Measures of success: Prediction of successful labor induction

Comparison of Vaginal Dinoprostone Pessary With Transcervical Balloon Catheter Plus Vaginal Misoprostol for Pre-induction Cervical Ripening: A Randomized Trial

Aims and Objectives To compare the safety and efficacy of dinoprostone pessary with Foley plus vaginal misoprostol for cervical ripening. Materials and Methods We randomized 115 women to the pessary or Foley plus misoprostol group. Pessary was inserted for 24 hours, and in the Foley plus misoprostol group, intravaginal misoprostol 25 mcg was administered along with trans-cervical Foley insertion and repeated every six hours to a maximum dose of 100 mcg. Singleton pregnancies requiring labor induction at more than 34 weeks with a Bishop score of <6 were included. Study outcomes included induction-delivery interval (IDI), mode of delivery, change in the Bishop score, need for oxytocin augmentation, and patient discomfort as assessed by visual analog score. Results The IDI was similar between the groups (pessary vs Foley plus misoprostol; 21.27 vs 21.10 hours, p = 0.9). The mean change in the Bishop score and need for augmentation with oxytocin was significantly more in the Foley plus misoprostol group compared to pessary (2.72 vs 1.94, p = 0.001; 89.7% vs 57.9%, p = 0.0001). Pessary was better tolerated compared to Foley plus misoprostol (VAS 7.8 vs 6.68, p = 0.0001). Mode of delivery and maternal and neonatal outcomes showed no difference. Conclusion There was no significant difference between pessary and Foley plus misoprostol in the IDI and mode of delivery. Pessary was better tolerated, and augmentation with oxytocin was required less often. Foley plus misoprostol caused a faster change in the Bishop score, but oxytocin augmentation was used more often. Maternal and neonatal outcomes were similar.

Prediction of an effective cervical ripenning in the induction of labour using vaginal dinoprostone

To develop a predictive model for successful cervical ripening in women that undergo induction of labour by means of a vaginal prostaglandin slow-release delivery system (Propess®).  Prospective observational study on 204 women that required induction of labour between February 2019 and May 2020 at "La Mancha Centro" hospital in Alcázar de San Juan, Spain. The main variable studied was effective cervical ripening (Bishop score > 6). Using multivariate analysis and binary logistic regression, we created three initial predictive models (model A: Bishop Score + Ultrasound cervical length + clinical variables (estimated fetal weight, premature rupture of membranes and body mass index)); model B: Ultrasound cervical lenght + clinical variables; and model C: Bishop score + clinical variables) to predict effective cervical ripening. All three predictive models obtained (A, B and C) presented good predictive capabilities, with an area under the ROC curve ≥ 0.76. Predictive model C, composed of the variables: gestational age (OR 1.55, 95% CI 1.18-2.03, p = 0.002), premature rupture of membranes (OR 3.21 95% CI 1.34-7.70, p = 0.09) body mass index (OR 0.93, 95% CI 0.87-0.98, p = 0.012), estimated fetal weight (OR 0.99, 95% CI 0.99-1.00, p = 0.068) and Bishop score (OR 1.49 95% CI 1.18-1.81, p = 0.001), is presented as the model of choice with an area under the ROC curve of 0.76 (95% CI 0.70-0.83, p < 0.001). A predictive model composed of the variables: gestational age, premature rupture of membranes, body mass index, estimated fetal weight and Bishop score upon admission presents good capabilities in predicting successful cervical ripening following administration of prostaglandins. This tool could be useful in making clinical decisions with regard to induction of labour.

Evidence-Based Approaches to Labor Induction

Importance

The induction rate continues to increase in the United States placing pressure on the health care system with increasing cost and time spent on labor and delivery. Most labor induction regimens have evaluated uncomplicated singleton-term gestations. Unfortunately, the optimal labor regimens of medically complicated pregnancies have not been well described.

Objective

The aim of this study was to review the current available evidence regarding the various labor induction regimens and understand the evidence that exists for induction regimens in complicated pregnancies.

Evidence Acquisition

Data were acquired by a literature search on PubMed, ClinicalTrials.gov, the Cochrane Review database, the most recent American College of Obstetricians and Gynecologists practice bulletin on labor induction, and a review of the most recent edition on widely used obstetric texts for key words related to labor induction.

Results

Many heterogeneous clinical trials exist examining various labor induction regimens such as prostaglandin only, oxytocin only, or a combination of mechanical dilation with prostaglandins or oxytocin. Several Cochrane systematic reviews have been performed, which suggest a combination of prostaglandins and mechanical dilation results in an improved time to delivery when compared with single-use methods. Evaluating pregnancies complicated by maternal or fetal conditions, there exist retrospective cohorts describing significantly different labor outcomes. Although a few of these populations have planned or active clinical trials, most do not have an optimal labor induction regimen described.

Conclusions and Relevance

Most induction trials are significantly heterogeneous and limited to uncomplicated pregnancies. A combination of prostaglandins and mechanical dilation may result in improved outcomes. Complicated pregnancies have significantly different labor outcomes; however, almost none have well-described labor induction regimens.

Systematic Review of Evening Primrose (Oenothera biennis) Preparations for the Facilitation of Parturition

BACKGROUND

The objective of this systematic review was to characterize the efficacy and safety of evening primrose (EP) for facilitation of parturition in peripartum persons.

METHODS

This search sought records related to the efficacy and safety of EP preparations to facilitate parturition. Eligibility criteria were primary literature with efficacy or safety outcomes reported; studied in peripartum persons; and available in English. Records were excluded if they were available as abstracts only. Data was synthesized by study characteristics, patient demographics, and outcomes. The RoB2 and ROBINS-I were used to assess risk of bias.

RESULTS

A total of 11 studies met inclusion criteria: seven randomized placebo-controlled trials, one randomized non placebo-controlled trial, one case study, one observational retrospective study, and one quasi-experimental cross-sectional study. Efficacy outcomes included Bishop scores and duration of labor during the different phases. Reported adverse events were generally mild and included increased blood pressure, decreased heart rate, pain, bleeding, nausea, and vomiting. Important risks of bias exist across the literature reviewed.

CONCLUSIONS

The use of EP for parturition in peripartum individuals is not recommended. Further research is warranted before use during parturition or the peripartum period. Other: The authors deny conflicts of interest. The study was neither registered nor funded.

Factors Predicting Successful Vaginal Delivery Following Induction of Labor in Term Pregnancy

PURPOSE

This study was proposed to evaluate factors predicting a successful vaginal delivery following labor induction and develop induction prediction model in term pregnancy among Thai pregnant women.

PATIENTS AND METHODS

We conducted a retrospective cohort study using electronic medical records of 23,833 deliveries from April 2010 to July 2021 at tertiary care university hospital in Bangkok, Thailand. Univariate regression was performed to identify the association of individual parameters to successful vaginal delivery. Multiple logistic regression analysis of all possible variables from univariate analysis was performed to develop a prediction model with statistically significant of p value <0.05.

RESULTS

Of the total 809 labor-induced pregnancies, the vaginal delivery rate was 56.6%. Among predicting variables, history of previous vaginal delivery (aOR 5.75, 95% CI 3.701-8.961), maternal delivery BMI <25 kg/m² (aOR 2.010, 95% CI 1.303-3.286), estimated fetal weight <3500 g (aOR 2.193, 95% CI 1.246-3.860), and gestational age ≤39 weeks (aOR 1.501, 95% CI 1.038-2.173) significantly increased the probability of a successful vaginal delivery following labor induction. The final prediction model has been internally validated. Model calibration and discrimination were satisfactory with Hosmer-Lemeshow test P = 0.21 and with AUC of 0.756 (95% CI 0.695-0.816).

CONCLUSION

This study determined the pragmatic predictors for successful vaginal delivery following labor induction comprised history of previous vaginal delivery, maternal delivery BMI <25 kg/m², estimated fetal weight <3500 g, and gestational age ≤39 weeks. The final induction prediction model was well-performing internally validated prediction model to estimate individual probability when undergoing induction of labor. Despite restricted population, the predicting factors and model could be useful for further prospective study and clinical practice to improve induction outcomes.

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.

Relations between second-trimester aneuploidy screening results and prediction of labour induction success in term pregnancies

We aimed to assess whether the second-trimester maternal serum markers could be used for the prediction of labour induction success. This prospective study enrolled women planned labour induction at term. Women were assigned to one of two groups: vaginal prostaglandin or balloon dilatation. All patients were evaluated for Bishop score, maternal serum oestriol, human chorionic gonadotropin and progesterone at the time of second-aneuploidy screening. The total successful rate for induction of labour was 63.9% in both groups. Maternal serum oestriol multiple of median (MoM) values were significantly lower among the caesarean section group compared to the vaginal delivery group (p < .001). A MoM value of 0.74 for oestriol was associated with a sensitivity of 75.9%, specificity of 41.0%, a positive predictive value of 76.6% and a negative predictive value of 58.0% for a successful induction of labour. Oestriol had a good performance in the prediction of successful induction of labour at term.IMPACT STATEMENTWhat is already known on this subject? Induction of labour is a common procedure undertaken whenever the benefits of prompt delivery outweigh the risks of expectant management. Previous studies have reported that a decreased progesterone/oestradiol ratio and increased maternal plasma oestriol levels are associated with successful labour. What the results of this study add? The results of this study showed that second-trimester oestriol multiple of median (MoM) value provide a significant contribution to the efforts of the prediction of successful induction of labour in term pregnancy, having a sensitivity of 69.8%, specificity of 92.4%, positive predictive value of 83.3% and negative predictive value of 82.5%.What the implications are of these findings for clinical practice and/or further research? This finding can be used as an additional method for prediction of labour induction as well as multiparity and Bishop score. This adds new valuable data to the literature which could be used for systematic reviews and for implementing guidelines and protocols on labour induction.

Elective Induction at 39 Weeks of Gestation and the Implications of a Large, Multicenter, Randomized Controlled Trial

On August 8, 2018, Grobman et al published the findings from the ARRIVE (A Randomized Trial of Induction Versus Expectant Management) trial, a large randomized controlled trial of elective induction of labor in nulliparous women at 39 weeks of gestation compared with expectant management. Conducted by the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network, the trial found there was no difference between the two groups in the primary outcome, a composite of neonatal morbidity. Also, there was a reduction in rates of cesarean delivery and hypertensive disorders of pregnancy in the elective induction group. The topic of elective induction has been of interest to clinicians for decades, and research has yielded inconsistent results in the past. This trial offers the best evidence thus far to address this complex issue. Our objective is to briefly review the history and literature regarding elective induction of labor, discuss the recently published ARRIVE trial, and consider its implications on clinical practice and health policy.

Target populations to reduce cesarean rates after induced labor: A national population-based cohort study

INTRODUCTION

Great variations in cesarean rates after induction of labor exist and reasons for these disparities remain unclear. They may be explained by individual characteristics or obstetric practices. Ten-group classification systems have proved their utility to monitor cesarean rates in general population. We aimed to identify groups of women that account for most cesareans after induction of labor using the Nippita reproducible 10-group classification, specifically designed for induced population.

MATERIAL AND METHODS

A prospective population-based cohort study was performed in 94 French maternity units, including 3042 women undergoing induction of labor. Women were sorted according to 10 mutually exclusive groups based on parity, weeks of gestation, number of fetuses, fetal presentation and previous cesarean delivery. Relative size, cesarean delivery rate and contribution to the overall cesarean rate were described for each group. Cesarean rates were compared according to the Bishop score at the onset of labor induction. Indications for cesarean delivery were also described in the groups that contributed most to the overall cesarean rate. The MEDIP protocol was registered in ClinicalTrial (NCT02477085).

RESULTS

The overall cesarean rate was 21.0% among this population of induced women. Nulliparous women with a term singleton cephalic fetus (groups 1, 2 and 3; at 37-38, 39-40 and ≥41 weeks of gestation, respectively) accounted for two-thirds of the overall cesarean rate because they were the largest group (relative size of 10.6, 16.6 and 18.1%, respectively) and had higher cesarean rates (27.2, 30.9 and 33.0%, respectively). When the Bishop score was <6 (n = 2270/3042), cesarean delivery rates were higher (24.1 vs 10.7% if Bishop score ≥6, P < 0.01), in particular for group 1 (29.1 vs 12.5%, P = 0.02), and group 2 (33.3 vs 19.3%, P = 0.01). In groups 1, 2 and 3, which contributed most to the overall cesarean rate, a significant part of the cesareans were performed before 6 cm of cervical dilation for dystocia only (40.0, 16.7 and 17.6%, respectively).

CONCLUSIONS

Nulliparous women with a term singleton cephalic fetus and an unfavorable cervix represent the population to target for auditing induction practices. Specific actions could be implemented among this population to weigh the benefits and risks of induction and improve the management of labor induction.

Recent advances in the induction of labor

The rate of labor induction is steadily increasing and, in industrialized countries, approximately one out of four pregnant women has their labor induced. Induction of labor should be considered when the benefits of prompt vaginal delivery outweigh the maternal and/or fetal risks of waiting for the spontaneous onset of labor. However, this procedure is not free of risks, which include an increase in operative vaginal or caesarean delivery and excessive uterine activity with risk of fetal heart rate abnormalities. A search for “Induction of Labor” retrieves more than 18,000 citations from 1844 to the present day. The aim of this review is to summarize the controversies concerning the indications, the methods, and the tools for evaluating the success of the procedure, with an emphasis on the scientific evidence behind each.

Cervical consistency index and risk of Cesarean delivery after induction of labor at term

OBJECTIVE

To evaluate the association between the cervical consistency index (CCI) and the risk of Cesarean delivery after planned induction of labor (IOL) at term.

METHODS

This was a prospective observational study of women with a term singleton pregnancy admitted for IOL due to maternal or fetal indication. Ultrasonographic images were obtained before IOL and CCI was calculated offline once recruitment was completed. The main outcome was defined as Cesarean delivery due to failed IOL or arrest of labor. Cesarean deliveries indicated due to maternal or fetal compromise (Van Dillen's grade 1 or 2) were excluded from analysis. Univariate statistical analysis was performed using Fisher's exact test and Student's t-test for categorical and continuous variables, respectively. Multivariate analysis was performed using logistic regression, including CCI and other variables related to the main outcome. Intraclass correlation coefficients were used to estimate intra- and interobserver agreement.

RESULTS

Of 510 women admitted for IOL during the study period and for whom image quality was adequate, 46 were excluded due to emergency Cesarean delivery leaving 464 pregnancies for analysis. Cesarean section due to failed IOL or arrest of labor was performed in 100/464 (21.6%) pregnancies. The mean CCI of women who underwent Cesarean delivery was not significantly different from that in those who had vaginal delivery after IOL (70.1 ± 12.3% vs 70.0 ± 13.1%; P = 0.94). Multivariate analysis also showed absence of statistical association between CCI and Cesarean delivery for failed IOL or arrest of labor. Intraclass correlation coefficients for intra- and interobserver agreement were 0.81 (95% CI, 0.66-0.89) and 0.86 (95% CI, 0.75-0.92), respectively.

CONCLUSION

CCI does not seem to be associated with the risk of Cesarean delivery after IOL. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Maternal age and body mass index at term: Risk factors for requiring an induced labour for a late-term pregnancy

INTRODUCTION

We investigated the role of body mass index (BMI) and maternal age on the risk of late-term induction, prolonged induction time and caesarean section (CS) after induction.

MATERIAL AND METHODS

This is a retrospective, observational study. All women without any fetal or maternal pathological condition, uterine scars or any other indication for an elective caesarean birth and had a singleton foetus in the cephalic position at term were included.

RESULTS

A total of 4006 women had a spontaneous onset of labour and 612 were induced for a late-term pregnancy. Labour induction was significantly more common in overweight (Adj Odds Ratio (OR) 1.48 95%CI 1.22-1.78) and obese (Adj OR 1.63 95%CI 1.24-2.14) women. Among induced women, a BMI ≥ 30 was a risk factor for a prolonged induction time in both nulliparous (AdjOR 2.4, 95%CI 1.02-5.67) and multiparous women (AdjOR 4.24, 95%CI 1.02-17.6). A BMI > 25-29.9 was significantly associated with a prolonged induction time only in nulliparous women (AdjOR 1.86 95%CI 1.05-3.30). A CS was more frequent in overweight (AdjOR 1.74, 95% CI 1.052.89) and obese women (AdjOR 2.72, 95%CI 1.42-5.25). Nulliparous women ageed 30-34 years had an induction time longer than women <30 years (OR 2.04 95%CI 1.07-3.91).

CONCLUSIONS

The results of this study suggest that a BMI > 25 kg/m2 at term of pregnancy is a risk factor for the induction of labour during a late-term pregnancy, a prolonged induction time and higher caesarean section rate.

Induction of labor in twin gestation: can we predict success?

Objective:

To identify factors associated with a successful induction of labor in twin pregnancies and associated maternal morbidity.

Study design:

This was a retrospective review of twin pregnancies ≥24 weeks’ gestation undergoing labor induction from 2011 to 2016. The primary outcome was a successful induction of labor. The secondary outcome was a composite of maternal morbidity, including ≥1 of the following: estimated blood loss (EBL) >1500 ml, blood transfusion, hysterectomy, intensive care unit (ICU) admission or maternal death.

Results:

Of 104 twin pregnancies undergoing labor induction, 64 (61.5%) had a vaginal delivery of both twins. Multiparity [odds ratio (OR) 12.3, 95% confidence interval (CI) 3.9–38.8, P≤0.005] and maternal age <35 years (OR 2.33, 95% CI 1.1–5.2, P=0.038) were independently associated with vaginal delivery. The overall rate of composite maternal morbidity was 7.7%. Cesarean delivery (CD) was associated with an increased rate of composite maternal morbidity compared to the successful induction group (17.5% vs. 1.6%, P≤0.005). An EBL >1500 ml, uterine atony and the use of ≥1 uterotonic agent were more frequent in the CD group.

Conclusions:

Multiparous women and those <35 years of age were more likely to have a vaginal delivery. Maternal morbidity is increased in women who required a CD after labor induction compared to those who achieved a vaginal delivery.

Comparison of outcomes between induction of labor and spontaneous labor for term breech - A systemic review and meta analysis

OBJECTIVES

Few studies have assessed the impact of induction of labor on breech presentation. This study aims to summarize the effect of induction of labor of breech presentation on perinatal morbidity.

METHODS

Literature review was done in Medline, Embase, Web of science and Cochrane Library up to 20 October 2017. Randomized control studies, cohort studies, and case control publishing studies comparing induction of labor versus spontaneous labor of singleton live breech birth were included. Perinatal morbidity was calculated by RevMan 5 and presented by pooled odds ratio with 95% confidence intervals.

RESULTS

Cesarean section rate and neonatal intensive care unit admission were increased in induction of breech labor as compared with spontaneous breech labor. No significant difference in umbilical cord blood base excess ≤ -12 mmol/L, Apgar 5 min < 7, Apgar 5 min < 4, umbilical cord blood PH < 7, neonatology unit admission, maternal fever, and intrapartum stillbirth between the two groups was found.

CONCLUSIONS

Induction of breech labor has higher cesarean section rate and NICU perinatal morbidity compared to spontaneous breech labor. The neonatal outcomes were otherwise similar across both groups. Eligibility for induction of breech labor needs to be assessed carefully according to individual situation.

Placental and maternal serum activin A in spontaneous and induced labor in late-term pregnancy

PURPOSE

Feto-placental unit represents an important source of activin A, a member of transforming growth factors-β involved in the mechanisms of labor. No evidences are available on activin A in pregnancies beyond 41 weeks of gestation, where induction of labor is often required. The present study aimed to evaluate activin A maternal serum levels and placental mRNA expression in term and late-term pregnancy, with spontaneous or induced labor, and its possible role to predict the response to labor induction.

METHODS

Maternal serum samples and placental specimens were collected from women with singleton pregnancy admitted for either term spontaneous labor (n = 23) or induction of labor for late-term pregnancy (n = 41), to evaluate activin A serum levels and placental mRNA expression. Univariate and multivariate analyses on activin A serum levels, maternal clinical parameters, and cervical length were conducted in women undergoing induction of labor.

RESULTS

Maternal serum activin A levels and placental activin A mRNA expression in late-term pregnancies were significantly higher than at term. Late-term pregnancies who did not respond to induction of labor showed significantly lower levels of activin A compared to responders. The combination of serum activin A and cervical length achieved a sensitivity of 100% and a specificity of 93.55% for the prediction of successful induction.

CONCLUSION

Late-term pregnancy is characterized by hyperexpression of placental activin A and increased maternal activin A secretion. By combining maternal serum activin A levels with cervical length, a good predictive model for the response to induction of labor was elaborated.