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.

Prognostic accuracy of ultrasound measures of fetal head descent to predict outcome of operative vaginal birth: a comparative systematic review and meta-analysis.

OBJECTIVE: This study aimed to compare the prognostic accuracy of intrapartum transperineal ultrasound measures of fetal descent before operative vaginal birth in predicting complicated or failed procedures. DATA SOURCES: We performed a predefined systematic search in Medline, Embase, CINAHL, and Scopus from inception to June 10, 2022. STUDY ELIGIBILITY CRITERIA: We included studies assessing the following intrapartum transperineal ultrasound measures before operative vaginal birth to predict procedure outcome: angle of progression, head direction, head-perineum distance, head-symphysis distance, midline angle, and/or progression distance. METHODS: Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Bivariate meta-analysis was used to pool sensitivities and specificities into summary receiver operating characteristic curves for each intrapartum transperineal ultrasound measure. Subgroup analyses were performed for measures taken at rest vs with pushing and prediction of failed vs complicated operative vaginal birth. RESULTS: Overall, 16 studies involving 2848 women undergoing attempted operative vaginal birth were included. The prognostic accuracy of intrapartum transperineal ultrasound measures taken at rest to predict failed or complicated operative vaginal birth was high for angle of progression (area under the receiver operating characteristic curve, 0.891; 9 studies) and progression distance (area under the receiver operating characteristic curve, 0.901; 3 studies), moderate for head direction (area under the receiver operating characteristic curve, 0.791; 6 studies) and head-perineum distance (area under the receiver operating characteristic curve, 0.747; 8 studies), and fair for midline angle (area under the receiver operating characteristic curve, 0.642; 4 studies). There was no study with sufficient data to assess head-symphysis distance. Subgroup analysis showed that measures taken with pushing tended to have a higher area under the receiver operating characteristic curve for angle of progression (0.927; 4 studies), progression distance (0.930; 2 studies), and midline angle (0.903; 3 studies), with a similar area under the receiver operating characteristic curve for head direction (0.802; 4 studies). The prediction of failed vs complicated operative vaginal birth tended to be less accurate for angle of progression (0.837 [4 studies] vs 0.907 [6 studies]) and head direction (0.745 [3 studies] vs 0.810 [5 studies]), predominantly because of lower specificity, and was more accurate for head-perineum distance (0.812 [6 studies] vs 0.687 [2 studies]). CONCLUSION: Angle of progression, progression distance, and midline angle measured with pushing demonstrated the highest prognostic accuracy in predicting complicated or failed operative vaginal birth. Overall, the measurements seem to perform better with pushing than at rest.

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.

Novel artificial intelligence approach for automatic differentiation of fetal occiput anterior and non-occiput anterior positions during labor.

OBJECTIVES: To describe a newly developed machine-learning (ML) algorithm for the automatic recognition of fetal head position using transperineal ultrasound (TPU) during the second stage of labor and to describe its performance in differentiating between occiput anterior (OA) and non-OA positions. METHODS: This was a prospective cohort study including singleton term (> 37 weeks of gestation) pregnancies in the second stage of labor, with a non-anomalous fetus in cephalic presentation. Transabdominal ultrasound was performed to determine whether the fetal head position was OA or non-OA. For each case, one sonographic image of the fetal head was then acquired in an axial plane using TPU and saved for later offline analysis. Using the transabdominal sonographic diagnosis as the gold standard, a ML algorithm based on a pattern-recognition feed-forward neural network was trained on the TPU images to discriminate between OA and non-OA positions. In the training phase, the model tuned its parameters to approximate the training data (i.e. the training dataset) such that it would identify correctly the fetal head position, by exploiting geometric, morphological and intensity-based features of the images. In the testing phase, the algorithm was blinded to the occiput position as determined by transabdominal ultrasound. Using the test dataset, the ability of the ML algorithm to differentiate OA from non-OA fetal positions was assessed in terms of diagnostic accuracy. The F1 -score and precision-recall area under the curve (PR-AUC) were calculated to assess the algorithm's performance. Cohen's kappa (κ) was calculated to evaluate the agreement between the algorithm and the gold standard. RESULTS: Over a period of 24 months (February 2018 to January 2020), at 15 maternity hospitals affiliated to the International Study group on Labor ANd Delivery Sonography (ISLANDS), we enrolled into the study 1219 women in the second stage of labor. On the basis of transabdominal ultrasound, they were classified as OA (n = 801 (65.7%)) or non-OA (n = 418 (34.3%)). From the entire cohort (OA and non-OA), approximately 70% (n = 824) of the patients were assigned randomly to the training dataset and the rest (n = 395) were used as the test dataset. The ML-based algorithm correctly classified the fetal occiput position in 90.4% (357/395) of the test dataset, including 224/246 with OA (91.1%) and 133/149 with non-OA (89.3%) fetal head position. Evaluation of the algorithm's performance gave an F1 -score of 88.7% and a PR-AUC of 85.4%. The algorithm showed a balanced performance in the recognition of both OA and non-OA positions. The robustness of the algorithm was confirmed by high agreement with the gold standard (κ = 0.81; P < 0.0001). CONCLUSIONS: This newly developed ML-based algorithm for the automatic assessment of fetal head position using TPU can differentiate accurately, in most cases, between OA and non-OA positions in the second stage of labor. This algorithm has the potential to support not only obstetricians but also midwives and accoucheurs in the clinical use of TPU to determine fetal occiput position in the labor ward. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

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.

Usefulness of an Intrapartum Ultrasound Simulator (IUSim™) for Midwife Training: Results from an RCT.

INTRODUCTION: We conducted a randomized study to determine whether a training session on a dedicated simulator (IUSim™) would facilitate the midwives in learning the technique of transperineal intrapartum ultrasound. METHODS: Following a 30-min multimedia presentation including images and videos on how to obtain and measure the angle of progression (AoP) and the head-perineum distance (HPD), 6 midwives with no prior experience in intrapartum ultrasound were randomly split into 2 groups: 3 of them were assigned to the "training group" and 3 to the "control group." The midwives belonging to the former group were taught to measure the 2 sonographic parameters during a 3-h practical session conducted on IUSim™ under the supervision of an expert obstetrician. In the following 3 months, all the 6 midwives were asked to independently perform transperineal ultrasound during their clinical practice and to measure on the acquired images either the AoP or the HPD. The sonographic images were examined in blind by the teaching obstetrician who assigned a 0-3 score to the image quality (IQS) and to the measurement quality (MQS). RESULTS: A total of 48 ultrasound images (24 patients) from 5 midwives were acquired and included in the study analysis. A midwife of the "training group" declined participation after the practical session. Independently from the randomization group, the image quality score (IQS + MQS) was significantly higher for the HPD compared with the AoP (2.5 ± 0.66 vs. 1.79 ± 1.14; p = 0.01). In the training group, the MQS of either AoP (2.66 ± 0.5 vs.1.46 ± 1.45. p = 0.038) and the HPD (2.9 ± 0.33 vs. 1.87 ± 0.83 p = 0.002) was significantly higher in comparison with the control group, while the IQS of both measurements was comparable between the 2 groups (1.91 ± 1.24 vs. 2.25 ± 0.865; p = 0.28). CONCLUSION: The use of a dedicated simulator may facilitate the midwives in learning how to measure the AoP and the HPD on transperineal ultrasound images.

Comparison of different methods of measuring angle of progression in prediction of labor outcome.

OBJECTIVES: First, to compare the manual sagittal and parasagittal and automated parasagittal methods of measuring the angle of progression (AoP) by transperineal ultrasound during labor, and, second, to develop models for the prediction of time to delivery and need for Cesarean section (CS) for failure to progress (FTP) in a population of patients undergoing induction of labor. METHODS: This was a prospective observational study of transperineal ultrasound in a cohort of 512 women with a singleton pregnancy undergoing induction of labor. A random selection of 50 stored images was assessed for inter- and intraobserver reliability of AoP measurements using the manual sagittal and parasagittal and automated parasagittal methods. In cases of vaginal delivery, univariate linear, multiple linear and quantile regression analyses were performed to predict time to delivery. Univariate and multivariate binomial logistic regression analyses were performed to predict CS for FTP in the first stage of labor. RESULTS: The intraclass correlation coefficient (ICC) for the manual parasagittal method for a single observer was 0.97 (95% CI, 0.95-0.98) and for two observers it was 0.96 (95% CI, 0.93-0.98), indicating good reliability. The ICC for the sagittal method for a single observer was 0.93 (95% CI, 0.88-0.96) and for two observers it was 0.74 (95% CI, 0.58-0.84), indicating moderate reliability for a single observer and poor reliability between two observers. Bland-Altman analysis demonstrated narrower limits of agreement for the manual parasagittal approach than for the sagittal approach for both a single and two observers. The automated parasagittal method failed to capture an image in 19% of cases. The mean difference in AoP measurements between the sagittal and manual parasagittal methods was 11°. In pregnancies resulting in vaginal delivery, 54% of the variation in time to delivery was explained in a model combining parity, epidural and syntocinon use during labor and the sonographic findings of fetal head position and AoP. In the prediction of CS for FTP in the first stage of labor, a model which combined maternal factors with the sonographic measurements of AoP and estimated fetal weight was superior to one utilizing maternal factors alone (area under the receiver-operating-characteristics curve, 0.80 vs 0.76). CONCLUSIONS: First, the method of measuring AoP with the greatest reliability is the manual parasagittal technique and future research should focus on this technique. Second, over half of the variation in time to vaginal delivery can be explained by a model that combines maternal factors, pregnancy characteristics and ultrasound findings. Third, the ability of AoP to provide clinically useful prediction of CS for FTP in the first stage of labor is limited. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

New technique for automatic sonographic measurement of change in head-perineum distance and angle of progression during active phase of second stage of labor.

OBJECTIVE: To evaluate the performance of a new ultrasound technique for the automatic assessment of the change in head-perineum distance (delta-HPD) and angle of progression (delta-AoP) during the active phase of the second stage of labor. METHODS: This was a prospective observational cohort study including singleton term pregnancies with fetuses in cephalic presentation during the active phase of the second stage of labor. In each patient, two videoclips of 10 s each were acquired transperineally, one in the axial and one in the sagittal plane, between rest and the acme of an expulsive effort, in order to measure HPD and AoP, respectively. The videoclips were processed offline and the difference between the acme of the pushing effort and rest in HPD (delta-HPD) and AoP (delta-AoP) was calculated, first manually by an experienced sonographer and then using a new automatic technique. The reliability of the automatic algorithm was evaluated by comparing the automatic measurements with those obtained manually, which was considered as the reference gold standard. RESULTS: Overall, 27 women were included. A significant correlation was observed between the measurements obtained by the automatic and the manual methods for both delta-HPD (intraclass correlation coefficient (ICC) = 0.97) and delta-AoP (ICC = 0.99). The high accuracy provided by the automatic algorithm was confirmed by the high values of the coefficient of determination (r2 = 0.98 for both delta-HPD and delta-AoP) and the low residual errors (root mean square error = 1.2 mm for delta-HPD and 1.5° for delta-AoP). A Bland-Altman analysis showed a mean difference of 0.52 mm (limits of agreement, -1.58 to 2.62 mm) for delta-HPD (P = 0.034) and 0.35° (limits of agreement, -2.54 to 3.09°) for delta-AoP (P = 0.39) between the manual and automatic measurements. CONCLUSIONS: The automatic assessment of delta-AoP and delta-HPD during maternal pushing efforts is feasible. The automatic measurement of delta-AoP appears to be reliable when compared with the gold standard manual measurement by an experienced operator. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

How reliable is fetal occiput and spine position assessment prior to induction of labor?

OBJECTIVES: To assess the reliability of fetal occiput and spine position determination in nulliparous women prior to induction of labor (IOL), and to evaluate identification of fetal occiput and spine positions prior to IOL in the prediction of labor outcome. METHODS: A series of 136 nulliparous women were recruited prospectively, immediately after the decision to perform IOL was made. Transabdominal ultrasound was performed to determine fetal head and spine positions. After at least 1 h, and prior to IOL, fetal occiput and spine positions were reassessed. Fetal occiput and spine positions were then compared between women who underwent vaginal delivery and those who delivered by Cesarean section. RESULTS: On the first and second assessments, respectively, fetal occiput position was anterior in 55 (40.4%) and 62 (45.6%) women, transverse in 52 (38.2%) and 49 (36.0%) women, and posterior in 29 (21.3%) and 25 (18.4%) women, while fetal spine position was anterior in 58 (42.6%) and 52 (38.2%) women, transverse in 42 (30.9%) and 50 (36.8%) women, and posterior in 36 (26.5%) and 34 (25.0%) women. Discordance between the first and second assessments of fetal occiput position was identified in 34 (25.0%) women, whereas discordance of fetal spine position was observed in 40 (29.4%) women. The incidence of fetal occiput posterior position in women undergoing Cesarean section was comparable to that in the vaginal-delivery group (19 (18.8%) vs 6 (17.1%); P = 0.826), which was similarly the case for fetal posterior spine position (27 (26.7%) vs 7 (20%); P = 0.428). Women with fetal occiput posterior position had a longer induction-to-delivery interval in comparison to those with non-occiput posterior fetal position (1786 ± 805 vs 1347 ± 784 min; P = 0.013). CONCLUSIONS: Fetal occiput and spine positions are dynamic in a considerable proportion of women undergoing IOL, and their assessment does not seem to correlate with mode of delivery. Occiput and spine position assessment in women prior to IOL is unlikely to be clinically useful. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Use of intrapartum ultrasound in term pregnant women with contractions before hospital admission.

INTRODUCTION: The aim of this study was to test the hypothesis that transperineal ultrasound can be used to decide whether to admit a pregnant woman due to labor. MATERIAL AND METHODS: In this analytical cross-sectional observational study, transperineal ultrasound was performed on pregnant women with intact membranes who came to the hospital due to contractions. A decision was made to admit women due to labor based on the ultrasound measurements. The ultrasound measurements were used to determine cervical dilation, the angle of progression, and fetal head position. The managing midwives were blinded to the results and made the final decision to admit the women based on digital vaginal examination. RESULTS: It was possible to decide whether a woman had to be admitted for delivery or discharged due to the latent phase of labor according to the ultrasound examination in 55 of the 57 cases (96.5%). In four of the 55 cases, the decision based on ultrasound differed from the midwife's decision (7.3%). There was strong agreement between the decision to admit the pregnant women based on ultrasound measurements and the digital vaginal examination (Cohen's kappa: 0.844). It was possible to measure cervical dilation with ultrasound in 52 of the 57 cases (91.2%). The intraclass correlation coefficient for the cervical dilation measurements was 0.736 (95% confidence interval 0.539-0.848). CONCLUSIONS: There was strong agreement between the ultrasound and digital vaginal examination results in the decision to admit singleton pregnant women at term due to labor. A large number of vaginal examinations could be avoided by using intrapartum ultrasound.

Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.).

OBJECTIVE: To assess whether sonographic diagnosis of fetal head position before instrumental vaginal delivery can reduce the risk of failed vacuum extraction and improve delivery outcome. METHODS: Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.) is a randomized controlled trial of term (37 + 0 to 41 + 6 weeks' gestation) singleton pregnancies with cephalic presentation requiring instrumental delivery by vacuum extraction, which was conducted between April 2014 and June 2017 and involved 13 Italian maternity hospitals. Patients were randomized to assessment of fetal head position before attempted instrumental delivery by either vaginal examination (VE) alone or VE plus transabdominal sonography (TAS). Primary outcome was incidence of emergency Cesarean section due to failed vacuum extraction. A sample size of 653 women per group was planned to compare the primary outcome between the two groups. The sample size estimation was based on the hypothesis that the risk of failed vacuum delivery in the VE group would be 5% and that ultrasound assessment of fetal position prior to vacuum extraction would decrease this risk to 2%. RESULTS: On interim analysis, the trial was stopped for futility. During this period, 222 women were randomized and 221 were included in the final data analysis, of whom 132 (59.7%) were randomized to evaluation of fetal head position by VE only and 89 (40.3%) to assessment by VE plus TAS prior to vacuum extraction. No significant differences were observed between the two groups with respect to incidence of emergency Cesarean section due to failed instrumental delivery and other maternal and fetal outcomes. Women randomized to assessment by VE plus TAS showed higher incidence of non-occiput anterior position of the fetal head at randomization and lower incidence of incorrect diagnosis of occiput position compared with women undergoing assessment by VE alone. A higher rate of episiotomy was noted in the women undergoing both VE and TAS compared with those in the VE-only group. CONCLUSIONS: Our prematurely discontinued randomized controlled trial did not demonstrate any benefit in terms of reduced risk of failed instrumental delivery or maternal and fetal morbidity in women undergoing sonographic assessment of fetal head position prior to vacuum extraction. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Intra and interobserver variability of intrapartum transperineal ultrasound measurements with contraction and pushing.

The aim of this study was to evaluate the inter- and intraobserver correlation of the different intrapartum-transperineal-ultrasound-parameters(ITU) (angle of progression (AoP), progression-distance (PD), head-direction (HD), midline-angle (MLA) and head-perineum distance (HPD)) with contraction and pushing. We evaluated 28 nulliparous women at full dilatation under epidural analgesia. We performed a transperineal ultrasound evaluating AoP and PD in the longitudinal plane, and MLA and HPD in the transverse plane. Interclass correlation coefficients (ICC) with 95% CIs and Bland-Altman analysis were used to assess intra- and interobserver measurement's repeatability. The ICC of the ITU for the same observer was adequate for all the parameters (p < .005) AoP 0.98 (95%CI, 0.96-0.99), PD 0.98 (95%CI, 0.97-0.99), MLA 0.99 (95%CI, 0.97-0.99), HPD 0.96 (95%CI, 0.88-0.99). The ICC of the ITU for interobserver was: AoP 0.93 (95%CI, 0.79-0.98), PD 0.92 (95%CI, 0.76-0.97), MLA 0.77 (95%CI, 0.42-0.92), HPD 0.47 (95%CI, -0.12-0.8). The HD had an interobserver correlation of 0.53 (95%CI, 0.1-0.9) (Kappa C). The mean difference of the AoP was 2.42°, of the PD 1 mm and 0.28° MLA (Bland-Altman test). ITU has an adequate intra- and interobserver correlation for its use with contraction and pushing under epidural analgesia. Impact statement What is already known on this subject: The intrapartum transperineal ultrasound parameters can be used with contraction and pushing under epidural analgesia. What the results of this study add to what we know: ITU may be used to evaluate the difficulty of instrumental delivery/to evaluate the difficulty of instrumentation in vaginal operative deliveries and this study concludes that ITU is reproducible during uterine contraction with pushing. What the implications are of these findings for clinical practice and/or further research: Therefore, ITU could be used without difficulty with an adequate intra- and interobserver correlation for the prediction of instrumentation difficulty in operative vaginal deliveries.

Automatic ultrasound technique to measure angle of progression during labor.

OBJECTIVE: To evaluate the accuracy and reliability of an automatic ultrasound technique for assessment of the angle of progression (AoP) during labor. METHODS: Thirty-nine pregnant women in the second stage of labor, with fetus in cephalic presentation, underwent conventional labor management with additional translabial sonographic examination. AoP was measured in a total of 95 acquisition sessions, both automatically by an innovative algorithm and manually by an experienced sonographer, who was blinded to the algorithm outcome. The results obtained from the manual measurement were used as the reference against which the performance of the algorithm was assessed. In order to overcome the common difficulties encountered when visualizing by sonography the pubic symphysis, the AoP was measured by considering as the symphysis landmark its centroid rather than its distal point, thereby assuring high measurement reliability and reproducibility, while maintaining objectivity and accuracy in the evaluation of progression of labor. RESULTS: There was a strong and statistically significant correlation between AoP values measured by the algorithm and the reference values (r = 0.99, P < 0.001). The high accuracy provided by the automatic method was also highlighted by the corresponding high values of the coefficient of determination (r2 = 0.98) and the low residual errors (root mean square error = 2°27' (2.1%)). The global agreement between the two methods, assessed through Bland-Altman analysis, resulted in a negligible mean difference of 1°1' (limits of agreement, 4°29'). CONCLUSIONS: The proposed automatic algorithm is a reliable technique for measurement of the AoP. Its (relative) operator-independence has the potential to reduce human errors and speed up ultrasound acquisition time, which should facilitate management of women during labor. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Intrapartum transperineal ultrasound used to predict cases of complicated operative (vacuum and forceps) deliveries in nulliparous women.

INTRODUCTION: The objective of this study was to investigate the predictive value of intrapartum transperineal ultrasound in the identification of complicated operative (vacuum or forceps) deliveries in nulliparous women. MATERIAL AND METHODS: Prospective observational study of nulliparous women with an indication for operative delivery who underwent intrapartum transperineal ultrasound before fetal extraction. Managing obstetricians were blinded to the ultrasound data. Intrapartum transperineal ultrasound was performed immediately before blade application, both at rest and concurrently with contractions and active pushing. Operative delivery was classified as complicated when one or more of the following situations occurred: three or more tractions; a third-/fourth-degree perineal tear; significant bleeding during the episiotomy repair; major tear or significant traumatic neonatal lesion. RESULTS: A total of 143 nulliparous women were included in the study (82 vacuum-assisted deliveries and 61 forceps-assisted deliveries), with 20 fetuses in occiput posterior position. Forty-seven operative deliveries were classified as complicated deliveries (28 vacuum-assisted deliveries, 19 forceps-assisted deliveries). No differences in obstetric, intrapartum or neonatal characteristics were observed between the study groups, with the following exceptions: birthweight (3229 ± 482 uncomplicated deliveries vs. 3623 ± 406 complicated deliveries; p < 0.003) and number of vacuum tractions (1.4 uncomplicated deliveries, 4.5 complicated deliveries; p < 0.0005). The strongest predictors of a complicated delivery, using the area under the receiver-operating characteristics curve (AUC), were the angle of progression with active pushing (AoP2) (AUC 86.9%) and the progression distance with active pushing (PD2) (AUC 74.5%). The optimal cut-off value for predicting a difficult operative delivery was an AoP2 of 153.5° (sensitivity 95.2%; false-positive rate 5.9%) or PD2 of 58.5 mm (sensitivity 95.2%; false-positive rate 7.1%). CONCLUSIONS: The sonographic parameters AoP2 and PD2 can be used to predict cases of complicated operative deliveries in nulliparous women.

Automated Measurement of the Angle of Progression in Labor: A Feasibility and Reliability Study.

OBJECTIVES: The aim of this paper was to assess the feasibility and reliability of a new automated method for the measurement of the angle of progression (AoP) in labor. METHODS: AoP was assessed using two-dimensional transperineal ultrasound by two operators in 52 women in active labor to evaluate intra- and interobserver reproducibility. The intermethod agreement between automated and manual techniques was analyzed by means of the intraclass correlation coefficient and Bland-Altman method. RESULTS: Automated measurements were feasible in all cases. Automated assessments correctly depicted the pubic symphysis and fetal head in 133 (85.3%) out of 156 on first assessments and in all 156 after repeating measurements once in case of incorrect first evaluation. The automated technique showed good intra- and interobserver reproducibility and very good agreement with the manual technique. AoP measured by the automated method were significantly wider than those done by the manual technique (119 ± 20° vs. 130 ± 20°, p = 0.005). CONCLUSIONS: Automated assessment AoP is feasible and reproducible. However, measurements performed by the automated software are significantly different from those resulting from the previously published manual technique. In the light of our data, the automated technique does not seem ready yet for clinical use, and the AoP should be exclusively measured by the previously suggested manual technique.

The "occiput-spine angle": a new sonographic index of fetal head deflexion during the first stage of labor.

BACKGROUND: Fetal head "attitude" (relationship of fetal head to spine) in the first stage of labor may have a substantial impact on labor outcome. The diagnosis of fetal head deflexion traditionally is based on digital examination in labor, although the use of ultrasound to support clinical diagnosis has been recently reported. OBJECTIVES: The aims of this study were: (1) to quantify the degree of fetal head deflection via the use of sonography during the first stage of labor; and (2) to determine whether a parameter derived from ultrasound examination (the occiput-spine angle) has a relationship with the course and outcome of labor. STUDY DESIGN: This was a prospective multicentric, cross-sectional study conducted at the Maternity Unit of the University of Bologna and Parma from January 2014 to April 2015. A nonconsecutive series of women with uncomplicated singleton pregnancies at term gestation (37 weeks or more) were submitted to transabdominal ultrasound during the first stage of labor. If fetal position was occiput anterior or transverse, the angle between the fetal occiput and the cervical spine (the occiput-spine angle) was sonographically obtained on the sagittal plane. The measurements of the occiput spine-angle were performed offline by 2 operators who were blinded to the labor outcome. The intra- and interobserver reproducibility and the correlation between the occiput-spine angle and the mode of delivery were evaluated. RESULTS: A total of 108 pregnant women were recruited, 79 of which underwent a spontaneous vaginal delivery and 29 were submitted to obstetric intervention (19 cesarean delivery and 10 instrumental vaginal deliveries). The mean value of the occiput-spine angle measured in the active phase of the first stage was 126° ± 9.8° (SD). The occiput-spine angle measurement showed a very good intraobserver (r = 0.86; 95% confidence interval [95% CI] 0.80-0.90) and a fair-to-good interobserver (r = 0.64; 95% CI 0.51-0.74) agreement. The occiput-spine angle was significantly narrower in women who underwent obstetric intervention (cesarean or vacuum delivery) due to labor arrest (121° ± 10.5° vs 127° ± 9.4°, P = .03). Multivariable logistic regression analysis showed that narrow occiput-spine angle values (OR 1.08; 95% CI 1.00-1.16; P = .04) and nulliparity (OR 16.06; 95% CI 1.71-150.65; P = .02) were independent risk factors for operative delivery. A larger occiput-spine angle width (i.e., >125°) showed to be significantly associated with a shorter duration of labor (hazard ratio = 1.62; 95% CI 1.07-2.45; P = .02). CONCLUSION: We described herein the "occiput-spine angle," a new sonographic parameter to assess fetal head deflection during labor. Fetuses with smaller occiput-spine angle (<125°) are at increased risk for operative delivery.

Sonographic diagnosis of lateral asynclitism: a new subtype of fetal head malposition as a main determinant of early labor arrest.

We report on the sonographic appearance of a new type of fetal head malposition in labor that has not been previously described systematically. In some circumstances, the fetal lie is characterized by a lateral orientation of the head with respect to the trunk and, on suprapubic ultrasound, a transverse section of the fetal chest together with the facial profile can be seen on the same image. These sonographic findings were documented in five cases of first-stage labor arrest. This report illustrates how, in these circumstances, ultrasound might be helpful in clarifying the precise cause of obstructed labor.

Instrumental delivery and ultrasound : a multicentre randomised controlled trial of ultrasound assessment of the fetal head position versus standard care as an approach to prevent morbidity at instrumental delivery.

OBJECTIVE: To determine whether the use of ultrasound can reduce the incidence of incorrect diagnosis of the fetal head position at instrumental delivery and subsequent morbidity. DESIGN: Two-arm, parallel, randomised trial, conducted from June 2011 to December 2012. SETTING: Two maternity hospitals in the Republic of Ireland. SAMPLE: A cohort of 514 nulliparous women at term (≥37 weeks of gestation) with singleton cephalic pregnancies, aiming to deliver vaginally, were recruited prior to an induction of labour or in early labour. METHODS: If instrumental delivery was required, women who had provided written consent were randomised to receive clinical assessment (standard care) or ultrasound scan and clinical assessment (ultrasound). [Correction added on 17 April 2014, after first online publication: Sentence was amended.] MAIN OUTCOME MEASURE: Incorrect diagnosis of the fetal head position. RESULTS: The incidence of incorrect diagnosis was significantly lower in the ultrasound group than the standard care group (4/257, 1.6%, versus 52/257, 20.2%; odds ratio 0.06; 95% confidence interval 0.02-0.19; P < 0.001). The decision to delivery interval was similar in both groups (ultrasound mean 13.8 minutes, SD 8.7 minutes, versus standard care mean 14.6 minutes, SD 10.1 minutes, P = 0.35). The incidence of maternal and neonatal complications, failed instrumental delivery, and caesarean section was not significantly different between the two groups. CONCLUSIONS: An ultrasound assessment prior to instrumental delivery reduced the incidence of incorrect diagnosis of the fetal head position without delaying delivery, but did not prevent morbidity. A more integrated clinical skills-based approach is likely to be required to prevent adverse outcomes at instrumental delivery.

Sonographic pattern of fetal head descent: relationship with duration of active second stage of labor and occiput position at delivery.

OBJECTIVES: The objectives of this study were firstly to assess the longitudinal changes of various sonographic parameters of fetal head progression in relation to length of active second stage of labor, and secondly to compare ultrasound findings obtained longitudinally among fetuses with persistent occiput posterior (OP) vs those with persistent occiput anterior (OA) position. METHODS: From a series of nulliparous low-risk women at term attending the labor ward of our university hospital, transperineal ultrasound volumes were prospectively acquired at the beginning of the active second stage (T1) and at 40-min intervals thereafter until delivery (T2, T3). Sonographic parameters were derived from offline analysis of each volume, including the angle of progression (AoP), progression distance (PD), head-symphysis distance (HSD), head direction (HD) and midline angle. These parameters were compared between patients who delivered within 60 min from the beginning of the active second stage of labor (early delivery) and those who remained undelivered by that time (late delivery). Fetal head position was determined from stored digital images of transabdominal examinations performed at the beginning of the active second stage. Comparison was performed between fetuses with OA and those with persistent OP position at delivery. RESULTS: Spontaneous vaginal delivery was achieved in 58 (81.7%) cases, whereas vacuum extraction and Cesarean section were performed in eight (11.3%) and five (7.0%) cases, respectively. Delivery was achieved within 60 min from the beginning of the active second stage in 44 (62.0%) patients. In the early vs late delivery groups, measurements of AoP, HSD and PD at T1 were significantly different (AoP, 143.9 ± 20.5° vs 125.3 ± 15.0°, P < 0.001; HSD, 14.8 ± 4.5 mm vs 20.9 ± 5.8 mm, P < 0.001; PD, 44.0 ± 14.1 vs 35.0 ± 13.1 mm, P = 0.008). On logistic regression analysis of data obtained at T1, maternal body mass index, oxytocin administration, neonatal birth weight and HSD appeared to predict independently duration of the active second stage. Among fetuses delivering in the OP position (n = 10, 13.5%), Cesarean delivery was significantly more common than in those delivering in the OA position (n = 5 (50.0%) vs n = 2 (3.1%), P = 0.001). Women with persistent OP position compared with OA showed a significantly different AoP at T1 (122 ± 17° vs 138 ± 20°, P = 0.016), HD and HSD at T1 (HD, 112 ± 17 mm vs 86 ± 19 mm, P < 0.001; HSD, 16.5 ± 5.4 mm vs 22.8 ± 6.6 mm, P = 0.008) and at T2 (HD, 120 ± 16 vs 82 ± 27 mm, P = 0.008; HSD, 12.6 ± 3.4 mm vs 18.5 ± 5.4 mm, P = 0.038). CONCLUSIONS: AoP, PD and HSD are significantly different between patients undergoing delivery before or after 60 min from the beginning of the active second stage of labor. Ultrasound parameters are among the significant predictors of duration of the active second stage. Moreover, in fetuses persisting in the OP position vs those delivering in the OA position, fetal head progression seems to differ at early phases of the active second stage.

Use of intrapartum ultrasound in the prediction of complicated operative forceps delivery of fetuses in non-occiput posterior position.

OBJECTIVE: To evaluate the hypothesis that intrapartum ultrasound (ITU) measurements, including the angle of progression (AOP), progression distance (PD) and head direction (HD), can predict complicated forceps delivery in non-occiput posterior deliveries. METHODS: In this prospective observational study, a single operator performed ITU on 30 patients with an indication for operative forceps delivery. Managing obstetricians were blinded to the results. ITU was performed just before blade application, between contractions and concurrently with contractions and active pushing. Forceps delivery was classified as complicated when one or more of the following situations occurred: three or more tractions; a subjective impression of a difficult or failed application; a third-degree or higher perineal tear; significant bleeding during the episiotomy repair; major tear; significant traumatic neonatal lesion. RESULTS: Twenty-one forceps deliveries were classified as uncomplicated and nine were complicated. The strongest predictor of a complicated forceps delivery, calculated using the area under the receiver-operating characteristics curve (AUC), was the AOP between contractions (AOP1) (AUC = 98.9%). The best cut-off for predicting a difficult forceps delivery was an AOP1 of 138° (sensitivity = 85.7%, specificity = 100%). The best predictive model included both the AOP1 and the HD during a contraction with active pushing (HD2). CONCLUSION: The sonographic parameters AOP and HD can be used to predict complicated operative forceps delivery in fetuses in non-occiput posterior position.