Predicting the outcome of induction of labour

Clinical predictive factors for vaginal delivery following induction of labour among pregnant women in Jordan

Background

Induction of labour (IOL) is an important and common clinical procedure in obstetrics. In the current study, we evaluate predictors of vaginal delivery in both nulliparous and multiparous women in north Jordan who were induced with vaginal prostaglandins.

Method

A prospective study was conducted on 530 pregnant women at King Abdullah University Hospital (KAUH) in north Jordan. All pregnant mothers with singleton live fetuses, who had induction of labour (IOL) between July 2017 and June 2019, were included in the study. Mode of delivery, whether vaginal or caesarean, was the primary outcome. Several maternal and fetal variables were investigated. The safety and benefit of repeated dosage of vaginal prostaglandin E2 (PGE2) tablets, neonatal outcomes and factors that affect duration of labour were also evaluated.

Pearson χ2 test was used to investigate the significance of association between categorical variables, while student’s t-test and ANOVA were applied to examine the mean differences between categorical and numerical variables. Linear regression analysis was utilized to study the relation between two continuous variables. A multivariate regression analysis was then performed. Significance level was considered at alpha less than 0.05.

Results

Nulliparous women (N = 254) had significantly higher cesarean delivery rate (58.7% vs. 17.8%, p < 0.001) and longer duration of labour (16.1 ± 0.74 h vs. 11.0 ± 0.43 h, p < 0.001) than multiparous women (N = 276). In nulliparous women, the rate of vaginal delivery was significantly higher in women with higher Bishop score; the mean Bishop score was 3.47 ± 0.12 in nulliparous women who had vaginal delivery vs. 3.06 ± 0.10 in women who had cesarean delivery (Adjusted odds ratio (AOR) = 1.2, 95% CI: 1.03–1.28, p = 0.03). In multiparous women, the rate of vaginal delivery was significantly higher in women with higher Bishop scores and lower in women with higher body mass index (BMI). The mean Bishop score was 3.97 ± 0.07 in multiparous women who had vaginal delivery vs. 3.56 ± 0.16 in women who had cesarean delivery (AOR = 1.5, 95% CI: 1.1–2.1, p = 0.01). The mean BMI was 30.24 ± 0.28 kg/m² in multiparous women who had vaginal delivery vs. 32.36 ± 0.73 kg/m² in women who had cesarean delivery (AOR = 0.89, 95% CI: 0.84–0.96, p = 0.005). 27% of nulliparous women who received more than two PGE2 tablets and 50% of multiparous women who received more than two PGE2 tablets had vaginal delivery with no significant increase in neonatal morbidity.

Conclusion

Parity and cervical status are the main predictors of successful labour induction. Further studies are required to investigate the benefit of the use of additional doses of vaginal PGE2 above the recommended dose for IOL.

Risk of caesarean delivery in labour induction: a systematic review and external validation of predictive models

BACKGROUND

Despite the existence of numerous published models predicting the risk of caesarean delivery in women undergoing induction of labour (IOL), validated models are scarce.

OBJECTIVES

To systematically review and externally assess the predictive capacity of caesarean delivery risk models in women undergoing IOL.

SEARCH STRATEGY

Studies published up to 15 January 2021 were identified through PubMed, CINAHL, Scopus and ClinicalTrials.gov, without temporal or language restrictions.

SELECTION CRITERIA

Studies describing the derivation of new models for predicting the risk of caesarean delivery in labour induction.

DATA COLLECTION AND ANALYSIS

Three authors independently screened the articles and assessed the risk of bias (ROB) according to the prediction model risk of bias assessment tool (PROBAST). External validation was performed in a prospective cohort of 468 pregnancies undergoing IOL from February 2019 to August 2020. The predictive capacity of the models was assessed by creating areas under the receiver operating characteristic curve (AUCs), calibration plots and decision curve analysis (DCA).

MAIN RESULTS

Fifteen studies met the eligibility criteria; 12 predictive models were validated. The quality of most of the included studies was not adequate. The AUC of the models varied from 0.520 to 0.773. The three models with the best discriminative capacity were those of Levine et al. (AUC 0.773, 95% CI 0.720-0.827), Hernández et al. (AUC 0.762, 95% CI 0.715-0.809) and Rossi et al. (AUC 0.752, 95% CI 0.707-0.797).

CONCLUSIONS

Predictive capacity and methodological quality were limited; therefore, we cannot currently recommend the use of any of the models for decision making in clinical practice.

TWEETABLE ABSTRACT

Predictive models that predict the risk of cesarean section in labor inductions are currently not applicable.

Induction of labour: clinical predictive factors for success and failure

Induction of labour (IOL) is a widely-used practice in obstetrics. Our aim was to evaluate predictors of vaginal delivery in postdate pregnancies induced with prostaglandins. We conducted a retrospective cross-sectional study with analytic component. A total of 145 women, admitted for IOL after the 41st week of gestation, were induced with a vaginal pessary releasing prostaglandins. Type of delivery, whether vaginal or caesarean, was the outcome. Several maternal and foetal variables were investigated. The Kaplan-Maier curves, monovariate and a multivariate logistic regression were carried out. In our population, 80.7% of women had vaginal delivery after the induction. Multiparity and a high Bishop score at the beginning of the IOL were protective factors for a vaginal delivery (respectively OR 0.16, p = .028 and OR 0.62, p = .034) while age >35 years, and the foetal birth weight >3500 g at the birth, resulted in being risk factors for caesarean section (respectively OR 4.20, p = .006 and OR 3.63, p = .013). IMPACT STATEMENT What is already known on this subject: Induction of labour (IOL) is a widely used practice in obstetrics. Scientific literature shows several predictors of successful induction, although there is no unanimity except for 'multiparity' and 'favourable Bishop score' which are associated with positive outcome of the induction. The main difficulty in finding other predictive factors is the heterogeneity of this field (different local protocols in each hospital, type of induction, populations and outcomes chosen in each study). In addition to that, populations are not always comparable due to the different gestation. For this reason, we decided to select a specific population of women, such as low risk postterm pregnancies induced with prostaglandins, in order to detect possible predictive factors for the success of the IOL for women with uncomplicated pregnancies. What the results of this study add: Our study agrees with existing literature that 'multiparity' and 'Bishop score' are linked with the success of IOL and adds that 'maternal age' and 'foetal birth weight' are significant risk factors for the population of uncomplicated post term pregnancies induced with prostaglandins. What the implications are of these findings for clinical practice and/or further research: Our results agreed with the existing literature regarding parity and Bishop score but not for maternal age and birth weight. This adds new precious data to the literature which could be used for systematic reviews and for implementing IOL guidelines and protocols, nationally and internationally. Our findings could be also used for guiding future research in this field. It will be interesting to investigate the existence of not just specific factors but also any combination of variables which could predict the success of the procedure. At the moment these information cannot be used in terms of decision making for healthcare professionals as no variable is 100% predictive but once further research will be added, we may be able to know when is best time to start the IOL, how to facilitate the success of the procedure and how to best support the woman throughout the whole experience.

Pre-induction translabial ultrasound measurements in predicting mode of delivery compared to bishop score: a cross-sectional study

Background

By increased concerns about the accuracy of the traditional methods to predict outcomes after induction of labor, developing new standards has a great clinical importance. Here, we compared the predictive value of translabial ultrasound measurements with Bishop Score to determine the suitability of induction of labor.

Methods

A homogenous population of primigravid women was recruited. Induction of labor was performed with low-dose infusion of oxytocin. Translabial ultrasound and assessment of Bishop Score were performed by two different obstetricians. Receiver–operating characteristics curves were obtained to measure area under curve and subsequently, test sensitivity of each method.

Results

One hundred women entered the investigation. Maternal body mass index was significantly higher among candidates of Cesarean section (P: 0.02). Maternal age and fetus weight, gender and occiput position were not determinants of outcomes of induction of labor. Cervical length and fetal head-pubis symphysis distance measured by translabial ultrasound had a test sensitivity of 90 and 88 %, respectively which were slightly higher than sensitivity of Bishop score (84 %).

Conclusion

This study demonstrates that translabial measurements can be a suitable alternative method to monitor labor progress with an admissible predictive value compared with Bishop Score. It is a non-invasive method which provides valuable objective measurements and can be better accepted by women when considering the painful process which is required in evaluating Bishop Score.

Prognostic models in obstetrics: available, but far from applicable

Health care provision is increasingly focused on the prediction of patients' individual risk for developing a particular health outcome in planning further tests and treatments. There has been a steady increase in the development and publication of prognostic models for various maternal and fetal outcomes in obstetrics. We undertook a systematic review to give an overview of the current status of available prognostic models in obstetrics in the context of their potential advantages and the process of developing and validating models. Important aspects to consider when assessing a prognostic model are discussed and recommendations on how to proceed on this within the obstetric domain are given. We searched MEDLINE (up to July 2012) for articles developing prognostic models in obstetrics. We identified 177 papers that reported the development of 263 prognostic models for 40 different outcomes. The most frequently predicted outcomes were preeclampsia (n = 69), preterm delivery (n = 63), mode of delivery (n = 22), gestational hypertension (n = 11), and small-for-gestational-age infants (n = 10). The performance of newer models was generally not better than that of older models predicting the same outcome. The most important measures of predictive accuracy (ie, a model's discrimination and calibration) were often (82.9%, 218/263) not both assessed. Very few developed models were validated in data other than the development data (8.7%, 23/263). Only two-thirds of the papers (62.4%, 164/263) presented the model such that validation in other populations was possible, and the clinical applicability was discussed in only 11.0% (29/263). The impact of developed models on clinical practice was unknown. We identified a large number of prognostic models in obstetrics, but there is relatively little evidence about their performance, impact, and usefulness in clinical practice so that at this point, clinical implementation cannot be recommended. New efforts should be directed toward evaluating the performance and impact of the existing models.

Prostaglandin E2 labour induction with intravaginal (Minprostin) versus intracervical (Prepidil) administration at term: randomized study of maternal and neonatal outcome and patient's perception using the osgood semantic differential scales

AIM

To compare the efficacy, safety, and patient's perception of two prostaglandin E2 application methods for induction of labour.

METHOD

Above 36th weeks of gestation, all women, who were admitted to hospital for induction of labour, were prospectively randomised to intravaginal 1 mg or intracervical 0.5 mg irrespective of cervical Bishop score. The main outcome variables were induction-to-delivery interval, number of foetal blood samples, PDA rate, rate of oxytocin augmentation, rate of vaginal delivery, and patient's perception using semantic differential questionnaire.

RESULTS

Thirty-nine patients were enrolled in this study. There was no statistical significant difference between the two groups in regard to perceptions of induction. The median induction delivery time using intravaginal versus intracervical administration was 29.9 versus 12.8 hours, respectively (P = 0.04). No statistically difference between the groups was detected in regard to parity, gestation age, cervical Bishop score, number of foetal blood samples, PDA rate, rate of oxytocin augmentation, and mode of birth.

SUMMARY

Irrespective of the cervical Bishop Score, intracervical gel had a shorter induction delivery time without impingement on the women's perception of induction.

Risk factors for failed induction in nulliparous women

OBJECTIVE

To identify risk factors for failed induction in nulliparous women.

MATERIAL AND METHODS

A retrospective cohort study of nulliparous women admitted for induction of labour (IOL). Identification of risk factors for failed IOL by comparing clinical characteristics of patients with a failed IOL defined as birth by caesarean section (LSCS) with those achieving vaginal birth.

RESULTS

During a 12 month episode, 400 nulliparous women had an IOL; of these 168 (42%) failed to deliver vaginally. Independent antenatal risk factors for failed IOL were higher maternal age (OR = 1.052 per additional year), being shorter (OR = 1.112 per cm less maternal height) and a lower cervical dilatation score (OR = 1.411 per lower cervical dilatation score). A longer active phase (OR = 1.004 per additional minute) was the only independent intrapartum risk factor for having a LSCS.

CONCLUSIONS

Maternal age, height and cervical dilatation are independent antepartum risk factors, while duration of active phase is the single independent intrapartum risk factor for a failed IOL. Increased maternal BMI was less of a risk factor than anticipated with increased risk for failed IOL, as independent risk factor, more or less restricted to the morbidly obese women.

Operative vaginal deliveries: practical aspects

Forceps, vacuum, and cesarean sections are relatively recent additions to the obstetrician's armamentarium. The art of modern obstetrics is one that mandates from obstetricians the attentive vigilance of the development of natural processes and an active intervention when such processes fall outside normally accepted standards. What constitutes the "normal process" and the "accepted standard" is subject to discussion, and international variations in obstetric practice are in part the reflection of such controversies. This article presents a practical approach to the contemporary issue of instrumental deliveries, outlining supporting evidence (when available) and the most current position of professional colleges in obstetrics and gynecology.