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

Abstract

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; P¼.003), cervical length (odds ratio, 1.08; P¼.04), angle of progression at rest (odds ratio, 0.9; P¼.001), and occiput posterior position (odds ratio, 5.7; P¼.006). 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, 0.71e0.87) and 0.88 (95% confidence inte...

A Peripheral Immune Signature of Labor Induction

“…Much of the literature surrounding failed induction of labor use different or poorly defined endpoints such as failure to delivery vaginally, not achieving vaginal delivery within 24 hrs, or not entering the active phase of labor. However, our work now justifies to design studies in larger cohorts with the aim of identifying predictive immune markers of failed induction of labor prior to commencement of active labor (9,(45)(46)(47)(48). Potential future clinical studies should also include parallel analyses of choriodecidual material to help understand local immune responses.…”

“…Unfortunately, the time interval between labor induction, the establishment of latent labor (defined as regular contractions leading to cervical changes from 0 to 6 cm) and the onset of active labor (defined as cervical dilatation ≥ 6 cm with regular uterine contractions ≤ 3 min apart) remains unpredictable. Similarly, induction complications associated with failure of successful labor initiation, prolonged labor progression, subsequent labor arrest, development of chorioamnionitis or failed induction resulting in cesarean delivery (7)(8)(9), are difficult to predict. Prolonged labor is associated with severe complications and morbidity for the mother and her offspring, most importantly chorioamnionitis, uterine atony and postpartum hemorrhage (4).…”

The usefulness of ultrasound before induction of labor

“…Some studies reported that the fetal occiput and spine position determination by ultrasound, preinduction, do not correlate with the mode of birth while others concluded that fetal head position is, indeed, a significant predictor. 52,[59][60][61] Identifying the fetal spine and occiput position by ultrasound is done transabdominally. The curvilinear transducer is applied to the maternal abdomen to get an axial view of the fetal abdomen to visualize the fetal spine location then the transducer is slid down the maternal abdomen systematically to reach the fetal head.…”

“…The determination of fetal head station by measuring the angle of progression (AoP) was found to be a significant independent predictor for the success of induction of labor and particularly when associated with nulliparity. 61,65,66 Angle of progression (Figure 5) is the angle between the sagittal midline of the symphysis pubis and line dropping from the lowermost point of the symphysis pubis tangentially to the deepest point of the fetal head, on transperineal ultrasound. 67 The automated assessment of AoP, now available in some ultrasound systems, measures the AoP in a parasagittal plane and was demonstrated to be feasible, correlate well with assessment of fetal station by vaginal examination 68 and in excellent agreement with the originally described midsagittal AoP 69 .…”

“…Many of these predictive models have been validated with varying reported results. 55,61,70,[97][98][99][100][101] The quest for the ultimate model that enables the proper selection of patients eligible for IOL will continue, with the ultimate need for its prospective validation. The aims are to enable proper counseling and informed choice for women and also to reduce the rate of failures of IOL with the consequent reduction in all associated negative impacts.…”