Visual biofeedback for shortening second stage of labor: randomized controlled trial.

OBJECTIVE: To determine whether visual biofeedback can be used during labor as an effective tool for shortening the second stage of labor and reducing the need for instrumental delivery. METHODS: This was a single-center randomized controlled trial. Nulliparous women under epidural anesthesia were randomized at the point of full dilation into the biofeedback group (n = 50) or the control group (n = 50). Both groups received coached maternal pushing during four consecutive contractions, while an experienced obstetrician performed transperineal ultrasound. Only women in the biofeedback group observed the ultrasound display screen. Following this intervention, labor was managed routinely by the obstetric team. Angle of progression (AOP) was measured at rest and while pushing, before and during the first and fourth contractions. Second-stage duration and delivery outcomes were compared between groups. RESULTS: Visual biofeedback did not affect the duration of the second stage, which lasted for a median of 2.28 (interquartile range (IQR), 1.25-3.10) h in the biofeedback group vs 2.08 (IQR, 1.58-3.02) h in the control group (P = 0.981). AOP was significantly higher in the biofeedback group compared with the control group, both at rest before the fourth contraction (mean ± SD, 142.6° ± 15.9° vs 136.8° ± 13.1°; P = 0.049) and while pushing during the fourth contraction (mean ± SD, 159.3° ± 19.2° vs 149.4° ± 15.1°; P = 0.005). The increase in AOP was significantly higher in the biofeedback compared with the control group between rest and pushing at the last push (mean ± SD, 16.6° ± 11.0° vs 12.6° ± 8.3°; P = 0.041) and between the first rest and last push (mean ± SD, 24.4° ± 13.6° vs 17.9° ± 11.3°; P = 0.011). The rate of intact perineum was similar between groups (12% vs 8%; P = 0.505). CONCLUSIONS: Visual biofeedback during the second stage of labor may facilitate descent of fetal head during maternal pushing without affecting second-stage duration, possibly due to the short duration of the intervention. Future studies should focus on continuous intervention throughout the second stage of labor. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Implementation of sonopartogram: multicenter feasibility study.

OBJECTIVES: Well-established clinical practice for assessing progress in labor involves routine abdominal palpation and vaginal examination (VE). However, VE is subjective, poorly reproducible and painful for most women. In this study, our aim was to evaluate the feasibility of systematically integrating transabdominal and transperineal ultrasound assessment of fetal position, parasagittal angle of progression (psAOP), head-perineum distance (HPD) and sonographic cervical dilatation (SCD) to monitor the progress of labor in women undergoing induction of labor (IOL). We also aimed to determine if ultrasound can reduce women's pain during such examinations. METHODS: Women were recruited as they presented for IOL in three maternity units. Ultrasound assessments were performed in 100 women between 37 + 0 and 41 + 6 weeks' gestation. A baseline combined transabdominal and transperineal scan was performed, including assessment of fetal biometry, umbilical artery and fetal middle cerebral artery Doppler, amniotic fluid index, fetal spine and occiput positions, psAOP, HPD, SCD and cervical length. Intrapartum scans were performed instead of VE, unless there was a clinical indication to perform a VE, according to protocol. Participants were asked to indicate their level of pain by verbally giving a pain score between 0 and 10 (with 0 representing no pain) during assessment. Repeated measures data were analyzed using mixed-effect models to identify significant factors that affected the relationship between psAOP, HPD, SCD and mode of delivery. RESULTS: A total of 100 women were included in the study. Of these, 20% delivered by Cesarean section, 65% vaginally and 15% by instrumental delivery. There were no adverse fetal or maternal outcomes. A total of 223 intrapartum ultrasound scans were performed in 87 participants (13 women delivered before intrapartum ultrasound was performed), with a median of two scans per participant (interquartile range (IQR), 1-3). Of these, 76 women underwent a total of 151 VEs with a median of one VE per participant (IQR, 0-2), with no significant difference between vaginal- or Cesarean-delivery groups. After excluding those with epidural anesthesia during examination, the median pain score for intrapartum scans was 0 (IQR, 0-1) and for VE it was 3 (IQR, 0-6). Cesarean delivery was significantly associated with a slower rate of change in psAOP, HPD and SCD. CONCLUSIONS: Comprehensive transabdominal and transperineal ultrasound assessment can be used to assess progress in labor and can reduce the level of pain experienced during examination. Ultrasound assessment may be able to replace some transabdominal and vaginal examinations during labor. © 2024 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Predictive Value of Angle of Progression in Term Nulliparous Women: A Comprehensive Study on Spontaneous Vaginal Delivery Correlation and Clinical Implications.

OBJECTIVES: This study aims to explore the correlation between the angle of progression (AOP) and spontaneous vaginal delivery (SVD) for term nulliparous women before the onset of labor. Additionally, it evaluates the diagnostic efficacy of AOP in predicting SVD in term nulliparous women. METHODS: In this retrospective observational study, data from nulliparous women without contraindications for vaginal delivery, with a singleton pregnancy ≥37 weeks, and before the onset of labor were included. Transperineal ultrasound was performed to collect AOP. The date and mode of delivery were tracked, to assess the correlation between AOP and SVD in term nulliparous women. Receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic efficacy of AOP in predicting SVD for term nulliparous women. RESULTS: The SVD-failure (SVD-f) group exhibited a significantly lower AOP compared with the SVD group (88.43° vs 95.72°, P < .001). Logistic regression analysis revealed that AOP was associated with SVD in term nulliparous women (OR = 1.051). ROC curve analysis demonstrated that the area under the ROC curve with AOP 84° as the threshold was 0.663, with a sensitivity of 85.25% and specificity of 43.18%. Considering a sensitivity and specificity of 90%, the dual cut-off values for term nulliparous women for SVD were 81° and 104°, respectively. CONCLUSIONS: A positive correlation was identified between AOP and SVD for nulliparous women after 37 weeks and before the onset of labor. Notably, term nulliparous women with AOP exceeding 104° exhibited a higher probability of SVD.

Transperineal sonographic assessment of the angle of progression before the onset of labour: how well does it predict the mode of delivery in late-term pregnancy.

OBJECTIVES: Predicting the success of vaginal delivery is an important issue in preventing adverse maternal and neonatal outcomes. This study sought to examine whether measurement of the angle of progression (AoP) can predict a successful vaginal delivery following induction of labour (IoL) among late term nulliparous women with a low (4>) Bishop score. METHODS: This prospective study included consecutive nulliparous pregnant women whose gestational age was 41 weeks and 1-6 days (late-term). The AoP was measured at least three times and their means were calculated. RESULTS: During the study period, data of 150 women were included in the final analysis. Thirty-eight women underwent CS due to failure to progress (n=30) or NRGHR (n=8), while the remaining 112 women underwent NVD, with four women requiring vacuum extraction. The two groups were similar with respect to age, gestational age, BMI, estimated foetal weight, and birth weight. Women undergoing NVD differed significantly from those undergoing CS with respect to a greater ultrasonographic AoP (113.8±11.9° vs. 98.1±10.9°, p=0.0001), a shorter duration of dinoprostone use, shorter time to labour contraction, and a shorter duration of labour. In ROC analysis, the cut-off value for AoP was 100° for the prediction of successful IoL for NVD, with a sensitivity of 96 % and a specificity of 63 %. CONCLUSIONS: AoP may be a useful sonographic parameter for predicting successful vaginal delivery among nulliparous women at late term undergoing IoL; an AOP wider than 100° is associated with a high rate of vaginal delivery.

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.

The success of vaginal birth by use of trans-labial ultrasound plus vaginal examination and vaginal examination only in pregnant women with labor induction: a comparative study.

BACKGROUND: Predicting the success of vaginal delivery is an important issue in preventing adverse maternal and neonatal outcomes. Thus, this study aimed to compare the success rate of vaginal birth by using trans-labial ultrasound and vaginal examination, and vaginal examination only in pregnant women with labor induction. METHODS: This was a comparative study including 392 eligible pregnant women with labor induction attending to a teaching hospital affiliated with Iran University of Medical Sciences from April to October 2018 in Tehran, Iran. Women were randomly assigned to two groups; the trans-labial ultrasound plus vaginal examination (group A), and the vaginal examination only (group B). Women were included in the study if they satisfied the following criteria: singleton pregnancy, 37 to 42 weeks of gestational age, fetal head presentation, a living fetus with no abnormalities, uncomplicated pregnancy, and no previous cesarean section or any uterine surgery. We used a partograph for both groups to assess the fetal head position and the fetal head station. In group 1, the Angle of Progression (AoP) and Rotation Angle (RA) were also assessed. Finally, the success and progression of vaginal delivery in two groups were compared by predicting the duration of delivery and mode of delivery. RESULTS: The findings showed that 8.68% of women in the trans-labial plus vaginal examination group delivered by cesarean section, while 6.13% in the vaginal examination only group delivered by cesarean section (P = 0.55). In women with cesarean section in positive fetal head stations, Angle of Progression (AoP) was significantly decreased ranging from 90 to 135 degrees compared to women who delivered vaginally (135-180 degrees; P <  0.001). In addition, the Rotation Angle (RA) was significantly decreased in women with cesarean section ranging from 0 to 30 degrees compared to women who delivered vaginally (60-90degrees; P <  0.001). Further analysis indicated that a higher risk of cesarean section was associated with vaginal examination only as compared to trans-labial ultrasound plus vaginal examination (HR: 8.65, P <  0.001). CONCLUSION: Angle of Progression (AoP) and Rotation Angle (RA) indexes might be useful parameters to predict labor progression and successful vaginal delivery among women undergoing labor induction.

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.

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.

Intrapartum ultrasound measurement of angle of progression at the onset of the second stage of labor for prediction of spontaneous vaginal delivery in term singleton pregnancies: a systematic review and meta-analysis.

OBJECTIVE: This study aimed to investigate the diagnostic performance of transperineal ultrasound-measured angles of progression at the onset of the second stage of labor for the prediction of spontaneous vaginal delivery in singleton term pregnancies with cephalic presentation. DATA SOURCES: We performed a predefined systematic search in PubMed, Embase, Scopus, Web of Science, and Google Scholar from inception to February 5, 2021. STUDY ELIGIBILITY CRITERIA: Prospective cohort studies that evaluated the diagnostic performance of transperineal ultrasound-measured angles of progression (index test) at the onset of the second stage of labor (ie, when complete cervical dilation is diagnosed) for the prediction of spontaneous vaginal delivery (reference standard) were eligible for inclusion. Eligible studies were limited to those published as full-text articles in the English language and those that included only parturients with a singleton healthy fetus at term with cephalic presentation. STUDY APPRAISAL AND SYNTHESIS METHODS: Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Summary receiver operating characteristic curves, pooled sensitivities and specificities, area under the curve, and summary likelihood ratios were calculated using the Stata software. Subgroup analyses were done based on angle of progression ranges of 108° to 119°, 120° to 140°, and 141° to 153°. RESULTS: A total of 8 studies reporting on 887 pregnancies were included. Summary estimates of the sensitivity and specificity of transperineal ultrasound-measured angle of progression at the onset of the second stage of labor for predicting spontaneous vaginal delivery were 94% (95% confidence interval, 88%-97%) and 47% (95% confidence interval, 18%-78%), respectively, for an angle of progression of 108° to 119°, 81% (95% confidence interval, 70%-89%) and 73% (95% confidence interval, 57%-85%), respectively, for an angle of progression of 120° to 140°, and 66% (95% confidence interval, 56%-74%) and 82% (95% confidence interval, 66%-92%), respectively, for an angle of progression of 141° to 153°. Likelihood ratio syntheses gave overall positive likelihood ratios of 1.8 (95% confidence interval, 1-3.3), 3 (95% confidence interval, 2-4.7), and 3.7 (95% confidence interval, 1.7-8.1) and negative likelihood ratios of 0.13 (95% confidence interval, 0.07-0.22), 0.26 (95% confidence interval, 0.18-0.38), and 0.42 (95% confidence interval, 0.29-0.60) for angle of progression ranges of 108° to 119°, 120° to 140°, and 141° to 153°, respectively. CONCLUSION: Angle of progression measured by transperineal ultrasound at the onset of the second stage of labor may predict spontaneous vaginal delivery in singleton, term, cephalic presenting pregnancies and has the potential to be used along with physical examinations and other clinical factors in the management of labor and delivery.

Fetal head descent assessed by transabdominal ultrasound: a prospective observational study.

BACKGROUND: Determining fetal head descent, expressed as fetal head station and engagement is an essential part of monitoring progression in labor. Assessing fetal head station is based on the distal part of the fetal skull, whereas assessing engagement is based on the proximal part. Prerequisites for assisted vaginal birth are that the fetal head should be engaged and its lowermost part at or below the level of the ischial spines. The part of the fetal head above the pelvic inlet reflects the true descent of the largest diameter of the skull. In molded (reshaped) fetal heads, the leading bony part of the skull may be below the ischial spines while the largest diameter of the fetal skull still remains above the pelvic inlet. An attempt at assisted vaginal birth in such a situation would be associated with risks. Therefore, the vaginal or transperineal assessments of station should be supplemented with a transabdominal examination. We suggest a method for the assessment of fetal head descent with transabdominal ultrasound. OBJECTIVE: To investigate the correlation between transabdominal and transperineal assessment of fetal head descent, and to study fetal head shape at different labor stages and head positions. STUDY DESIGN: Women with term singleton cephalic pregnancies admitted to the labor ward for induction of labor or in spontaneous labor, at the Cairo University Hospital and Oslo University Hospital from December 2019 to December 2020 were included. Fetal head descent was assessed with transabdominal ultrasound as the suprapubic descent angle between a longitudinal line through the symphysis pubis and a line from the upper part of the symphysis pubis extending tangentially to the fetal skull. We compared measurements with transperineally assessed angle of progression and investigated interobserver agreement. We also measured the part of fetal head above and below the symphysis pubis at different labor stages. RESULTS: The study population comprised 123 women, of whom 19 (15%) were examined before induction of labor, 8 (7%) in the latent phase, 52 (42%) in the active first stage and 44 (36%) in the second stage. The suprapubic descent angle and the angle of progression could be measured in all cases. The correlation between the transabdominal and transperineal measurements was -0.90 (95% confidence interval, -0.86 to -0.93). Interobserver agreement was examined in 30 women and the intraclass correlation coefficient was 0.98 (95% confidence interval, 0.95-0.99). The limits of agreement were from -9.5 to 7.8 degrees. The fetal head was more elongated in occiput posterior position than in non-occiput posterior positions in the second stage of labor. CONCLUSION: We present a novel method of examining fetal head descent by assessing the proximal part of the fetal skull with transabdominal ultrasound. The correlation with transperineal ultrasound measurements was strong, especially early in labor. The fetal head was elongated in the occiput posterior position during the second stage of labor.

Angle of progression measured using transperineal ultrasound for prediction of uncomplicated operative vaginal delivery: systematic review and meta-analysis.

OBJECTIVE: To determine whether intrapartum transperineal ultrasound measurement of the angle of progression (AoP) during the second stage of labor can predict uncomplicated operative vaginal delivery (OVD) using vacuum or forceps extraction. METHODS: A systematic search in PubMed, EMBASE, Scopus, Web of Science and Google Scholar was performed from inception to February 2021. Studies assessing the predictive accuracy of AoP, measured using intrapartum transperineal ultrasound, for uncomplicated OVD, defined as successful vaginal delivery within three pulls using forceps or no more than two detachments of the vacuum extractor cup, were included. Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. Summary receiver-operating-characteristics (ROC) curves, pooled sensitivity and specificity, area under the ROC curve (AUC) and summary likelihood ratios (LRs) were calculated. RESULTS: Seven studies reporting on a total of 782 patients undergoing OVD were included in this systematic review and meta-analysis. Second-stage AoP measured during maternal rest had a pooled sensitivity of 80% (95% CI, 59-92%) and specificity of 89% (95% CI, 76-95%), with a LR+ of 7.3 (95% CI, 3.1-15.8) for uncomplicated OVD. AoP measured during active pushing had a sensitivity of 91% (95% CI, 85-94%) and specificity of 83% (95% CI, 69-92%), with a LR+ of 5.4 (95% CI, 2.7-10.6) for uncomplicated OVD. The performance of AoP measured at rest was particularly high in nulliparous women, with a sensitivity of 87% (95% CI, 75-94%) and specificity of 90% (95% CI, 82-94%) for uncomplicated OVD. CONCLUSION: AoP may be a reliable predictor for uncomplicated OVD when measured during the second stage of labor, especially in nulliparous women. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Sonographic risk assessment for an unplanned operative delivery: a prospective study.

PURPOSE: To assess the value of pre-labor maternal and fetal sonographic variables to predict an unplanned operative delivery. METHODS: In this prospective study, nulliparous women were recruited at 37.0-42.0 weeks of gestation. Sonographic measurements included estimated fetal weight, maternal pubic arch angle, and the angle of progression. We performed a descriptive and comparative analysis between two outcome groups: spontaneous vaginal delivery (SVD) and unplanned operative delivery (UOD) (vacuum-assisted, forceps-assisted and cesarean deliveries). Multivariate logistic regression with ROC analysis was used to create discriminatory models for UOD. RESULTS: Among 234 patients in the study group, 175 had a spontaneous vaginal delivery and 59 an unplanned operative delivery. Maternal height and pubic arch angle (PAA) significantly correlated with UOD. Analysis of Maximum Likelihood Estimates revealed a multivariate model for the prediction of UOD, including the parameters of maternal age, maternal height, sonographic PAA, angle of progression (AOP), and estimated fetal weight, with an area under the curve of 0.7118. CONCLUSION: Sonographic parameters representing maternal pelvic configuration (PAA) and maternal-fetal interface (AOP) improve the prediction ability of pre-labor models for a UOD. These data may aid the obstetrician in the counseling process before delivery.

The role of the angle of progression in the prediction of the outcome of occiput posterior position in the second stage of labor.

BACKGROUND: Occiput posterior position is the most frequent cephalic malposition, and its persistence at delivery is associated with a higher risk of maternal and perinatal morbidity. Diagnosis and management of occiput posterior position remain a clinical challenge. This is partly caused by our inability to predict fetuses who will spontaneously rotate into occiput anterior from those who will have persistent occiput posterior position. The angle of progression, measured with transperineal ultrasound, represents a reliable tool for the evaluation of fetal head station during labor. The relationship between the persistence of occiput posterior position and fetal head station in the second stage of labor has not been previously assessed. OBJECTIVE: This study aimed to evaluate the role of fetal head station, as measured by the angle of progression, in the prediction of persistent occiput posterior position and the mode of delivery in the second stage of labor. STUDY DESIGN: We recruited a nonconsecutive series of women with posterior occiput position diagnosed by transabdominal ultrasound in the second stage of labor. For each woman, a transperineal ultrasound was performed to measure the angle of progression at rest. We compared the angle of progression between women who delivered fetuses in occiput anterior position and those with persistent occiput posterior position at delivery. Receiver operating characteristics curves were performed to evaluate the accuracy of the angle of progression in the prediction of persistent occiput posterior position. Finally, we performed a multivariate logistic regression to determine independent predictors of persistent occiput posterior position. RESULTS: Overall, 63 women were included in the analysis. Among these, 39 women (62%) delivered in occiput anterior position, whereas 24 (38%) delivered in occiput posterior position (persistent occiput posterior position). The angle of progression was significantly narrower in the persistent occiput posterior position group than in women who delivered fetuses in occiput anterior position (118.3°±12.2° vs 127.5°±10.5°; P=.003). The area under the receiver operating characteristics curve was 0.731 (95% confidence interval, 0.594-0.869) with an estimated best cutoff range of 121.5° (sensitivity of 72% and specificity of 67%). On logistic regression analysis, the angle of progression was found to be independently associated with persistence of occiput posterior position (odds ratio, 0.942; 95% confidence interval, 0.889-0.998; P=.04). Finally, women who underwent cesarean delivery had significantly narrower angle of progression than women who had a vaginal delivery (113.5°±8.1 vs 128.0°±10.7; P<.001). The area under the receiver operating characteristics curve for the prediction of cesarean delivery was 0.866 (95% confidence interval, 0.761-0.972). At multivariable logistic regression analysis including the angle of progression, parity, and gestational age at delivery, the angle of progression was found to be the only independent predictor associated with cesarean delivery (odds ratio, 0.849; 95% confidence interval, 0.775-0.0930; P<.001). CONCLUSION: In fetuses with occiput posterior at the beginning of the second stage of labor, narrower values of the angle of progression are associated with higher rates of persistent occiput posterior position at delivery and a higher risk of cesarean delivery.

Fetal descent in nulliparous women assessed by ultrasound: a longitudinal study.

BACKGROUND: Ultrasound measurements offer objective and reproducible methods to measure the fetal head station. Before these methods can be applied to assess labor progression, the fetal head descent needs to be evaluated longitudinally in well-defined populations and compared with the existing data derived from clinical examinations. OBJECTIVE: This study aimed to use ultrasound measurements to describe the fetal head descent longitudinally as labor progressed through the active phase in nulliparous women with spontaneous onset of labor. STUDY DESIGN: This was a single center, prospective cohort study at the Landspitali - The National University Hospital of Iceland, Reykjavik, Iceland, from January 2016 to April 2018. Nulliparous women with a single fetus in cephalic presentation and spontaneous labor onset at a gestational age of ≥37 weeks, were eligible. Participant inclusion occurred during admission for women with an established active phase of labor or at the start of the active phase for women admitted during the latent phase. The active phase was defined as an effaced cervix dilated to at least 4 cm in women with regular contractions. According to the clinical protocol, vaginal examinations were done at entry and subsequently throughout labor, paired each time with a transperineal ultrasound examination by a separate examiner, with both examiners being blinded to the other's results. The measurements used to assess the fetal head station were the head-perineum distance and angle of progression. Cervical dilatation was examined clinically. RESULTS: The study population comprised 99 women. The labor patterns for the head-perineum distance, angle of progression, and cervical dilatation differentiated the participants into 75 with spontaneous deliveries, 16 with instrumental vaginal deliveries, and 8 cesarean deliveries. At the inclusion stage, the cervix was dilated 4 cm in 26 of the women, 5 cm in 30 of the women, and ≥6 cm in 43 women. One cesarean and 1 ventouse delivery were performed for fetal distress, whereas the remaining cesarean deliveries were conducted because of a failure to progress. The total number of examinations conducted throughout the study was 345, with an average of 3.6 per woman. The ultrasound-measured fetal head station both at the first and last examination were associated with the delivery mode and remaining time of labor. In spontaneous deliveries, rapid head descent started around 4 hours before birth, the descent being more gradual in instrumental deliveries and absent in cesarean deliveries. A head-perineum distance of 30 mm and angle of progression of 125° separately predicted delivery within 3.0 hours (95% confidence interval, 2.5-3.8 hours and 2.4-3.7 hours, respectively) in women delivering vaginally. Although the head-perineum distance and angle of progression are independent methods, both methods gave similar mirror image patterns. The fetal head station at the first examination was highest for the fetuses in occiput posterior position, but the pattern of rapid descent was similar for all initial positions in spontaneously delivering women. Oxytocin augmentation was used in 41% of women; in these labors a slower descent was noted. Descent was only slightly slower in the 62% of women who received epidural analgesia. A nonlinear relationship was observed between the fetal head station and dilatation. CONCLUSION: We have established the ultrasound-measured descent patterns for nulliparous women in spontaneous labor. The patterns resemble previously published patterns based on clinical vaginal examinations. The ultrasound-measured fetal head station was associated with the delivery mode and remaining time of labor.

When does fetal head rotation occur in spontaneous labor at term: results of an ultrasound-based longitudinal study in nulliparous women.

BACKGROUND: Improved information about the evolution of fetal head rotation during labor is required. Ultrasound methods have the potential to provide reliable new knowledge about fetal head position. OBJECTIVE: The aim of the study was to describe fetal head rotation in women in spontaneous labor at term using ultrasound longitudinally throughout the active phase. STUDY DESIGN: This was a single center, prospective cohort study at Landspitali - The National University Hospital of Iceland, Reykjavík, Iceland, from January 2016 to April 2018. Nulliparous women with a single fetus in cephalic presentation and spontaneous labor onset at ≥37 weeks' gestation were eligible. Inclusion occurred when the active phase could be clinically established by labor ward staff. Cervical dilatation was clinically examined. Fetal head position and subsequent rotation were determined using both transabdominal and transperineal ultrasound. Occiput positions were marked on a clockface graph with 24 half-hour divisions and categorized into occiput anterior (≥10- and ≤2-o'clock positions), left occiput transverse (>2- and <4-o'clock positions), occiput posterior (≥4- and ≤8 o'clock positions), and right occiput transverse positions (>8- and <10-o'clock positions). Head descent was measured with ultrasound as head-perineum distance and angle of progression. Clinical vaginal and ultrasound examinations were performed by separate examiners not revealing the results to each other. RESULTS: We followed the fetal head rotation relative to the initial position in the pelvis in 99 women, of whom 75 delivered spontaneously, 16 with instrumental assistance, and 8 needed cesarean delivery. At inclusion, the cervix was dilated 4 cm in 26 women, 5 cm in 30 women, and ≥6 cm in 43 women. Furthermore, 4 women were examined once, 93 women twice, 60 women 3 times, 47 women 4 times, 20 women 5 times, 15 women 6 times, and 3 women 8 times. Occiput posterior was the most frequent position at the first examination (52 of 99), but of those classified as posterior, most were at 4- or 8-o'clock position. Occiput posterior positions persisted in >50% of cases throughout the first stage of labor but were anterior in 53 of 80 women (66%) examined by and after full dilatation. The occiput position was anterior in 75% of cases at a head-perineum distance of ≤30 mm and in 73% of cases at an angle of progression of ≥125° (corresponding to a clinical station of +1). All initial occiput anterior (19), 77% of occiput posterior (40 of 52), and 93% of occiput transverse positions (26 of 28) were thereafter delivered in an occiput anterior position. In 6 cases, the fetal head had rotated over the 6-o'clock position from an occiput posterior or transverse position, resulting in a rotation of >180°. In addition, 6 of the 8 women ending with cesarean delivery had the fetus in occiput posterior position throughout the active phase of labor. CONCLUSION: We investigated the rotation of the fetal head in the active phase of labor in nulliparous women in spontaneous labor at term, using ultrasound to provide accurate and objective results. The occiput posterior position was the most common fetal position throughout the active phase of the first stage of labor. Occiput anterior only became the most frequent position at full dilatation and after the head had descended below the midpelvic plane.

Predicting cesarean delivery for failure to progress as an outcome of labor induction in term singleton pregnancy.

BACKGROUND: Induction of labor is one of the most common interventions in modern obstetrics, and its frequency is expected to continue to increase. There is inconsistency as to how failed induction of labor is defined; however, the majority of studies define success as the achievement of vaginal delivery. Induction of labor in nulliparous women poses an additional challenge with a 15% to 20% incidence of failure, ending in emergency operative deliveries. The Bishop score has been traditionally used before decisions for induction of labor. Nonetheless, it is subjective and prone to marked interobserver variation. Several studies have been conducted to find alternative predictors, yet a reliable, objective method still remains to be introduced and validated. Hence, there is still a need for the development of new predictive tools to facilitate informed decision making, optimization of resources, and minimization of potential risks of failure. Furthermore, a peripartum transperineal ultrasound scan has been proven to provide objective, noninvasive assessment of labor. OBJECTIVE: This study aimed to assess the feasibility of developing and validating an objective and reproducible model for the prediction of cesarean delivery for failure to progress as an outcome of labor induction in term singleton pregnancies. STUDY DESIGN: This was a prospective observational cohort study conducted in Cairo University Hospitals and University of Bologna Hospitals between November 2018 and November 2019. We recruited 382 primigravidae with singleton term pregnancies in cephalic presentation. All patients had baseline Bishop scoring together with various transabdominal and transperineal ultrasound assessments of the fetus, maternal cervix, and pelvic floor. The managing obstetricians were blinded to the ultrasound scan findings. The method and indication of induction of labor, the total duration of stages of labor, mode of birth, and neonatal outcomes were all recorded. Women who had operative delivery for fetal distress or indications other than failure to progress in labor were excluded from the final analysis, leaving a total of 344 participants who were randomly divided into 243 and 101 pregnancies that constituted the model development and cross-validation groups, respectively. RESULTS: It was possible to perform transabdominal and transperineal scans and assess all the required parameters on all study participants. Univariate and multivariate analyses were used for selection of potential predictors and model fitting. The independent predictive variables for cesarean delivery included maternal age (odds ratio, 1.12; P=.003), cervical length (odds ratio, 1.08; P=.04), angle of progression at rest (odds ratio, 0.9; P=.001), and occiput posterior position (odds ratio, 5.7; P=.006). We tested the performance of the prediction model on our cross-validation group. The calculated areas under the curve for the ability of the model to predict cesarean delivery were 0.7969 (95% confidence interval, 0.71-0.87) and 0.88 (95% confidence interval, 0.79-0.97) for the developed and validated models, respectively. CONCLUSION: Maternal age and sonographic fetal occiput position, angle of progression at rest, and cervical length before labor induction are very good predictors of induction outcome in nulliparous women at term.

Umbilical cord prolapse: revisiting its definition and management.

Umbilical cord prolapse is an unpredictable obstetrical emergency with an incidence ranging from 1 to 6 per 1000 pregnancies. It is associated with high perinatal mortality, ranging from 23% to 27% in low-income countries to 6% to 10% in high-income countries. In this review, we specifically addressed 3 issues. First, its definition is not consistent in the current literature, and "occult cord prolapse" is a misnomer because the cord is still above the cervix. We proposed that cord prolapse, cord presentation, and compound cord presentation should be classified according to the positional relationship among the cord, the fetal presenting part, and the cervix. All of them may occur with either ruptured or intact membranes. The fetal risk is highest in cord prolapse, followed by cord presentation, and lastly by compound cord presentation, which replaces the misnomer "occult cord prolapse." Second, the mainstay of treatment of cord prolapse is urgent delivery, which means cesarean delivery in most cases, unless vaginal delivery is imminent. The urgency depends on the fetal heart rate pattern, which can be bradycardia, recurrent decelerations, or normal. It is most urgent in cases with bradycardia, because a recent study showed that cord arterial pH declines significantly with the bradycardia-to-delivery interval at a rate of 0.009 per minute (95% confident interval, 0.0003-0.0180), and this may indicate an irreversible pathology such as vasospasm or persistent cord compression. However, cord arterial pH does not correlate with either deceleration-to-delivery interval or decision-to-delivery interval, indicating that intermittent cord compression causing decelerations is reversible and less risk. Third, while cesarean delivery is being arranged, different maneuvers should be adopted to relieve cord compression by elevating the fetal presenting part and to prevent further cord prolapse beyond the vagina. A recent study showed that the knee-chest position provides the greatest elevation effect, followed by filling of the maternal urinary bladder with 500 mL of fluid, and then the Trendelenburg position (15°) and other maneuvers. However, each maneuver has its own advantages and limitations; thus, they should be applied wisely and with great caution, depending on the actual clinical situation. Therefore, we have proposed an algorithm to guide this acute management.

Intrapartum sonographic assessment of the fetal head flexion in protracted active phase of labor and association with labor outcome: a multicenter, prospective study.

BACKGROUND: To date, no research has focused on the sonographic quantification of the degree of flexion of the fetal head in relation to the labor outcome in women with protracted active phase of labor. OBJECTIVE: This study aimed to assess the relationship between the transabdominal sonographic indices of fetal head flexion and the mode of delivery in women with protracted active phase of labor. STUDY DESIGN: Prospective evaluation of women with protracted active phase of labor recruited across 3 tertiary maternity units. Eligible cases were submitted to transabdominal ultrasound for the evaluation of the fetal head position and flexion, which was measured by means of the occiput-spine angle in fetuses in nonocciput posterior position and by means of the chin-to-chest angle in fetuses in occiput posterior position. The occiput-spine angle and the chin-to-chest angle were compared between women who had vaginal delivery and those who had cesarean delivery. Cases where obstetrical intervention was performed solely based on suspected fetal distress were excluded. RESULTS: A total of 129 women were included, of whom 43 (33.3%) had occiput posterior position. Spontaneous vaginal delivery, instrumental delivery, and cesarean delivery were recorded in 66 (51.2%), 17 (13.1%), and 46 (35.7%) cases, respectively. A wider occiput-spine angle was measured in women who had vaginal delivery compared with those submitted to cesarean delivery owing to labor dystocia (126±14 vs 115±24; P<.01). At the receiver operating characteristic curve, the area under the curve was 0.675 (95% confidence interval, 0.538-0.812; P<.01), and the optimal occiput-spine angle cutoff value discriminating between cases of vaginal delivery and those delivered by cesarean delivery was 109°. A narrower chin-to-chest angle was measured in cases who had vaginal delivery compared with those undergoing cesarean delivery (27±33 vs 56±28 degrees; P<.01). The area under the curve of the chin-to-chest angle in relation to the mode of delivery was 0.758 (95% confidence interval, 0.612-0.904; P<.01), and the optimal cutoff value discriminating between vaginal delivery and cesarean delivery was 33.0°. CONCLUSION: In women with protracted active phase of labor, the sonographic demonstration of fetal head deflexion in occiput posterior and in nonocciput posterior fetuses is associated with an increased incidence of cesarean delivery owing to labor dystocia. Such findings suggest that intrapartum ultrasound may contribute in the categorization of the etiology of labor dystocia.

Fetal head progression and regression on maternal pushing at term and labor outcome.

OBJECTIVES: The aim of our study was two-fold. First, to evaluate the association between the change in the angle of progression (AoP) on maternal pushing and labor outcome. Second, to assess the incidence and clinical significance of the reduction of AoP on maternal pushing. METHODS: This was a prospective cohort study of nulliparous women with singleton pregnancy at term. AoP was measured at rest and on maximum Valsalva maneuver before the onset of labor, and the difference between AoP on maximum Valsalva and that at rest (ΔAoP) was calculated for each woman. Following delivery and data collection, we assessed the association between ΔAoP and various labor outcomes, including Cesarean section (CS), duration of the first, second and active second stages of labor, Apgar score and admission to the neonatal intensive care unit (NICU). The prevalence of women with reduction of AoP on maximum Valsalva maneuver (AoP-regression group) was calculated and its association with the mode of delivery and duration of different stages of labor was assessed. RESULTS: Overall, 469 women were included in the analysis. Among these, 273 (58.2%) had spontaneous vaginal birth, 65 (13.9%) had instrumental delivery and 131 (27.9%) underwent CS. Women in the CS group were older, had narrower AoP at rest and on maximum Valsalva, higher rate of epidural administration and lower 1-min and 5-min Apgar scores in comparison with the vaginal-delivery group. ΔAoP was comparable between the two groups. On Pearson's correlation analysis, AoP at rest and on maximum Valsalva maneuver had a significant negative correlation with the duration of the first stage of labor. ΔAoP showed a significant negative correlation with the duration of the active second stage of labor (Pearson's r, -0.125; P = 0.02). Cox regression model analysis showed that ΔAoP was associated independently with the duration of the active second stage (hazard ratio, 1.014 (95% CI, 1.003-1.025); P = 0.012) after adjusting for maternal age and body mass index. AoP reduction on maximum Valsalva was found in 73 (15.6%) women. In comparison with women who showed no change or an increase in AoP on maximum Valsalva, the AoP-regression group did not demonstrate significant difference in maternal characteristics, mode of delivery, rate of epidural analgesia, duration of the different stages of labor or rate of NICU admission. CONCLUSIONS: In nulliparous women at term before the onset of labor, narrower AoP at rest and on maximum Valsalva, reflecting fetal head engagement, is associated with a higher risk of Cesarean delivery. The increase in AoP from rest to Valsalva, reflecting more efficient maternal pushing, is associated with a shorter active second stage of labor. Fetal head regression on maternal pushing is present in about 16% of women and does not appear to have clinical significance. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.