Antepartum ultrasound prediction of failed vacuum-assisted operative delivery: a prospective cohort study

Angle of progression for predicting second-stage cesarean delivery complications

OBJECTIVE

To investigate the correlation between the angle of progression (AOP) and maternal surgical complications following a second-stage cesarean delivery.

METHODS

We retrospectively evaluated singleton pregnancies at term (≥37 weeks) who underwent cesarean delivery for arrest of descent at the second stage of labor from January 2022 to December 2023. Only cases with recorded AOP were included. The fetal head position was confirmed by transabdominal ultrasound, and the fetal head station was assessed manually by digital examination. The main outcome was defined as a composite adverse maternal outcome, including challenging fetal extraction, uterine extension, requirement for blood transfusions, postpartum fever, ileus, and re-hospitalization due to endometritis or surgical site infection.

RESULTS

Twenty-five cases met the inclusion criteria, of whom 10 (40%) experienced the composite adverse maternal outcome. These patients had wider mean AOP compared to those without maternal morbidity (136.7 ± 7.4 vs. 124.7 ± 12.5, p = .017). Univariate logistic regression analysis showed a significant correlation between measured AOP and composite adverse maternal outcome (OR = 1.15, 95% CI 1.01-1.30, p = .028). The predicted probability for composite adverse maternal outcome by receiver-operating characteristics curve yielded an area under the curve of 0.79 (95% CI 0.60-0.98) for AOP, compared to an area under the curve of 0.53 (95% CI 0.30-0.75) for the manually measured fetal head station.

CONCLUSIONS

We found a correlation between the angle of progression and maternal complications following second-stage cesarean delivery. Assessing the angle of progression before surgery may be of help to the obstetrical team to better identify susceptible cases and allow for appropriate preparation.

Sex-specific bone and muscular morphological features in ischiofemoral impingement: A three-dimensional study

The study aimed to investigate how hip bone and muscular morphology features differ between ischiofemoral impingement (IFI) patients and healthy subjects among males and females. Three-dimensional models were reconstructed based on magnetic resonance imaging images from IFI patients and healthy subjects of different sexes. Bone morphological parameters and the cross-sectional area of the hip abductors were measured. The diameter and angle of the pelvis were compared between patients and healthy subjects. Bone parameters of the hip and cross-sectional area of the hip abductors were compared between affected and healthy hips. The comparison results of some parameters were significant for females but not males. For females, the comparison results of pelvis parameters showed that the anteroposterior diameter of the pelvic inlet (p = 0.001) and intertuberous distance (p < 0.001) were both larger in IFI patients than in healthy subjects. Additionally, the comparison results of hip parameters showed that the neck shaft angle (p < 0.001) and the cross-sectional area of the gluteus medius (p < 0.001) and gluteus minimus (p = 0.005) were smaller, while the cross-sectional area of the tensor fasciae latae (p < 0.001) was significantly larger in affected hips. Morphological changes in IFI patients demonstrated sexual dimorphism, including bone and muscular morphology. Differences in the anteroposterior diameter of the pelvic inlet, intertuberous distance, neck shaft angle, gluteus medius, and gluteus minimus may explain why females are more susceptible to IFI.

Nomogram based on the final antepartum ultrasound features before delivery for predicting failed spontaneous vaginal delivery in nulliparous women

Background

Accurate identification of nulliparous women with failed spontaneous vaginal delivery (SVD) is crucial to minimize the hazards associated with obstetrical intervention (OI). While abnormal labor progression can be identified with intrapartum ultrasonography, labor-related complications may be unavoidable due to the limited time window left to the obstetrician. Antepartum ultrasound enables sufficient obstetric planning. However, there is typically a longer gap between ultrasound assessment and delivery that often lowers the prediction accuracy compared to intrapartum ultrasonography.

Objective

In this study, antepartum ultrasound assessment was included to each fetal ultrasound examination after 36 weeks of gestation until the onset of labor. We aim to establish a nomogram to predict the likelihood of failed SVD in nulliparous women using the last antepartum ultrasound findings before labor beginning.

Methods

Of the 2,143 nulliparous women recruited, 1,373 were included in a training cohort and 770 in a validation cohort, based on their delivery date. Maternal and perinatal characteristics, as well as perinatal ultrasound parameters were collected. In the training cohort, the screened correlates of SVD failure were used to develop a nomogram for determining whether a nulliparous woman would experience SVD failure. This model was validated in both training and validation cohorts.

Results

SVD failure affected 217 nulliparous women (10.13%). In the training cohort, SVD failure was independently associated with BMI [odds ratio (OR) = 1.636], FHC (OR = 1.194), CL (OR = 1.398), and PCA (OR = 0.824) (all P < 0.05). They constituted a nomogram to estimate the individual risk of SVD failure. The model obtained clinical net benefits in both the training and validation cohorts and was validated to present strong discrimination and calibration.

Conclusion

The developed nomogram based on the last antepartum ultrasound findings may be helpful in avoiding OI and its related complications by assessing the likelihood of a failed SVD in nulliparous women.

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

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

Ultrasound vs routine care before instrumental vaginal delivery: A systematic review and meta-analysis

INTRODUCTION

The objective was to report the role of intrapartum ultrasound examination in affecting maternal and perinatal outcome in women undergoing instrumental vaginal delivery.

MATERIAL AND METHODS

MEDLINE, Embase, CINAHL, Google Scholar and ClinicalTrial.gov databases were searched. Inclusion criteria were randomized controlled trials comparing ultrasound assessment of fetal head position vs routine standard care (digital examination) before instrumental vaginal delivery (either vacuum or forceps). The primary outcome was failed instrumental delivery extraction followed by cesarean section. Secondary outcomes were postpartum hemorrhage, 3rd or 4th degree perineal lacerations, episiotomy, prolonged hospital stay, Apgar score<7 at 5 min, umbilical artery pH <7.0 and base excess greater than -12 mEq, admission to neonatal intensive care unit (NICU), shoulder dystocia, birth trauma, a composite score of adverse maternal and neonatal outcome and incorrect diagnosis of fetal head position. Risk of bias was assessed using the Revised Cochrane risk-of-bias tool for randomized trials (RoB-2). The quality of evidence and strength of recommendations were assessed using the Grading of Recommendations Assessment Development and Evaluation (GRADE) methodology. Head-to-head meta-analyses using a random-effect model were used to analyze the data and results are reported as relative risk with their 95% confidence intervals.

RESULTS

Five studies were included (1463 women). There was no difference in the maternal, pregnancy or labor characteristics between the two groups. An ultrasound assessment prior to instrumental vaginal delivery did not affect the cesarean section rate compared with standard care (p = 0.805). Likewise, the risk of composite adverse maternal outcome (p = 0.428), perineal lacerations (p = 0.800), postpartum hemorrhage (p = 0.303), shoulder dystocia (p = 0.862) and prolonged stay in hospital (p = 0.059) were not different between the two groups. Composite adverse neonatal outcome was not different between the women undergoing and those not undergoing ultrasound assessment prior to instrumental delivery (p = 0.400). Likewise, there was no increased risk with abnormal Apgar score (p = 0.882), umbilical artery pH < 7.2 (p = 0.713), base excess greater than -12 (p = 0.742), admission to NICU (p = 0.879) or birth trauma (p = 0.968). The risk of having an incorrect diagnosis of fetal head position was lower when ultrasound was performed before instrumental delivery, with a relative risk of 0.16 (95% confidence interval 0.1-0.3; I2 :77%, p < 0.001).

CONCLUSIONS

Although ultrasound examination was associated with a lower rate of incorrect diagnoses of fetal head position and station, this did not translate to any improvement of maternal or neonatal outcomes.

Operative vaginal delivery: all you should know

Over the last three decades, the decrease in operative vaginal delivery (OVD) has lead to an increase in the rate of cesarean sections, giving rise to intense debate amongst healthcare providers. As the use of vacuum and forceps requires personnel be adequately trained so as to become familiar with the correct use of instruments, the lack of skilled and experienced instructors may well lead to this technique being discarded in the near future. The aim of this study was to review the literature, compare the recommendations from international OVD guidelines and to illustrate the correct technique of obstetrical vacuum and forceps application to promote OVD among clinicians as a safe way of delivery.

Automatic measurement of head-perineum distance during intrapartum ultrasound: description of the technique and preliminary results

OBJECTIVES

To evaluate the accuracy and reliability of a new ultrasound technique for the automatic assessment of the head-perineum distance (HPD) during childbirth.

METHODS

HPD was measured on a total of 40 acquisition sessions in 30 laboring women both automatically by an innovative algorithm and manually by trained sonographers, assumed as gold standard.

RESULTS

A significant correlation was found between manual and automatic measurements (Intra-CC = 0.994). High values of the coefficient of determination (r²=0.98) and low residual errors: RMSE = 2.01 mm (4.9%) were found.

CONCLUSION

The automatic algorithm for the assessment of the HPD represents a reliable technique.