Intrapartum translabial ultrasound with pushing used to predict the difficulty in vacuum-assisted delivery of fetuses in non-occiput posterior position

Can assessing the angle of progression before labor onset assist to predict vaginal birth after cesarean?: A prospective cohort observational study

OBJECTIVE

To assess whether pre-labor measurement of the angle of progression (AOP) can assist in predicting a successful vaginal birth after cesarean in women without a previous vaginal birth.

METHODS

A prospective observational cohort study performed in a single tertiary center including women at term with a single previous cesarean delivery (CD), without prior vaginal births, who desire a trial of labor. Transperineal ultrasound was used to measure the AOP before the onset of labor. The managing staff in the delivery suite was blinded to the ultrasound measurements. Clinical data and delivery outcome were retrieved from medical records. The study was approved by the institutional ethics committee (KMC 0117-10).

RESULTS

Of the 111 women included in the study, 67 (60.4%) had a successful vaginal birth after CD. Women were sonographically assessed at a median of 3 days [interquartile range (IQR) 1-3 days] prior to delivery. The median AOP was significantly narrower in women who eventually underwent a CD than in those who delivered vaginally (88°, IQR 78-96° vs. 99°, IQR 89-107°, respectively; p < .001). An AOP >98° (derived from a receiver operating characteristic curve) was associated with a successful vaginal birth after CD in 87.5% of women. Multivariable regression analysis demonstrated that each additional 1° in the AOP increases the chance for a successful vaginal birth after CD by 6%.

CONCLUSIONS

Pre-labor AOP may be a useful sonographic tool for predicting vaginal birth after CD and can assist in consulting primiparous women with a prior CD opting for a trial of labor.

Ultrasound before operative vaginal delivery: why and how

Safe management of the second stage of labor is important. Wait for spontaneous delivery, operative vaginal deliveries and second stage cesarean sections are all options when prolonged second stage occurs. The important question is which option to choose. Fetal head station and fetal head position are used to decide mode of delivery; this has traditionally been decided by performing a digital vaginal examination. Studies have shown that theses clinical examinations of both fetal head station and position are unreliable and that ultrasound might be better option. The International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) published in 2018 guidelines on intrapartum ultrasound and recommends that ultrasound is performed for ascertainment of fetal head position and station before considering or performing an instrumental vaginal delivery for slow progress or arrested labor in the second stage. The determination of the fetal head position, fetal head station and the movement of the fetal head can easily be determined with the help of ultrasound and can help the clinicians in making the right decision on how to proceed when prolonged second stage of labor is diagnosed.

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.

Predicting the Mode of Delivery by Angle of Progression (AOP) before the Onset of Labor by Transperineal Ultrasound in Nulliparous Women

Background:

Prediction of the mode of delivery is crucial for better labour outcome. Recent studies suggest that the angle of progression (AOP), measured using transperineal ultrasound, can substantially aid the assessment of fetal head descent during labor, thereby predicting the mode of delivery.

Objective:

To assess the ability of the AOP measured by transperineal ultrasound to predict the mode of delivery in nulliparous women before the onset of labor.

Methods:

A prospective observational study was conducted at our hospital, of nulliparous women who had presented to the antenatal clinic at ≥ 38 weeks of gestation but not in labor. AOP was measured using transperineal ultrasonography and compared among the women having Caesarean section (CS) due to labor dystocia and vaginal delivery (VD). Various other confounding factors which increase the risk of caesarean section were analyzed.

Results:

Among total 120 nulliparous women, the mean AOP was narrower in patients undergoing CS (n = 28) compared to those with VD (n = 92) (91.6 ± 6.1° vs. 100.7 ± 6.9°; P < 0.01). Multivariable logistic regression analysis revealed that narrow AOP values (OR 3.66; P < 0.001; 95% CI 1.7- 14.5) and occiput-posterior fetal position (OR 1.63; P = 0.04; 95% CI 1.0-7.5) were the independent risk factors for CS. An AOP ≥ 96° (calculated from the ROC curve) was associated with VD in 95% (76/80) of women and an AOP < 96° was observed among 60% (24/40) of women who underwent CS.

Conclusion:

Narrow AOP (< 96°) and occiput-posterior fetal position are at higher risk for CS due to labor dystocia. AOP measured at the antenatal period could accurately predict the mode of delivery, thereby modifying labor outcome.