 women included. In the whole cohort, women with shoulder dystocia more often had a history of shoulder dystocia (3.5% vs. 0.2%, p = 0.01), and there was a significant interaction between aOVD and gestational age and the duration of the second stage of labor: women with shoulder dystocia more often had a gestational age > 40 weeks and a second stage of labor longer than 3 h specifically for midpelvic aOVD. In multivariable analysis, a history of shoulder dystocia was the only factor independently associated with shoulder dystocia following aOVD (aOR 27.00, 95% CI 4.10-178.00). The AUC for the receiver operating characteristic curve generated using a multivariate model with term interaction with head station was 0.70 (95% CI 0.62-0.77). The model failed to accurately predict shoulder dystocia.

Prolonged Dystocic Labor in Neuraxial Analgesia and the Role of Enkephalin Neurotransmitters: An Experimental Study

The investigation studied the enkephalinergic neuro fibers (En) contained in the Lower Uterine Segment (LUS) during the prolonged dystocic labor (PDL) with Labor Neuraxial Analgesia (LNA). PDL is generally caused by fetal head malpositions in the Occiput Posterior Position (OPP), Persistent Occiput Posterior Position (POPP), in a transverse position (OTP), and asynclitism (A), and it is detected by Intrapartum Ultrasonography (IU). The En were detected in the LUS samples picked up during cesarean section (CS) of 38 patients undergoing urgent CS in PDL, compared to 37 patients submitted to elective CS. Results were statistically evaluated to understand the differences in En morphological analysis by scanning electron microscopy (SEM) and by fluorescence microscopy (FM). The LUS samples analysis showed an important reduction in En in LUS of CS for the PDL group, in comparison with the elective CS group. The LUS overdistension, by fetal head malpositions (OPP, OTP, A) and malrotations, lead to dystocia, modification of vascularization, and En reduction. The En reduction in PDL suggests that drugs used during the LNA, usually local anesthetics and opioids, cannot control the "dystocic pain", that differs from normal labor pain. The IU administration in labor and the consequent diagnosis of dystocia suggest stopping the numerous and ineffective top-up drug administration during LNA, and to shift the labor to operative vaginal delivery or CS.

Head-to-perineum distance measured transperineally as a predictor of failed midcavity vacuum-assisted delivery

BACKGROUND

During the second stage of labor, in case of a need for a fetal extraction at midcavity, the choice of attempting the procedure between operative vaginal delivery and cesarean delivery is difficult. Moreover, guidelines on this subject are not clear.

OBJECTIVE

This study aimed to identify antenatal and intrapartum parameters associated with a failed midcavity vacuum-assisted delivery and its association with maternal and neonatal adverse outcomes.

STUDY DESIGN

This was a single-center, retrospective, cohort study conducted at a tertiary maternity hospital in France from January 2010 to December 2020. Women with singleton pregnancies under epidural analgesia with nonanomalous cephalic presenting fetuses and gestational ages at ≥37 weeks of gestation, who were submitted to midcavity vacuum-assisted delivery, were included. Following the American College of Obstetricians and Gynecologists definition, midcavity was defined as the presenting part of the fetus (ie, the fetal head) found at stations 0 and +1. For research purposes, all patients were submitted to transperineal ultrasound to evaluate the head-to-perineum distance, however, this measurement did not affect the decision to perform a midcavity vacuum-assisted delivery. The primary outcome of the study was failed midcavity vacuum-assisted delivery leading to cesarean delivery or the use of a different instrument to achieve vaginal delivery.

RESULTS

Overall, 951 cases of midcavity vacuum-assisted delivery were included in this study. Failed midcavity vacuum-assisted delivery occurred in 242 patients (25.4%). Factors independently associated with failed midcavity vacuum-assisted delivery included maternal height (adjusted odds ratio, 0.96; 95% confidence interval, 0.94-0.99; P=.002), duration of the active phase of the first stage of labor (adjusted odds ratio, 1.11; 95% confidence interval, 1.05-1.17; P<.001), nonocciput anterior fetal head position (adjusted odds ratio, 1.47; 95% confidence interval, 1.06-2.04; P=.02), z score of the head-to-perineum distance (adjusted odds ratio, 1.23; 95% confidence interval, 1.05-1.43; P=.01), and birthweight of >4000 g (adjusted odds ratio, 2.04; 95% confidence interval, 1.28-3.26; P=.003). Women submitted to a failed midcavity vacuum-assisted delivery were more likely to have a major postpartum hemorrhage (7.1% vs 2.0%; P<.001), whereas neonates were more likely to have an umbilical artery pH of <7.1 (30.5% vs 19.8%; P=.001), be admitted to the neonatal intensive care unit (9.6% vs 4.7%; P=.005), and have a severe caput succedaneum (14.9% vs 0.7%; P<.001). Subgroup analysis on all patients with a fetal head station of 0 found that the head-to-perineum distance was the only independent variable associated with failed midcavity vacuum-assisted delivery (adjusted odds ratio, 1.66; 95% confidence interval, 1.29-2.12; P<.001). The area under the receiving operating characteristic curve of the head-to-perineum distance in this subgroup population was 0.67 (95% confidence interval, 0.60-0.73; P<.001), and the optimal cutoff point of the head-to-perineum distance measurement discriminating between failed and successful midcavity vacuum-assisted deliveries was 55 mm. It was associated with a 0.90 (95% confidence interval, 0.83-0.95) sensitivity, 0.19 (95% confidence interval, 0.14-0.25) specificity, 0.36 (95% confidence interval, 0.30-0.42) positive predictive value, and 0.80 (95% confidence interval, 0.66-0.90) negative predictive value.

CONCLUSION

Study data showed that a high fetal head station, measured using the head-to-perineum distance, and a nonocciput anterior position of the fetal head are independently associated with failed midcavity vacuum-assisted delivery. The result supported the systematic assessment of the sonographic head station and position before performing a midcavity vacuum-assisted delivery.

Preventing stillbirth from obstructed labor: A sensorized, low-cost device to train in safer operative birth

Background

98% of stillbirths occur in low- and middle- income countries. Obstructed labor is a common cause for both neonatal and maternal mortality, with a lack of skilled birth attendants one of the main reasons for the reduction in operative vaginal birth, especially in low- and middle- income countries. We introduce a low cost, sensorized, wearable device for digital vaginal examination to facilitate accurate assessment of fetal position and force applied to the fetal head, to aid training in safe operative vaginal birth.

Methods

The device consists of flexible pressure/force sensors mounted onto the fingertips of a surgical glove. Phantoms of the neonatal head were developed to replicate sutures. An Obstetrician tested the device on the phantoms by performing a mock vaginal examination at full dilatation. Data was recorded and signals interpreted. Software was developed so that the glove can be used with a simple smartphone app. A patient and public involvement panel was consulted on the glove design and functionality.

Results

The sensors achieved a 20 Newton force range and a 0.1 Newton sensitivity, leading to 100% accuracy in detecting fetal sutures, including when different degrees of molding or caput were present. They also detected sutures and force applied with a second sterile surgical glove on top. The software developed allowed a force threshold to be set, alerting the clinician when excessive force is applied. Patient and public involvement panels welcomed the device with great enthusiasm. Feedback indicated that women would accept, and prefer, clinicians to use the device if it could improve safety and reduce the number of vaginal examinations required.

Conclusion

Under phantom conditions to simulate the fetal head in labor, the novel sensorized glove can accurately determine fetal sutures and provide real-time force readings, to support safer clinical training and practice in operative birth. The glove is low cost (approximately 1 USD). Software is being developed so fetal position and force readings can be displayed on a mobile phone. Although substantial steps in clinical translation are required, the glove has the potential to support efforts to reduce the number of stillbirths and maternal deaths secondary to obstructed labor in low- and -middle income countries.

Can Intrapartum Ultrasonography Improve the Placement of the Vacuum Cup in Operative Vaginal Deliveries?

Although the fetal head position has traditionally been evaluated by digital examination (DE), it has a failure rate ranging between 20 and 70%; hence, intrapartum transabdominal ultrasonography (TUS) has become relevant. We aimed to evaluate the utility of the TUS to identify the fetal head positions in vacuum-assisted deliveries. We performed a prospective observational study including 101 pregnant patients in active labor who required a vacuum-assisted delivery. The fetal head position was assessed by a DE and a TUS prior to vacuum cup placement. After delivery, the optimal vacuum cup placement was evaluated as the distance between the chignon and the flexion point ≤2 cm. The general concordance rate between the DE and TUS was 72.2%, with the poorest concordance rate for occiput posterior positions at 46.1%. In five cases (4.9%), it was not possible to determine the fetal head position through the DE. The correlation was higher in low and medium planes, with 77% and 68.1% concordance rates, respectively, while it was lower in high planes (60%). In 90.1% of cases, the vacuum cup placement was optimal. Our findings show that intrapartum transabdominal ultrasonography is a useful technique to identify the fetal head position allowing optimal placement of the vacuum cup necessary for correct vacuum-assisted delivery.

Predictive value of head-perineum distance measured at the initiation of the active second stage of labor on the mode of delivery: A prospective cohort study

OBJECTIVE

The objective was to assess the predictive value of head-perineum distance measured at the initiation of the active second stage of labor on the mode of delivery.

MATERIAL AND METHODS

It was a prospective cohort study in an academic Hospital of Rennes, France, from July 1, 2020 to April 4, 2021 including 286 full-term parturients who gave birth to a newborn in cephalic presentation. A double-blind ultrasound measurement of the head-perineum distance was performed during the second phase of labor within five minutes after the onset of pushing efforts. The primary outcome was the mode of delivery (spontaneous vaginal delivery versus instrumental vaginal delivery or cesarean section). We performed a multivariate analysis to determine the predictive value of the head-perineum distance by adjusting on potential confounders.

RESULTS

Overall, 199 patients delivered by spontaneous vaginal delivery, 80 by instrumental vaginal delivery, and seven by cesarean section. The head-perineum distance measured at the beginning of pushing efforts was predictive of the mode of delivery with a threshold at 44 mm (crude: sensitivity = 56.8 % and specificity = 79.3 %; adjusted: sensitivity = 79.4 % and specificity = 87.4 %). The risk of medical intervention was higher when the head-perineum distance is>44 mm with an adjusted OR of 2.78 [1.38; 5.76].

CONCLUSION

The head-perineum distance measured at the initiation of the active second stage of labor is predictive of the mode of delivery. Head-perineum distance below 44 mm predicts a vaginal delivery with the best diagnostic performance, and optimizes the time to start pushing efforts.

The head direction to the angle of progression ratio: a quantitative parameter for intrapartum evaluation of cephalic malposition

BACKGROUND

No previous study has evaluated the transitions of intrapartum transperineal ultrasound parameters during labor progression in cephalic malposition.

OBJECTIVE

We aimed to quantitate the characteristic trends of fetal head position and descent in cephalic malposition by analyzing the transitions of intrapartum transperineal ultrasound parameters and explore an indicator associated with the degree of cephalic malposition.

STUDY DESIGN

We retrospectively analyzed pregnant women who delivered at term from January 2018 to December 2020 at the University of Tokyo Hospital. The fetal occipital position was classified as occiput anterior and nonocciput anterior according to the fetal occipital angle of 0° to 75° and 75° to 180°, respectively. Fetal occipital angle was defined by the midline angle and position of the ocular orbit. The differences in the trends of head direction, head-symphysis distance, and progression distance relative to the angle of progression between occiput anterior and nonocciput anterior cases were evaluated. In addition, the parameters that showed differences were analyzed to evaluate their relationship to the degree of cephalic malposition.

RESULTS

A total of 502 images (occiput anterior, 319; nonocciput anterior, 183) met the inclusion criteria. The distribution of head direction values relative to the angle of progression was smaller in the nonocciput anterior group than in the occiput anterior group, whereas the head-symphysis distance and progression distance values relative to the angle of progression showed no difference in their distribution between the occiput anterior and nonocciput anterior groups. The ratio of head direction to the angle of progression was significantly smaller in the nonocciput anterior group than in the occiput anterior group (median [interquartile range], 0.03 [-0.02 to 0.10] vs 0.21 [0.12-0.28]; P<.0001). Furthermore, this ratio was negatively correlated with fetal occipital angle (Spearman correlation coefficient, -0.66).

CONCLUSION

Our results indicated that the head direction to angle of progression ratio reflects the deviation in the fetal head direction toward the maternal dorsal side, and decreases in proportion to the degree of cephalic malposition. This concept of deviation in the head direction as an indicator for evaluating cephalic malposition with intrapartum transperineal ultrasound may contribute to improving labor management in the case of cephalic malposition.

How to Reach the Best Ultrasound Performance in the Delivery Room

Ultrasonography is an instrument that is present in the maternal-fetal assessment throughout pregnancy and with widely documented benefits, but its use in intrapartum is becoming increasingly relevant. From the assessment of labor progression to the assessment of placental disorders, ultrasound can be used to correlate with physiological findings and physical examination, as its benefit in the delivery room cannot yet be proven. There are still few professionals with adequate training for its use in the delivery room and for the correct interpretation of data. Thus, this article aims to present a review of the entire applicability of ultrasound in the delivery room, considering the main stages of labor. There is still limited research in evidence-based medicine of its various possible uses in intrapartum, but it is expected that further studies can bring improvements in the quality of maternal and neonatal health during labor.

Magnetic resonance imaging in late pregnancy to improve labour and delivery outcomes - a systematic literature review

BACKGROUND

Magnetic resonance imaging (MRI) provides excellent soft tissue visualisation which may be useful in late pregnancy to predict labour outcome and maternal/neonatal birth trauma.

OBJECTIVE

To study if MRI in late pregnancy can predict maternal and neonatal outcomes of labour and birth.

METHODS

Systematic review of studies that performed MRI in late pregnancy or immediately postpartum. Studies were included if they imaged maternal pelvic or neonatal structures and assessed birth outcome. Meta-analysis was not performed due to the heterogeneity of studies.

RESULTS

Eighteen studies were selected. Twelve studies explored the value of MRI pelvimetry measurement and its utility to predict cephalopelvic disproportion (CPD) and vaginal breech birth. Four explored cervical imaging in predicting time interval to birth. Two imaged women in active labour and assessed mouldability of the fetal skull. No marker of CPD had both high sensitivity and specificity for predicting labour outcome. The fetal pelvic index yielded sensitivities between 59 and 60%, and specificities between 34 to 64%. Similarly, although the sensitivity of the cephalopelvic disproportion index in predicting labour outcome was high (85%), specificity was only 56%. In women with breech presentation, MRI was demonstrated to reduce the rates of emergency caesarean section from 35 to 19%, and allowed better selection of vaginal breech birth. Live birth studies showed that the fetal head undergoes a substantial degree of moulding and deformation during cephalic vaginal birth, which is not considered during pelvimetry. There are conflicting studies on the role of MRI in cervical imaging and predicting time interval to birth.

CONCLUSION

MRI is a promising imaging modality to assess aspects of CPD, yet no current marker of CPD accurately predicts labour outcome. With advances in MRI, it is hoped that novel methods can be developed to better identify individuals at risk of obstructed or pathological labour. Its role in exploring fetal head moulding as a marker of CPD should be further explored.

Prediction of delivery after 40 weeks by antepartum ultrasound in singleton multiparous women: a prospective cohort study

OBJECTIVE

Universal elective induction of labor (IOL) in singleton parous pregnancies has been advocated to reduce the rate of cesarean section (CD), without impacting on maternal outcome. However, about 50% of women deliver after 40 weeks; therefore, an accurate estimation of the time of delivery might avoid unnecessary early IOL. The aim of this study was to test the diagnostic accuracy of ultrasound in predicting delivery ≥40 weeks of gestation in singleton parous women.

METHODS

Prospective cohort study of singleton parous women undergoing a dedicated ultrasound assessment at 36-38 weeks of gestation. The primary outcome was spontaneous vaginal delivery ≥40 weeks of gestation. Cervical length (CL), posterior cervical angle (PCA), sonoelastographic hardness ratio (HR), angle of progression (AoP) and head perineal distance (HPD) were measured. Multivariate logistic regression and area under the curve (AUC) analyses were used to test the diagnostic accuracy of different maternal and ultrasound characteristics in predicting delivery ≥40 weeks.

RESULTS

518 singleton pregnancies were included in the analysis and 235 (45.4%) delivered ≥40 weeks. CL (29 vs 19 mm; p ≤ .0001) and HPD (50 vs 47 mm; p = .001) were longer, HR higher (38.9 vs 35.5; p = .04), while PCA (98° vs 104°; p ≤ .0001) and AOP narrower (93° vs 98°; p = .029) in pregnancies delivered compared to those not delivered after 40 weeks of gestation. At multivariable logistic regression analysis, CL (aOR 1.206; 95% CI 1.164-1.250), HPD (aOR 1.127; 95% CI 1.066-1.191) and HR (aOR 1.022; 95% CI 1.003-1.041 were the only variables independently associated with delivery ≥40 weeks. CL showed had an AUC of 0.863 in predicting delivery ≥40 weeks of gestation, with an optimal cutoff of 23.5 mm. Integration of HPD and HR did not significantly improve the diagnostic performance of CL alone to predict delivery ≥40 weeks (AUC 0.870; p = .472).

CONCLUSION

Cervical length at 36-38 weeks has a good diagnostic accuracy to predict spontaneous vaginal delivery at ≥40 weeks. Universal assessment of CL in the third trimester of pregnancy may help in identifying those women who may benefit of elective IOL at 39 weeks.

Anatomical identification of ischial spines applicable to intrapartum transperineal ultrasound based on magnetic resonance imaging of pregnant women

OBJECTIVE

Intrapartum transperineal ultrasound is considered useful in judging fetal head descent; however, the inability to detect ischial spines on ultrasound images has been a drawback to its legitimacy. The current study aimed to determine the anatomical location of ischial spines, which can be directly applied to intrapartum transperineal ultrasound images.

METHOD

Based on magnetic resonance imaging (MRI) of 67 pregnant women at 33⁺² [31⁺⁶-34⁺⁰] weeks gestation (median [interquartile range: IQR]), we calculated the angle between the pubic symphysis and the midpoint of ischial spines (midline symphysis-ischial spine angle; mSIA), which is theoretically equivalent to the angle of progression at fetal head station 0 on ITU, by determining spatial coordinates of pelvic landmarks and utilizing spatial vector analysis. Furthermore, we measured symphysis-ischial spine distance (SID), defined as the distance between the vertical plane passing the lower edge of the pubic symphysis and the plane that passes the ischial spines.

RESULTS

As a result, mSIA was 109.6° [105.1-114.0] and SID 26.4 mm [19.8-30.7] (median, [IQR]). There was no correlation between mSIA or SID and maternal characteristics, including physique.

CONCLUSIONS

We established a novel method to measure the components of the pelvic anatomy by analyzing the three-dimensional coordinates of MRI data and identified the anatomical location of ischial spines which can be applied to ultrasound images. Our results provide valuable evidence to enhance the reliability of intrapartum transperineal ultrasound in assessing fetal head descent by considering the location of ischial spines.

The utilization of transperineal ultrasound following fetal heart deceleration after epidural analgesia: a case report

BACKGROUND

We report a case of fetal heart rate decelerations and relaxation of pelvic muscles and fetal descent using transperineal ultrasound after initiation of epidural labor analgesia.

CASE PRESENTATION

A 32-year-old woman, G1P0 with gestational age of 40 weeks, required epidural analgesia when her cervical dilatation was 2 cm. Baseline transperineal ultrasound examination was performed before epidural puncture. The fetal heart rate tracing was normal before the initiation of analgesia. Approximately 10 min after the epidural administration of the loading dose, the patient reported onset of analgesia and the FHR tracing showed variable-decelerations. There was no hypotension or evidence of uterine tachysystole. Transperineal ultrasound was performed again after epidural analgesia took effect. The anteroposterior diameter of the levator hiatus increased from 5.3 to 6.6 cm and angle of progress increased from 116°to 133°. The relaxation of pelvic muscle and rapid descent of fetal head may have contributed to the FHR deceleration. The midwife elevated the fetal head through the vagina with her hand, and the FHR recovered soon thereafter.

CONCLUSIONS

Changes in fetal heart rate after initiation of neuraxial analgesia are unpredictable. In addition to FHR and tocodynametric monitoring, performing TPU may helpful in distinguishing the reasons for FHR change and initiating corresponding corrective measures.

Vaginal Birth at Term - Part 1. Guideline of the DGGG, OEGGG and SGGG (S3-Level, AWMF Registry No. 015/083, December 2020)

Purpose This guideline aims to summarize the current state of knowledge about vaginal birth at term. The guideline focuses on definitions of the physiological stages of labor as well as differentiating between various pathological developments and conditions. It also assesses the need for intervention and the options to avoid interventions. This first part presents recommendations and statements about patient information and counselling, general patient care, monitoring of patients, pain management and quality control measures for vaginal birth. Methods The German recommendations largely reproduce the recommendations of the National Institute for Health and Care Excellence (NICE) CG 190 guideline "Intrapartum care for healthy women and babies". Other international guidelines were also consulted in specific cases when compiling this guideline. In addition, a systematic search and analysis of the literature was carried out using PICO questions, if this was considered necessary, and other systematic reviews and individual studies were taken into account. For easier comprehension, the assessment tools of the Scottish Intercollegiate Guidelines Network (SIGN) were used to evaluate the quality of the additionally consulted studies. Otherwise, the GRADE system was used for the NICE guideline and the evidence reports of the IQWiG were used to evaluate the quality of the evidence. Recommendations Recommendations and statements were formulated based on identified evidence and/or a structured consensus.

Vaginal Birth at Term - Part 2. Guideline of the DGGG, OEGGG and SGGG (S3-Level, AWMF Registry No. 015/083, December 2020)

Purpose This guideline aims to summarize the current state of knowledge about vaginal birth at term. The guideline focuses on definitions of the physiological stages of labor as well as differentiating between various pathological developments and conditions. It also assesses the need for intervention and the options to avoid interventions. The second part of this guideline presents recommendations and statements on care during the dilation and expulsion stages as well as during the placental/postnatal stage. Methods The German recommendations largely reproduce the recommendations of the National Institute for Health and Care Excellence (NICE) CG190 guideline "Intrapartum care for healthy women and babies". Other international guidelines were also consulted in individual cases when compiling this guideline. In addition, a systematic search and analysis of the literature was carried out using PICO questions where necessary, and other systematic reviews and individual studies were taken into account. For easier comprehension, the assessment tools of the Scottish Intercollegiate Guidelines Network (SIGN) were used to evaluate the quality of additionally consulted studies. Otherwise, the GRADE system was used for the NICE guideline, and the evidence reports of the IQWiG were used to evaluate the quality of the evidence. Recommendations Recommendations and statements were formulated based on identified evidence and/or a structured consensus.

Prediction of labor outcome pilot study: evaluation of primiparous women at term

BACKGROUND

Emergency operative delivery is associated with high fetal and maternal morbidity and mortality. It is of high importance to find means to predict the delivery mode before the onset of labor.

OBJECTIVE

This study aimed to investigate the potential of combined sonographic and clinical determination to predict the mode of delivery at term.

STUDY DESIGN

An observational prospective cohort study was deployed in a tertiary maternity hospital (Emergency County Hospital Craiova). Unselected low-risk primiparous pregnant women were evaluated weekly at term for ultrasound determinations (estimated fetal weight, head descent parameters, occiput posterior, cervical length), Bishop score, and maternal characteristics (age, height, weight). A thorough statistical analysis determined which variables were significantly correlated with the delivery mode.

RESULTS

Data from 276 term primiparous women were analyzed. Head descent parameters were strongly and significantly correlated with each other, but only progression distance was correlated with the delivery mode (gestational weeks 37, 38, 41, and the week before delivery). In the week before delivery, measurements of head-to-perineum distance and angle of progression reached almost significant P levels of.055 and.07, respectively. The following variables were significantly correlated with the delivery mode: body mass index in all term evaluations; progression distance for weeks 37 and 38; maternal age for week 39; Bishop score, estimated fetal weight, and occiput posterior for week 40; and body mass index, estimated fetal weight, and progression distance for the week before delivery. We also provided logistic regression equations for each week with correct delivery mode prediction, except for week 38. Cutoff values were established for each significant parameter per week. The cutoff values must be read in conjunction with the area under the curve, which ranged from 0.55 to 0.73, depending on the variable.

CONCLUSION

There are strong and significant correlations among the "head descent" ultrasound measurements at term. Body mass index is predictive of labor outcomes throughout term evaluations. Progression distance and body mass index measured at 37 to 38 weeks' gestation correlate with the delivery mode and apparently can be used to forecast the delivery mode when the pregnancy reaches term. For the week before delivery, measurements of estimated fetal weight and progression distance can be used to forecast the delivery mode, perhaps as part of a policy for pregnant women with prelabor clinical signs. Larger studies with more data, particularly better-balanced data, are needed.

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

This recommendation document follows the mission of the World Association of Perinatal Medicine in collaboration with the Perinatal Medicine Foundation. We aim to bring together groups and individuals throughout the world for standardization to implement the ultrasound evaluation in labor ward and improve the clinical management of labor. Ultrasound in labor can be performed using a transabdominal or a transperineal approach depending upon which parameters are being assessed. During transabdominal imaging, fetal anatomy, presentation, liquor volume, and placental localization can be determined. The transperineal images depict images of the fetal head in which calculations to determine a proposed fetal head station can be made.

Achieving an appropriate cesarean birth (CB) rate and analyzing the changes using the Robson Ten-Group Classification System (TGCS): Lessons from a Tertiary Care Hospital in Italy

BACKGROUND

To describe the interventions that were implemented at a Tertiary University Hospital and how they affected the rate of cesarean birth (CB) and main obstetrics and neonatal outcomes.

STUDY DESIGN

An analysis of the contemporaneously collected data from all deliveries that occurred from 2014 to 2018. Major obstetric and neonatal outcomes were analyzed and grouped according to the Ten-Group Classification System (TGCS).

RESULTS

A significant decrease in CB rates, from 28.4% to 23.0% (P < 0.001), was found over the study period. Although the relative sizes of both nulliparous (groups 1 + 2) and multiparous (groups 3 + 4) women remained stable over the study period, a significantly higher incidence of CB was reported in 2014 for both groups, compared with 2018 (2.6% vs. 13.0%, P < 0.001 for nulliparous women and 7.5% vs. 3.3%, P < 0.001 for multiparous women). In contrast, the relative size of Group 5 was significantly lower in 2014 than in 2018 (9.9% vs. 11.5%, P = 0.003), but a 13.3% reduction in CB was also reported for this group. No significant differences were noted in the occurrence of major obstetrics and neonatal outcomes that were reported.

CONCLUSIONS

A reduction in CB rate may be safely achieved through implementing a multifaceted strategy.

Accuracy of non-invasive methods for assessing the progress of labor in the first stage: a systematic review and meta-analysis

Background

The World Health Organization in recent years has emphasized reducing the possibility of unnecessary interventions in natural childbirth, but little is known about the accuracy of non-invasive methods when assessing the progress of labor. This paper presents a literature review to assess strategies that support non-invasive methods for labor during the first stage. It evaluates the available evidence to provide the most suitable assessments and predictions that objectively identify the progress of low-risk labor during the first stage of labor.

Methods

A search for relevant literature was conducted using the electronic databases of PubMed, CINAHL, Web of Sciences, the Cochrane Library, Scopus, Medline (OVID), and CEPS, with publications up to November 2021. Records were screened against pre-specified inclusion/exclusion criteria and the potential papers from Google Scholar were examined to identify additional papers that may have been missed. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool was used to appraise the methodological quality of the included studies. The certainty of the evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Two independent investigators extracted the review’s characteristics, and discrepancies were resolved by consensus. This review calculated individual and pooled sensitivity, specificity, and positive predictive values, which were exported to STATA (version 14; Stata Corp., College Station, TX) to represent the performance of diagnostic testing.

Results

Our search returned 2283 reports of which 13 fulfilled the inclusion criteria, accounting for 2594 women. The subjects were divided into groups according to the diagnostic tests used to assess the progress of their labor, including appearance assessment and sonographic imaging parameters (head perineum distance, HPD; angle of progression, AOP, and other parameters). HPD pooled sensitivity was 0.74 (0.65–0.82), and specificity was 0.77 (0.69–0.84). The pooled diagnostic odds ratio (DOR) was 8.21 (4.67–14.41) and 10.34 (5.02–21.27), respectively. The results of subgroup analysis showed that the summary sensitivity and specificity were of medium accuracy overall. The quality of evidence as assessed with GRADE was low.

Conclusion

Vaginal examination is an intrinsic element in the use of the partogram, while transperineal ultrasound can also be used as an auxiliary tool. However, the presence of publication bias within the parameters of ultrasound indicates that the diagnostic performance may be overestimated. Thus, randomized controlled trials or large-scale prospective cohort studies are necessary.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04938-y.

Sonographic evaluation of the fetal head position and attitude during labor

Fetal malpresentation, malposition, and asynclitism are among the most common determinants of a protracted active phase of labor, arrest of dilatation during the first stage, and arrest of descent in the second stage. The diagnosis of these conditions is traditionally based on vaginal examination, which is subjective and poorly reproducible. Intrapartum sonography has been demonstrated to yield higher accuracy than vaginal examination in characterizing fetal malposition, and some guidelines endorse its use for the verification of the occiput position before performing an instrumental delivery. It is also useful for the objective diagnosis of the malpresentation or asynclitism of the fetal head. According to our experience, the sonographic assessment of the head position in labor is simple to perform also for clinicians with basic ultrasound skills, whereas the assessment of malpresentation and asynclitism warrants a higher level of expertise. When clinically appropriate, the fetal occiput position can be easily ascertained using transabdominal sonography combining the axial and the sagittal planes. With the transducer positioned on the maternal suprapubic region, the fetal head can be visualized, and landmarks including the fetal orbits, the midline, and the occiput itself with the cerebellum and the cervical spine (depending on the type of fetal position) can be demonstrated below the probe. Sinciput, brow, and face represent the 3 "classical" variants of cephalic malpresentation and are characterized by a progressively increasing degree of deflexion from vertex presentation. Transabdominal sonography has been recently suggested for the objective assessment of the fetal head attitude when a cephalic malpresentation is clinically suspected. Fetal attitude can be evaluated on the sagittal plane with either a subjective or an objective approach. Two different sonographic parameters such as the occiput-spine angle and the chin-chest angle have been recently described to quantify the degree of flexion in fetuses in non-occiput-posterior or occiput-posterior position, respectively. Finally, although clinical examination still represents the mainstay of diagnosis of asynclitism, the use of intrapartum sonography has been shown to confirm the digital findings. The sonographic diagnosis of asynclitism can be achieved in expert hands using a combination of transabdominal and transperineal sonography. At suprapubic sonography on the axial plane only, 1 orbit can be visualized (squint sign) while the sagittal suture appears anteriorly (posterior asynclitism) or posteriorly (anterior asynclitism) displaced. Eventually the transperineal approach does not allow the visualization of the cerebral midline on the axial plane if the probe is perpendicular to the fourchette. In this expert review we summarize the indications, technique, and clinical role of intrapartum sonographic evaluation of fetal head position and attitude.

Manual rotation of occiput posterior or transverse positions: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

The primary objective of this systematic review was to assess the association between spontaneous vaginal delivery and manual rotation during labor for occiput posterior or transverse positions. Our secondary objective was to assess maternal and neonatal outcomes.

DATA SOURCES

An electronic search of PubMed, EMBASE, ClinicalTrials.gov, and the Cochrane Register of Controlled Trials covered the period from January 2000 to September 2021, without language restrictions.

STUDY ELIGIBILITY CRITERIA

The eligibility criteria included all randomized trials with singleton pregnancies at ≥37 weeks of gestation comparing the manual rotation groups with the control groups. The primary outcome was the rate of spontaneous vaginal delivery. Additional secondary outcomes were rate of occiput posterior position at delivery, operative vaginal delivery, cesarean delivery, postpartum hemorrhage, obstetrical anal sphincter injury, prolonged second stage of labor, shoulder dystocia, neonatal acidosis, and phototherapy. Subgroup analyses were performed according to types of position (occiput posterior or occiput transverse), techniques used (whole-hand or digital rotation), and parity (nulliparous or parous).

METHODS

The quality of each study was evaluated with the revised Cochrane risk-of-bias tool for randomized trials, known as RoB 2. The meta-analysis used random-effects models depending on their heterogeneity, and risks ratios were calculated for dichotomous outcomes.

RESULTS

Here, 7 of 384 studies met the inclusion criteria and were selected. They included 1402 women: 704 in the manual rotation groups and 698 in the control groups. Manual rotation was associated with a higher rate of spontaneous vaginal delivery: 64.9% vs 59.5% (risk ratio, 1.09; 95% confidence interval, 1.03-1.16; P=.005; 95% prediction interval, 0.90-1.32). This association was no longer significant after stratification by parity or technique used. Manual rotation was associated with spontaneous vaginal delivery only for the occiput posterior position (risk ratio, 1.08; 95% confidence interval, 1.01-1.15). Furthermore, it was associated with a reduction in occiput posterior or transverse positions at delivery (risk ratio, 0.64; 95% confidence interval, 0.48-0.87) and episiotomies (risk ratio, 0.84; 95% confidence interval, 0.71-0.98). The groups did not differ significantly for cesarean deliveries, operative vaginal deliveries, or neonatal outcomes.

CONCLUSION

Manual rotation increased the rate of spontaneous vaginal delivery.

Effects of Sex, Age and Height on Symphysis–Ischial Spine Distance Measured on a Pelvic CT

Objective: To examine the influence of age, sex and height on the symphysis–ischial spine distance (SID) measured on pelvic Computed tomography (CT)images in subjects of reproductive age, and to determine the interobserver reproducibility. This measurement (SID) is of great importance because the use of intrapartum ultrasound is based on the assumption of a specific value (30 mm) of such a measurement. Methods: This was a cross-sectional descriptive study in which SID was measured in subjects aged 20 to 44 years who had been scheduled for pelvic CT at our centre from January 2018 to May 2021 for different reasons. Radiographic measurements of the pelvis were obtained through the multiplanar reconstruction of the CT image. The images obtained from all of the participants were independently assessed by three senior radiologists, and the SID measurements made by each one were blinded from those of the remaining observers. Correlations between the SID and patient age, height and sex were analyzed by univariate and multivariate linear regression. Results: The mean SID for 87 of the enrolled participants (45 women, 42 men) was 28.2 ± 6.25 mm. Among the observers, the mean difference in this distance was 1 to 2 mm, and was scarcely related to measurement size, with agreement being greater than 70%. The mean SID was significantly related to sex and height (SID = −24.9 − 6.51 × sex (0 or 1) + 0.34 × height (cm); p = 0.01; sex equals 1 for a man and 0 for a woman), such that it was a mean of 2.5 mm greater in women than men (29.50 mm vs. 26.99 mm). Conclusion: Measurements of SID on CT images show good interobserver reproducibility, and are related to sex and height.

Uncertain fetal head engagement: a prospective randomized controlled trial comparing digital exam with angle of progression

BACKGROUND

Uncertain fetal head engagement represents 4% of obstetrical situations associated with an increased risk of postpartum hemorrhage, notably in cases of cesarean delivery and increased neonatal impairment owing to failed vaginal instrumental delivery. In this obstetrical condition, cesarean delivery is recommended, but vaginal delivery is possible in two-thirds of the cases. During the second stage of labor, the descent of the fetal head can be assessed by sonography, particularly by measuring the angle of progression.

OBJECTIVE

To evaluate, after a prolonged second stage of labor, the impact of measuring the angle of progression in addition to a digital examination on cesarean delivery rates when fetal head engagement remains uncertain.

STUDY DESIGN

This open multicenter randomized pragmatic trial included women at term with a singleton cephalic fetus in a clinical occiput anterior position after a prolonged 2-hour second stage of labor with uncertain fetal head engagement. After inclusion in the study, an independent investigator performed ultrasound systematically to confirm the occiput anterior position and measured the angle of progression at the climax of Valsalva pushing. This operator did not participate in labor management. In the study group but not in the control group, the angle of progression was communicated to the obstetrician in charge of labor management. Obstetricians were encouraged to attempt vaginal birth if the angle of progression was >120°. The primary outcome was the cesarean delivery rate. Secondary outcomes were operative delivery rate (cesarean delivery and operative vaginal delivery), maternal complications (third and fourth-degree perineal tears, failed vaginal instrumental delivery, postpartum hemorrhage, hysterectomy), and neonatal outcomes (Apgar score <5 at 10 minutes, umbilical arterial pH <7.10, neonatal wounds, neonatal intensive care unit admission).

RESULTS

A total of 45 women were included in the study. Occiput anterior position was confirmed in 33 women: 16 in the study group and 17 in the control group. Women's characteristics at baseline were similar between the groups. The median (range) angles of progression were similar: 138.4° (15) and 140.3° (16.9) in the study and control group, respectively. Cesarean delivery rates were 12.5% in the study group and 41.1% in the control group (P=.06). Secondary outcomes were similar between the 2 groups. No failed vaginal instrumental delivery was reported.

CONCLUSION

Measurement of the angle of progression in addition to digital examination when fetal head engagement remained uncertain showed promising results in decreasing cesarean delivery rates. A larger multicenter randomized controlled trial is needed to confirm these results.