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.

Sonographic cervical length predicts vaginal delivery after previous cesarean section in women with low Bishop score induced with a double-balloon catheter

OBJECTIVE

To assess the role of cervical length when predicting vaginal delivery after a previous cesarean section (CS) in women with low Bishop score following the use of a double-balloon catheter for induction of labor (IOL).

METHODS

A prospective, longitudinal study was conducted at a large teaching hospital in Santiago to recruit pregnant women at term with a previous CS and Bishop score ≤6 for IOL with a double-balloon catheter. The device was maintained for up to 24 h and the patient continued IOL with oxytocin only if the Bishop score was >6. Demographic and clinical variables were recorded and compared against vaginal delivery as the primary outcome. Multivariate logistic regression analysis was used to compare perinatal demographic and clinical variables in women achieving vaginal delivery versus those having a repeat CS.

RESULTS

The final cohort included 40 pregnant women. Women achieving vaginal delivery (n = 17, 42.5%) had statistically significant differences in mean cervical length (24.8 mm versus 33.4 mm, respectively; p = .006), median Bishop score after removing the double-balloon catheter (11 versus 7, respectively; p = .005), and mean interval between double-balloon catheter placement and vaginal delivery or the decision to perform a CS (17.4 h versus 23.6 h, respectively; p = .03). Backward stepwise selection revealed an odds ratio of 0.90 (95% confidence interval = 0.82-0.98) for cervical length and a receiver operating characteristic curve area of 0.73.

CONCLUSION

Cervical length, as determined by transvaginal sonography, proved to be effective in predicting vaginal delivery in women with a previous CS and low Bishop score following the use of a double-balloon catheter for IOL.

Antenatal cervical length measurement as a predictor of successful vaginal birth

Background

Antenatal cervical length measurement has paramount importance in the prediction of labor. It was compared to the Bishop Score and incorporated in the modified Bishop score due to its relevance and convenience. It is a more accurate tool that imposes no harm or distress to the patients. The study aimed to evaluate the role of antenatal cervical length measurement in the prediction of a successful vaginal birth and its relation to the duration of labor.

Methods

This was a prospective cohort study, conducted at the emergency ward of obstetrics and gynecology department. We recruited 162 women over 1 year from January 2018 to January 2019. Women eligible for the study had a transvaginal ultrasound for the examination of the cervical length before the onset of labor. The success of vaginal delivery was evaluated.

Results

The mean cervical length (mm) was 43.3 ± 8.0. The majority of the patients labored spontaneously [102 (63.0%)] while the remaining ones required induction of labor due to different causes. One hundred and eight patients (66.7%) had a successful vaginal delivery. The cervical length was significantly shorter among patients who delivered vaginally than those delivered by CS (P-value < 0.001). Multiple factors had a significant role in the prediction of the mode of delivery (cervical length, BMI, the onset of labor, parity). Maternal body mass index and labor induction were associated with a prolonged duration of the active phase of labor.

Conclusion

Antenatal cervical length measurement predicted the mode of delivery as well as the gestational age at which delivery ensued. It can be used in patients’ counseling regarding the mode of delivery.

Can the Progression Angle before Labor Help to Predict Cesarean Section?

OBJECTIVE

The aim of this study was to predict cesarean section on a single visit at term using a combination of maternal history and ultrasound markers, including some new markers such as the progression angle used to assess intrapartum progress.

STUDY DESIGN

This was an observational prospective cohort study of singleton term pregnancies that included 575 women. The maternal history and ultrasound markers were obtained on a single visit at 37-38 weeks' gestation. Multivariable logistic regression was used for prediction of cesarean section.

RESULTS

Five hundred and seventy-five women were examined at a median gestational age of 38.3 weeks (range: 35.6-41.6) and a cesarean section was performed on 104 women (18%) - 24 for a fetal indication and 80 for a maternal indication. The risk of cesarean section increased with a previous cesarean section, assisted reproduction techniques, a higher estimated fetal weight, and a greater cervical length, and decreased with a greater maternal height, multiparity, and a wider progression angle. The detection rate for a 20% false positive rate was 69.9% for all cesarean sections, 54.2% for those with a fetal indication, and 77.2% for those with a maternal indication.

CONCLUSIONS

Assessment at 37-38 weeks' gestation of ultrasound markers such as the cervical length, progression angle, and estimated fetal weight, in combination with the maternal history, can predict a cesarean section in labor. Cesarean section for a maternal indication is better predicted than cesarean section for a fetal indication.