Defining failed induction of labor

Failed induction of labor

Induction of labor is a widely used practice. From 2016 to 2019, >1 in 3 women giving birth in the United States did so after undergoing labor induction. The obvious goal of labor induction is vaginal birth with minimal maternal or neonatal morbidity. To achieve this goal, criteria for failed labor induction are needed. Herein, we provide an evidence-based approach to safely prevent unnecessary cesarean deliveries for failed induction. Although there are no randomized trials comparing failed labor induction criteria, the observational data have been consistent: if the status of the mother and the fetus permits, at least 12 to 18 hours of oxytocin should be administered after membrane rupture before deeming an induction of labor to have failed because of nonprogression to the active phase of labor.

Parturition at term: induction, second and third stages of labor, and optimal management of life-threatening complications-hemorrhage, infection, and uterine rupture

Childbirth is a defining moment in anyone's life, and it occurs 140 million times per year. Largely a physiologic process, parturition does come with risks; one mother dies every two minutes. These deaths occur mostly among healthy women, and many are considered preventable. For each death, 20 to 30 mothers experience complications that compromise their short- and long-term health. The risk of birth extends to the newborn, and, in 2020, 2.4 million neonates died, 25% in the first day of life. Hence, intrapartum care is an important priority for society. The American Journal of Obstetrics & Gynecology has devoted two special Supplements in 2023 and 2024 to the clinical aspects of labor at term. This article describes the content of the Supplements and highlights new developments in the induction of labor (a comparison of methods, definition of failed induction, new pharmacologic agents), management of the second stage, the value of intrapartum sonography, new concepts on soft tissue dystocia, optimal care during the third stage, and common complications that account for maternal death, such as infection, hemorrhage, and uterine rupture. All articles are available to subscribers and non-subscribers and have supporting video content to enhance dissemination and improve intrapartum care. Our hope is that no mother suffers because of lack of information.

The use of adjunctive mechanical dilation at the time of induction termination and adverse health outcomes: a systematic review

OBJECTIVE

This study aimed to assess if the use of mechanical dilation at the time of induction termination is associated with changes in the time from initiation of labor to expulsion of the fetus (induction-to-expulsion interval) and with the frequency of health complications when compared with medication management alone.

DATA SOURCES

PubMed, CINAHAL, Scopus, and the Cochrane Central Register of Controlled Trials were queried from January 2000 to May 2023.

STUDY ELIGIBILITY CRITERIA

We included randomized controlled trials of individuals who were assigned to undergo mechanical dilation (ie, laminaria, Dilapan-S, and intracervical Foley balloon catheter) in combination with the use of medication and compared it with the outcomes of medication use (eg, prostaglandins, antiprogestins, oxytocin) alone.

METHODS

The primary outcome was the induction-to-expulsion interval. The secondary outcomes were the incidence of clinical chorioamnionitis, sepsis, hemorrhage, the need for blood transfusion and uterotonics, cervical laceration, the need for adjunctive procedures (eg, dilation and curettage), failed induction termination, uterine rupture, intensive care unit admission, or death. Assessment of bias was performed using the Cochrane Risk of Bias tool. A subgroup analysis was performed among studies deemed to be at low risk of bias.

RESULTS

Of 864 abstracts identified, 11 met the inclusion criteria. Five studies demonstrated a shorter induction-to-expulsion interval among those randomized to mechanical dilation, whereas 6 studies demonstrated a similar or longer induction-to-expulsion interval. There were no significant differences reported in the frequency of any adverse outcomes between the trial arms. In addition, most studies (8/11) exhibited moderate to high levels of bias. In an analysis of the 3 studies deemed to have a low risk of bias, 1 (n=60) demonstrated a longer induction-to-expulsion interval with adjunctive laminaria, 1 (n=60) demonstrated a shorter induction-to-expulsion interval with adjunctive intracervical Foley balloon catheter use, and 1 demonstrated no difference in the induction-to-expulsion interval with adjunctive Dilapan-S use (n=180).

CONCLUSION

Only a small number of studies, most of which were of low quality, assessed mechanical dilation for induction termination. The results of these studies were inconsistent in terms of the induction-to-expulsion interval of adjunctive mechanical methods in comparison with medication management alone. Studies did not reveal significant differences between the groups in adverse outcomes. Further research should investigate the use of mechanical dilation at the time of induction termination using high-quality methods.

First and Second Stage Labor Management: ACOG Clinical Practice Guideline No. 8

PURPOSE

The purpose of this document is to define labor and labor arrest and provide recommendations for the management of dystocia in the first and second stage of labor and labor arrest.

TARGET POPULATION

Pregnant individuals in the first or second stage of labor.

METHODS

This guideline was developed using an a priori protocol in conjunction with a writing team consisting of one maternal-fetal medicine subspecialist appointed by the ACOG Committee on Clinical Practice Guidelines-Obstetrics and two external subject matter experts. ACOG medical librarians completed a comprehensive literature search for primary literature within Cochrane Library, Cochrane Collaboration Registry of Controlled Trials, EMBASE, PubMed, and MEDLINE. Studies that moved forward to the full-text screening stage were assessed by the writing team based on standardized inclusion and exclusion criteria. Included studies underwent quality assessment, and a modified GRADE (Grading of Recommendations Assessment, Development, and Evaluation) evidence-to-decision framework was applied to interpret and translate the evidence into recommendation statements.

RECOMMENDATIONS

This Clinical Practice Guideline includes definitions of labor and labor arrest, along with recommendations for the management of dystocia in the first and second stages of labor and labor arrest. Recommendations are classified by strength and evidence quality. Ungraded Good Practice Points are included to provide guidance when a formal recommendation could not be made because of inadequate or nonexistent evidence.

Prediction model for labour dystocia occurring in the active phase

To establish and verify a model for labour dystocia occurring in the active phase, this study retrospectively analysed the clinical data of primiparas with singleton cephalic full-term foetuses, who had delivered after a trial of labour. The Chi-square test, t-test, Mann-Whitney U test and multivariate logistic regression analysis were used for statistical analysis. Based on the model a nomogram was established using the R programming language. Multivariate logistic regression analysis showed that the foetal abdominal circumference, premature rupture of membranes (PROM), prolonged latent phase, foetal station and foetal position at the early stage of the active phase were independent factors influencing labour dystocia occurring in the active phase. The established model could effectively and accurately support clinicians in the early identification of labour dystocia to improve maternal and infant outcomes.Impact statementWhat is already known on this subject? Labour dystocia occurring during the active phase of the first stage, is the most commonly diagnosed as labour aberration. Previous studies have suggested that maternal age, body mass index, macrosomia and abnormal foetal position are the independent risk factors for labour dystocia. However, only the risk factors were reported, and few prediction models were established.What do the results of this study add? This study uses data in the real world to establish a prediction model of full-term singleton primipara with labour dystocia occurring in the active phase by logistic regression analysis. Foetal abdomen circumference, PROM, prolonged latent phase, the foetal station and foetal position at the early stage of the active phase are independent factors influencing labour dystocia that occurs in the active phase. In addition, a nomogram is established as a visual graph to predict the probability of it.What are the implications of these findings for clinical practice and/or further research? The nomogram based on the predictive model discarded complicated calculations and presented an easy visual graph-based method to predict the probability of labour dystocia occurring in the active phase. It helps to introduce interventions that could reduce the CS rate and occurrence of adverse maternal and foetal outcomes to ensure the safety of mothers and infants.

Maternal and Perinatal Outcomes Amongst Nulliparous Singleton Pregnancies Electively Induced at 39 Weeks: A Prospective Observational Study

Introduction

Given the uncertainty of inducing beyond 39 weeks, we intended to study the maternal and neonatal mortality and morbidity associated with planned elective induction of labour (eIOL) at 390/7 to 396/7 weeks.

Objectives

To study the maternal and perinatal outcomes, after eIOL, at 390/7 to 396/7 weeks, amongst nulliparous singleton pregnancies, followed up for the duration of their hospital stay.

Methods

All consecutive nulliparous, singleton gestations, undergoing eIOL, at 390/7 to 396/7 weeks, with no plan for caesarean section (CS) or contraindication for vaginal delivery were prospectively recruited. The primary outcome studied was the incidence of CS and neonatal intensive care requirement, and the secondary outcomes studied were induction-delivery interval, incidence of chorioamnionitis, postpartum haemorrhage, meconium aspiration syndrome (MAS), APGAR ≤ 7 at 1 min and neonatal mortality.

Results

Amongst the total 304 mothers electively induced at 390/7 to 396/7 weeks, 80 (26.3%) mothers underwent CS and 48 (15.8%) neonates required intensive care. Fifteen (4.9%) babies required respiratory support at birth. The mean induction-delivery interval was 19 h 42 min ± 10 h. There were 9(3%) cases of PPH and no reported cases of chorioamnionitis. Eleven (3.6%) babies had an APGAR < / = 7 at 1 min and 9 (2.9%) had MAS, but there was no maternal or neonatal mortality.

Conclusion

Induction of labour at 39 weeks in low-risk nulliparous women did not result in a lower frequency of CS or adverse perinatal outcomes.

Association of maternal Body Mass Index and parity on induced labor stages

BACKGROUND

Obesity is a widespread pandemic and obstetric care must adapt to meet the needs of obese pregnant women. Little is known about the impact of Body Mass Index (BMI) on the induction of labor (IOL). Therefore, our objective was to evaluate if the duration of the first and second stages of IOL is affected by maternal BMI in nulliparous and multiparous women.

METHODS

We included singleton pregnancies at term with cephalic presentation whose labor was induced from June 2018 to December 2019. Women were divided into two groups according to pre-pregnancy BMI in normal weight and obese women.

RESULTS

A total of 668 women with IOL were included in the study, among them, 349 had a normal weight and 321 were obese. The first stage of labor was longer in obese multiparous than normal-weight women (normal weight 81.98±71.7 vs. obese 134.3±158.1 min, P=0.000), while the second stage resulted significantly shorter (normal weight 22.2±27.8 vs. obese 14.3±14.2 min, P=0.000). The total time elapsed from IOL beginning and delivery was significantly higher in obese nulliparous (normal weight 10.4±19.7 vs. obese 22.0±26.2 h, P=0.000). Operative vaginal deliveries, emergency cesarean section, and failed IOL resulted to be similar between the groups.

CONCLUSIONS

Obese multiparous women have longer first stages of labor while shorter second stages. The total time for induced obese nulliparous to reach delivery is higher than the normal weight. It might be reasonable to reconsider the partographs according to maternal BMI in case of induced labor for future obstetric practice.

A Retrospective Comparative Study of the Effect of Controlled-Release Dinoprostone Vaginal Delivery System (Propess®) and Mechanical Methods for Cervical Ripening in Nulliparous Women in Late-Term Pregnancy

OBJECTIVE

The effects of the controlled-release dinoprostone vaginal delivery system (Propess®) and mechanical methods for cervical ripening in nulliparous women in late-term pregnancy were compared retrospectively.

METHODS

This retrospective comparative study included 46 nulliparous pregnant women (24 in the Propess® group and 22 in the mechanical methods groups) with a low Bishop score (≤1) who needed labor induction at 41 weeks of gestation. The primary outcome was the success rate of cervical ripening (= Bishop score >6 or vaginal delivery) by the next day following the insertion of Propess® only or mechanical cervical dilation only. In the cases in which cervical ripening was unsuccessful, other methods were performed, and the success rate of cervical ripening the day after was compared as the secondary outcome.

RESULTS

As the primary outcome, there was not a significant difference in the success rate of cervical ripening between the Propess® and mechanical methods groups (21 vs. 22%, p = 0.88). As for the secondary outcomes, there was not a significant difference in the total success rate of cervical ripening between the two groups (75 (5+13/24) vs. 73 (5+11/22)%, p = 0.86)). Of the unsuccessful cervical ripening cases as secondary outcomes, the Bishop score of all was ≤2 on the second day of hospitalization.

CONCLUSION

The combined use of Propess® and mechanical methods was effective for cervical ripening in nulliparous women with a low Bishop score in late-term pregnancy, regardless of order.

Validated Calculators Predicting Cesarean Delivery After Induction: Accuracy in an External Population

OBJECTIVE

To evaluate the performance of two previously published calculators in predicting cesarean delivery after induction of labor in an external population.

METHODS

This was a cohort study including all nulliparous pregnant patients with singleton, term, vertex fetuses; intact membranes; and unfavorable cervices who underwent induction of labor between 2015 and 2017 at an academic tertiary care institution. Individual predicted cesarean risk scores were calculated with two previously published calculators. For each calculator, patients were stratified into three risk groups (lower, middle, and upper thirds) of approximately equivalent size. Predicted and observed incidences of cesarean delivery were compared with two-tailed binomial tests of probability in the overall population and in each risk group.

RESULTS

A total of 846 patients met inclusion criteria, and 262 (31.0%) had cesarean deliveries, which was significantly lower than overall predicted rates of 40.0% and 36.2% with the two calculators (both P<.01). Both calculators significantly overestimated risk of cesarean delivery in higher risk tertiles (all P<.05). The areas under the receiver operating characteristic for both calculators were 0.57 or less in the overall population and in each risk group, suggesting poor predictive value. Higher predicted risk tertile in both calculators was not associated with any maternal or neonatal outcomes except wound infection.

CONCLUSION

Both previously published calculators had poor performance in this population, with neither calculator accurately predicting the incidence of cesarean delivery. Patients and health care professionals might be discouraged regarding trial of labor induction by falsely high predicted risk-of-cesarean scores. We caution against widespread implementation of these calculators without further population-specific refinement and adjustment.

Failed induction of labor in term nulliparous women with an unfavorable cervix: Comparison of cervical ripening by two forms of vaginal prostaglandins (slow-release pessary and vaginal gel)

OBJECTIVE

To compare the rate of failed induction after cervical ripening by two forms of vaginal prostaglandins.

MATERIAL AND METHODS

This two-year retrospective study (January 1, 2016, through December 31, 2017) in two tertiary maternity units included nulliparous women with a singleton fetus in cephalic presentation and an unfavorable cervix requiring labor induction for prolonged pregnancy. The principal endpoint was the rate of failed induction, defined by the performance of a cesarean delivery before 6 cm of dilation. Cervical ripening was initiated by prostaglandins for 24 h, using a slow-release pessary (unit A) or a vaginal gel (unit B). The care protocol of the two groups after the first 24 h were similar. The women's individual characteristics were compared between the two units. The rates of failed induction were then compared between the two units, first by univariate and then by multivariable analysis adjusted for the characteristics that differed significantly between the units.

RESULTS

Among the 17,217 women delivered in the two maternity units during the study period, 178 met our inclusion criteria (125 in unit A (slow-release pessary) and 53 in unit B (vaginal gel)). The rate of failed induction was similar: 21.6% in unit A (slow-release pessary) and 17.0% in unit B (vaginal gel) (P = 0.48). The multivariate analysis did not show any difference about failed induction, time from the onset of induction to delivery, and vaginal delivery rate within 24h.

CONCLUSION

The rate of failed induction of labor did not differ between slow-release pessary and vaginal gel.

Predictive factors for vaginal delivery by induction of labor in uncomplicated pregnancies at 40-41 gestational weeks: A Japanese prospective single-center cohort study

AIM

We investigated cervical parameters predictive of vaginal delivery in elective labor induction among women at 40-41 gestational weeks.

METHODS

This Japanese prospective single-center cohort study was conducted between July 2019 and June 2020. We enrolled women with an uncomplicated singleton pregnancy who underwent labor induction at 40-41 gestational weeks. We analyzed background characteristics and cervical parameters, including Bishop score, cervical length, posterior cervical angle, and changes in cervical parameters before and after cervical dilatation. The endpoint was the rate of vaginal delivery.

RESULTS

Of 142 eligible participants, all 24 multiparous women underwent vaginal delivery. Among the nulliparous women (n = 118), the following categories showed significantly higher rates of vaginal delivery: Bishop scores of ≥6 before and after dilatation, compared with Bishop score <6 (adjusted prevalence ratio (aPR) [95% confidence interval (CI)]; 1.58 [1.17-2.13] and 1.56 [1.13-2.14], respectively) and cervical length of <10 and 10-20 mm before dilation, compared with cervical length of >30 mm (aPR [95% CI]; 1.47 [1.00-2.15] and 2.13 [1.42-3.18], respectively). The posterior cervical angle and other background characteristics showed no significant associations. Furthermore, women with cervical lengths of ≥20 mm before and <20 mm after dilatation showed a higher rate of vaginal delivery, compared to cervical length of ≥20 mm even after dilatation (aPR [95% CI]; 1.95 [1.19-3.20]).

CONCLUSIONS

High Bishop score, short cervical length, and changes in cervical length with dilatation are potential independent predictors of vaginal delivery following elective labor induction in nulliparous women at 40-41 gestational weeks.

Childbirth experience in induced labor: A prospective study using a validated childbirth experience questionnaire (CEQ) with a focus on the first birth

Objective

First birth and labor induction are risk factors for negative childbirth experiences. As labor inductions are increasing, research into this high-risk group’s childbirth experiences is important. We aimed to investigate whether nulliparity or factors related to labor induction, labor, and delivery explain the association.

Methods

This was a prospective study of 711 women undergoing labor induction at Helsinki University Hospital, Finland, between January 1, 2019, and January 31, 2020. The participants answered the Childbirth Experience Questionnaire (CEQ) after delivery (response rate 69.4%). The patient characteristics and delivery outcomes were collected from patient records. We analyzed the results for nulliparous and parous women.

Results

The mean CEQ scores were 2.9 (SD 0.5) for nulliparous women (n = 408) and 3.2 (SD 0.5) for parous women (n = 303), on a scale of 1–4; higher scores represent more positive experiences. However, 7.3% of the women had negative childbirth experiences (8.8% nulliparous; 5.3% parous, p = 0.08). Negative experiences were associated with a cesarean section (OR 6.7, 95% CI 1.8–9.3, p < 0.001) and a hemorrhage ≥ 1500 ml in vaginal delivery (OR 2.8, 95% CI 1.1–7.5, p = 0.03). In the separate CEQ domains analyses, nulliparity was associated with negative experiences in the “Own Capacity” domain (OR 1.6, 95% CI 1.0–2.4, p = 0.03). Cervical ripening, oxytocin use, and daytime delivery were associated with negative experiences in at least one domain, whereas epidural or spinal analgesia was regarded positively in two domains and negatively in one.

Conclusions

Nulliparous women undergoing labor induction risk negative childbirth experiences mainly due to labor and delivery-related factors, similar to parous women. Their perceptions of their capacity and preparedness for labor and delivery should be enhanced antenatally. An effective labor induction protocol promoting as high a rate of vaginal delivery as possible and preparedness to promptly respond to postpartum hemorrhage are key for avoiding negative childbirth experiences.

Achieving an appropriate cesarean birth (CB) rate and analyzing the changes using the Robson Ten-Group Classification System (TGCS): Lessons from a Tertiary Care Hospital in Italy

BACKGROUND

To describe the interventions that were implemented at a Tertiary University Hospital and how they affected the rate of cesarean birth (CB) and main obstetrics and neonatal outcomes.

STUDY DESIGN

An analysis of the contemporaneously collected data from all deliveries that occurred from 2014 to 2018. Major obstetric and neonatal outcomes were analyzed and grouped according to the Ten-Group Classification System (TGCS).

RESULTS

A significant decrease in CB rates, from 28.4% to 23.0% (P < 0.001), was found over the study period. Although the relative sizes of both nulliparous (groups 1 + 2) and multiparous (groups 3 + 4) women remained stable over the study period, a significantly higher incidence of CB was reported in 2014 for both groups, compared with 2018 (2.6% vs. 13.0%, P < 0.001 for nulliparous women and 7.5% vs. 3.3%, P < 0.001 for multiparous women). In contrast, the relative size of Group 5 was significantly lower in 2014 than in 2018 (9.9% vs. 11.5%, P = 0.003), but a 13.3% reduction in CB was also reported for this group. No significant differences were noted in the occurrence of major obstetrics and neonatal outcomes that were reported.

CONCLUSIONS

A reduction in CB rate may be safely achieved through implementing a multifaceted strategy.

Comparison of primiparous women's childbirth experience in labor induction with cervical ripening by balloon catheter or oral misoprostol - a prospective study using a validated childbirth experience questionnaire (CEQ) and visual analogue scale (VAS)

INTRODUCTION

Primiparity and labor induction, especially when cervical ripening is required, are risk factors for a negative childbirth experience. Our aim was to compare childbirth experience in primiparous women with cervical ripening by balloon catheter or oral misoprostol using the validated Childbirth Experience Questionnaire (CEQ). We also wanted to compare assessment of a negative childbirth experience by visual analogue scale (VAS) and CEQ.

MATERIAL AND METHODS

This is a prospective study of 362 primiparous women undergoing cervical ripening and labor induction by balloon catheter (67.4%) or oral misoprostol (32.6%) at Helsinki University Hospital, Finland, between January 1, 2019 and January 31, 2020. After delivery, the women assessed their childbirth experience using the CEQ, and patient records provided the patient characteristics, delivery outcomes and VAS ratings. We analyzed the results using IBM SPSS Statistics.

RESULTS

Overall, the women experienced their labor and delivery rather positively, with a mean CEQ score of 2.9 (SD 0.6) (scale 1-4), and no differences were detectable when comparing women with cervical ripening by balloon catheter or misoprostol. However, women with balloon catheter were more often satisfied with the method chosen for them and would choose the same method in a future pregnancy. Compared with CEQ, VAS seems mainly to reflect the women's perception of their own capacity to give birth and the safety of the hospital setting, not the level of professional support or participation in decision-making. According to our results, CEQ and VAS are comparable, but the usability of the CEQ is limited by its inability to distinguish the most negative and the most positive experiences, and the VAS is limited by its simplicity.

CONCLUSIONS

Women with cervical ripening by balloon catheter or oral misoprostol experienced their childbirth rather positively, results being similar in both groups. However, women with cervical ripening by balloon catheter were more content with their labor induction. The CEQ and VAS can both be used to assess the childbirth experience of primiparous women undergoing labor induction, but both methods have limitations.

Comparison of delivery outcomes in low-dose and high-dose oxytocin regimens for induction of labor following cervical ripening with a balloon catheter: A retrospective observational cohort study

A variety of oxytocin regimens are used for labor induction and augmentation. Considering the increasing rates of labor induction, it is important to assess the most optimal oxytocin regimen without compromising maternal and fetal safety. The aim of this study was to compare delivery outcomes of low-dose and high-dose oxytocin induction protocols. This retrospective cohort study of 487 women comparing low-dose oxytocin protocol (n = 280) and high-dose oxytocin protocol (n = 207) in labor induction following cervical ripening by balloon catheter was performed in Helsinki University Hospital after implementation of a new oxytocin induction protocol. The study included two six-month cohorts from 2016 and 2019. Women with vital singleton pregnancies ≥37 gestational weeks, cephalic presentation, and intact amniotic membranes were included. The primary outcome was the rate of vaginal delivery. The secondary outcomes were the rates of maternal and neonatal infections, postpartum hemorrhage, umbilical artery blood pH-value, admission to neonatal intensive care, and induction-to-delivery interval. Statistical analyses were performed by using IBM SPSS Statistics for Windows (Armonk, NY, USA). The rate of vaginal delivery was higher [69.9% (n = 144) vs. 47.9% (n = 134); p<0.004] and the rates of maternal and neonatal infection were lower during the new high-dose oxytocin protocol [maternal infections 13.6% (n = 28) vs. 22.1% (n = 62); p = 0.02 and neonatal infection 2.9% (n = 6) vs. 14.6% (n = 41); p<0.001, respectively]. The rates of post-partum hemorrhage, umbilical artery blood pH-value <7.05 or neonatal intensive care admissions did not differ between the cohorts. The median induction-to-delivery interval was shorter in the new protocol [32.0 h (IQR 18.5–42.7) vs. 37.9 h (IQR 27.8–52.8); p<0.001]. In conclusion, implementation of the new continuous high-dose oxytocin protocol resulted in higher rate of vaginal delivery and lower rate of maternal and neonatal infections. Our experience supports the use of high-dose continuous oxytocin induction regimen with a practice of stopping oxytocin once active labor is achieved, and a 15–18-hour maximum duration for oxytocin induction in the latent phase of labor following cervical ripening with a balloon catheter.

Failed induction of labor and associated factors in Adama Hospital Medical College, Oromia Regional State, Ethiopia

Background:

Failed induction of labor continues to be a public health challenge throughout the world. This failed induction of labor is associated with a higher rate of maternal and fetal morbidity because it increases the unwanted effect of emergency cesarean section. It is also associated with an increased risk of numerous adverse maternal and perinatal outcomes such as uterine rupture, nonreassuring fetal heart rate tracing, postpartum hemorrhage, stillbirth, and severe birth asphyxia. Thus, this study was aimed to assess the failed induction of labor and associated factors in the Adama Hospital Medical College, Oromia Regional State, Ethiopia.

Methods:

A facility-based cross-sectional study was conducted from 1 to 30 December 2020 in Adama Hospital Medical College, Ethiopia. A total of 379 women who underwent labor induction in the Adama Hospital Medical College from December 2019 to November 2020 were enrolled in the study. The participants’ charts were selected using a simple random sampling technique. Data were collected using a pretested and validated structured questionnaire. Descriptive statistics were carried out using frequency tables, proportions, and summary measures. Predictors were assessed using a multivariable logistic regression analysis model and reported using adjusted odds ratio with 95% confidence interval. Statistical significance was considered at a p value <0.05.

Results:

Of 379 induced labor included in the study, the proportion of failed induction was found to be 29.6% (95% confidence interval (25.2, 34.3)). Prelabor rupture of the membrane was found to be the most common indication for induction of labor (46.4%) followed by a hypertensive disorder of pregnancy (21.6%). In the final model of multivariable analysis, predictors such as: nulliparity (adjusted odds ratio = 2.32, 95% confidence interval (1.08, 5.02)), unfavorable cervical status (adjusted odds ratio = 3.46, 95% confidence interval (1.51, 7.94)), prelabor rupture of membrane (adjusted odds ratio = 2.60, 95% confidence interval (1.14, 5.91)), hypertensive disorder of pregnancy (adjusted odds ratio = 3.01;95% confidence interval (1.61, 558)), preinduction membrane status (adjusted odds ratio = 3.63; 95% confidence interval (1.48, 8.86)), and birth weight of greater than 4000 g (adjusted odds ratio = 4.33; 95% confidence interval (1.44, 13.02)) were statistically associated with failed induction of labor.

Conclusion:

The prevalence of failed induction of labor was relatively high in this study area because more than a quarter of mothers who underwent induction of labor had failed induction. This calls for all stakeholders to adhere to locally available induction protocols and guidelines. In addition, pre-induction conditions must be a top priority to improve the outcome of induction of labor.

Association between route of delivery and maternal adverse outcomes in pregnancies complicated by preterm birth

INTRODUCTION

To determine the impact of route of delivery on maternal outcomes among individuals who deliver preterm (before 37 weeks).

MATERIALS AND METHODS

This was a population-based retrospective cohort study using the U.S. vital statistics datasets on Period Linked Birth-Infant Death Data from 2014 to 2018. The study population was restricted to live births from women with non-anomalous singletons who delivered at 24-36 weeks of gestation. The main explanatory variable for this study was route of delivery, which was categorized as: (i) vaginal delivery, (ii) cesarean delivery with labor, and (iii) cesarean delivery without labor. The primary outcome was composite maternal adverse outcome, which encompassed any of the following: admission to the intensive care unit, maternal blood transfusion, uterine rupture, or unplanned hysterectomy. The results were presented as adjusted relative risk (aRR) with 95% confidence interval (CI).

RESULTS

Over the study period 1,440,510 live births met the inclusion criteria, and the overall composite maternal adverse outcome was 14.38 per 1,000 live births. After multivariable adjustment, compared to women who underwent a vaginal delivery, the risk of composite maternal adverse outcome was higher in women who had a cesarean delivery with labor (aRR 3.70; 95% CI 3.52-3.90) and those who had a cesarean delivery without labor (aRR 4.79; 95% CI 4.59-4.98).

CONCLUSION

With preterm birth, cesarean delivery without labor has higher rate of composite maternal morbidity than cesarean during labor or vaginal delivery.

American College of Nurse-Midwives Clinical Bulletin Number 18: Induction of Labor

Induction of labor is an increasingly common component of intrapartum care in the United States. This rise is fueled by a nationwide escalation in both medically indicated and elective inductions at or beyond term, supported by recent research showing some benefits of induction over expectant management. However, induction of labor medicalizes the birth experience and may lead to a complex cascade of interventions. The purpose of this Clinical Bulletin is twofold: (1) to guide clinicians on the use of person-centered decision-making when discussing induction of labor and (2) to review evidence-based practice recommendations for intrapartum midwifery care during labor induction.

Prevalence and factors associated with failed induction of labor in Worabe Comprehensive Specialized Hospital, Southern Ethiopia

Background

Induction of labor is one of the most used obstetric procedures in the world. It is performed in around 20% of all pregnancies. Failed induction of labor, on the other hand, has been associated with poorer mother and newborn health outcomes. Besides, there is a scarcity of data on the current burden and drivers. Therefore, this study aimed to assess the prevalence and factors associated with failed induction in Worabe Comprehensive Specialized Hospital, Southern Ethiopia.

Methods

A retrospective cross-sectional study was conducted on medical records of mothers who delivered through induction of labor during September 1^st, 2018 to August 30^th, 2020. The samples were collected using a systematic sampling technique. The data was extracted using a checklist. Data were entered into EpiData (version 3.1) and analyzed using SPSS (version 24). Multivariable logistic regression analyses were used to decide the association of explanatory variables with the outcome variable. Odds ratio with their 95% CI were calculated to identify the presence and strength of an association. A p-value of < 0.05 was used to declare statistical significance.

Results

In this study, the prevalence of failed induction was observed to be 22.2%. The associated factors included rural residence (AOR = 5.7, 95% CI: 3.12–11.02), primiparity (AOR = 8.4, 95% CI: 2.72–22.36) and unfavourable bishop score (AOR = 5.9, 95% CI: 4.52–16.12).

Conclusions

In comparison to the rate reported in developed countries, the study area had a high rate of failed induction. Being rural residence, primiparity and unfavourable bishop score were the associated factors of failed induction. Therefore, to reduce of the rate of failed induction, health care practitioners should analyze cervical status (using Bishop Score) to decide the possibility of successful induction, with a focus on associated factors like parity.

Neighborhood deprivation increases the risk of Post-induction cesarean delivery

OBJECTIVE

The purpose of this study was to measure the association between neighborhood deprivation and cesarean delivery following labor induction among people delivering at term (≥37 weeks of gestation).

MATERIALS AND METHODS

We conducted a retrospective cohort study of people ≥37 weeks of gestation, with a live, singleton gestation, who underwent labor induction from 2010 to 2017 at Penn Medicine. We excluded people with a prior cesarean delivery and those with missing geocoding information. Our primary exposure was a nationally validated Area Deprivation Index with scores ranging from 1 to 100 (least to most deprived). We used a generalized linear mixed model to calculate the odds of postinduction cesarean delivery among people in 4 equally-spaced levels of neighborhood deprivation. We also conducted a sensitivity analysis with residential mobility.

RESULTS

Our cohort contained 8672 people receiving an induction at Penn Medicine. After adjustment for confounders, we found that people living in the most deprived neighborhoods were at a 29% increased risk of post-induction cesarean delivery (adjusted odds ratio = 1.29, 95% confidence interval, 1.05-1.57) compared to the least deprived. In a sensitivity analysis, including residential mobility seemed to magnify the effect sizes of the association between neighborhood deprivation and postinduction cesarean delivery, but this information was only available for a subset of people.

CONCLUSIONS

People living in neighborhoods with higher deprivation had higher odds of postinduction cesarean delivery compared to people living in less deprived neighborhoods. This work represents an important first step in understanding the impact of disadvantaged neighborhoods on adverse delivery outcomes.

Outcome of induction and associated factors among induced labours in public Hospitals of Harari Regional State, Eastern Ethiopia: A two years' retrospective analysis

Background

Induction of labor (IOL) is an essential intervention to reduce adverse maternal and neonatal outcomes. It is also improved pregnancy outcomes, especially in resource-limited countries, where maternal and perinatal mortality is unacceptably high. However, there is a scarcity of evidence regarding the outcome of induction of labor and its predictors in low-income countries like Sub-Saharan Africa. Therefore, this study was aimed at assessing the outcome of induction of labor and associated factors among mothers who underwent labor induction in public Hospitals of Harari Regional State, Estern Ethiopia.

Methods

A facility-based cross-sectional study was conducted from 1 to 30 March, 2019 in Harari Regional State, Eastern Ethiopia. A total of 717 mothers who underwent induction of labor in public Hospitals of Harari Regional State, Eastern Ethiopia from January 2017 to December 2018 were enrolled in the study. Data were collected using a pretested structured questionnaire. The collected data were entered into Epi-data version 3.1 and exported to SPSS version 24 (IBM SPSS Statistics, 2016) for further analysis. A multivariable logistic regression analysis was performed to estimate the effects of each predictor variable on the outcome of induction of labor after controlling for potential confounders. Statistical significance was declared at p-value <0.05.

Results

Overall, the prevalence of success of induction of labor was 65% [95% CI (61.5, 68.5)]. Pre-eclampsia/eclampsia was found to be the most common indication for induction of labor (46.70%) followed by pre-labor rupture of fetal membrane (33.5%). In the final model of multivariable analysis, predictors such as: maternal age < 24 years old [AOR = 1.93, 95%CI(1.14, 3.26)], nulliparity[AOR = 0.34, 95%CI(0.19, 0.59)], unfavorable Bishop score [AOR = 0.06, 95%CI(0.03, 0.12)], intermediate Bishop score [AOR = 0.08, 95%CI(0.04, 0.14)], misoprostol only method [AOR = 2.29, 95%CI(1.01, 5.19)], nonreassuring fetal heart beat pattern [AOR = 0.14, 95%CI (0.07, 0.25)] and Birth weight 3500 grams and above[AOR = 0.32, 95% CI (0.17, 0.59)] were statistically associated with the successful outcome of induction of labor.

Conclusion

The prevalence of successful of induction of labor was relatively low in this study area because only two-thirds of the mothers who underwent induction of labor had a successful of induction. Therefore, this result calls for all stakeholders to give more emphasis on locally available induction protocols and guidelines. In addition, pre-induction conditions must be taken into consideration to avoid unwanted effect of failed induction of labour.

A Peripheral Immune Signature of Labor Induction

Approximately 1 in 4 pregnant women in the United States undergo labor induction. The onset and establishment of labor, particularly induced labor, is a complex and dynamic process influenced by multiple endocrine, inflammatory, and mechanical factors as well as obstetric and pharmacological interventions. The duration from labor induction to the onset of active labor remains unpredictable. Moreover, prolonged labor is associated with severe complications for the mother and her offspring, most importantly chorioamnionitis, uterine atony, and postpartum hemorrhage. While maternal immune system adaptations that are critical for the maintenance of a healthy pregnancy have been previously characterized, the role of the immune system during the establishment of labor is poorly understood. Understanding maternal immune adaptations during labor initiation can have important ramifications for predicting successful labor induction and labor complications in both induced and spontaneous types of labor. The aim of this study was to characterize labor-associated maternal immune system dynamics from labor induction to the start of active labor. Serial blood samples from fifteen participants were collected immediately prior to labor induction (baseline) and during the latent phase until the start of active labor. Using high-dimensional mass cytometry, a total of 1,059 single-cell immune features were extracted from each sample. A multivariate machine-learning method was employed to characterize the dynamic changes of the maternal immune system after labor induction until the establishment of active labor. A cross-validated linear sparse regression model (least absolute shrinkage and selection operator, LASSO) predicted the minutes since induction of labor with high accuracy (R = 0.86, p = 6.7e-15, RMSE = 277 min). Immune features most informative for the model included STAT5 signaling in central memory CD8⁺ T cells and pro-inflammatory STAT3 signaling responses across multiple adaptive and innate immune cell subsets. Our study reports a peripheral immune signature of labor induction, and provides important insights into biological mechanisms that may ultimately predict labor induction success as well as complications, thereby facilitating clinical decision-making to improve maternal and fetal well-being.

Review of Evidence-Based Methods for Successful Labor Induction

Induction of labor is increasingly a common component of the intrapartum care. Knowledge of the current evidence on methods of labor induction is an essential component of shared decision-making to determine which induction method meets an individual's health needs and personal preferences. This article provides a review of the current research evidence on labor induction methods, including cervical ripening techniques, and contraction stimulation techniques. Current evidence about expected duration of labor following induction, use of the Bishop score to guide induction, and guidance on the use of combination methods for labor induction are reviewed.

Quantifying the Risks and Benefits of Continuing Labor Induction: Data for Shared Decision-Making

OBJECTIVE

This study aimed to quantify the relative maternal and fetal risks and benefits of continuing labor induction.

STUDY DESIGN

This retrospective cohort study included nulliparous women with nonanomalous, singleton, vertex, term pregnancies undergoing labor induction with intact membranes at a tertiary-care academic hospital from January 2015 to April 2017. The primary outcome was mode of delivery. Secondary outcomes included hemorrhage, transfusion, infection, and composite neonatal morbidity. The data were analyzed using chi-square and Fisher's exact tests. Multivariable regression was used to control for potential confounders.

RESULTS

A total of 955 patients met the inclusion criteria. The median induction duration was 32.3 hours (interquartile range: 20.4-41 hours) and the vaginal delivery rate was 70.5% (n = 673). The chance of vaginal delivery at 12, 24, 36, 48, 60, and ≥60 hours was 76, 83, 77, 74, 72, and 48%, respectively. After controlling for confounders, there was a 20% decrease in chance of vaginal delivery with induction ≥ 24 hours compared with induction < 24 hours. The adjusted relative risks of hemorrhage, transfusion, and infection with induction ≥ 24 hours compared with induction < 24 hours were 1.9, 2.2, and 2.7, respectively (95% confidence interval [CI] of 1.4-2.5, 1.1-3.9, and 1.8-4.0, respectively). The relative risk for these outcomes remained stable or decreased at each subsequent time point. The increasing risks of hemorrhage and infection were primarily among patients who underwent cesarean delivery. There was no association between induction duration and neonatal morbidity.

CONCLUSION

In this cohort, the chance of vaginal delivery remained nearly 50% even when induction extended beyond 60 hours. Risks of hemorrhage and maternal infection rose modestly over time, but primarily in patients who underwent cesarean delivery. There was no difference in the risk of transfusion beyond 24 hours and no association between induction duration and neonatal morbidity. These findings may be useful when engaging patients in shared decision-making during labor induction.

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

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; P=.003), cervical length (odds ratio, 1.08; P=.04), angle of progression at rest (odds ratio, 0.9; P=.001), and occiput posterior position (odds ratio, 5.7; P=.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, 0.71-0.87) and 0.88 (95% confidence interval, 0.79-0.97) for the developed and validated models, respectively.

CONCLUSION

Maternal age and sonographic fetal occiput position, angle of progression at rest, and cervical length before labor induction are very good predictors of induction outcome in nulliparous women at term.

Physiology and Pathology of Contractility of the Myometrium

Uterine atony is a serious obstetrical complication since it is the leading cause of postpartum hemorrhage. Postpartum hemorrhage (PPH) is one of the 5 major causes of postpartum mortality; therefore, it requires immediate medical intervention, independent of whether delivery occurs normally or with a cesarean section. While in the past years most cases of postpartum hemorrhage were caused due to uterine atony following vaginal delivery, in recent years most PPH cases indicate a significant association with cesarean delivery. There are several methods used in order to avoid such a life-threatening complication, ranging from risk assessment to prevention, and finally medical intervention and management, if such an event occurs. In this scientific paper emphasis is given on the so-called "uterotonic" agents that are currently used, including oxytocin among others. It is, therefore, important to be familiar with these agents as well as understand the physiological mechanism by which they work, since they are used in everyday practice, not only for managing but also for preventing PPH. There are several potential questions that arise from the use of such "uterotonic" agents, and most specifically of oxytocin. Maybe one of the most important issues is the determination of optimal dosing of oxytocin in order to avoid PPH after a cesarean section.

Hospital-Level Variation in the Frequency of Cesarean Delivery Among Nulliparous Women Who Undergo Labor Induction

OBJECTIVE

To evaluate the use of administrative data for identification of labor induction and to estimate the variation in cesarean delivery rates among low-risk women who underwent labor induction.

METHODS

A cross-sectional study was performed examining live births in California hospitals during 2016 and 2017 using birth certificate data linked with maternal patient discharge records. Initially, eight hospitals performed medical record reviews by using reVITALize definitions on 46,916 deliveries to assess the validity of induction identification by birth certificate or discharge diagnosis records or both. Hospital-level variation in cesarean delivery rates was then assessed among all California hospitals for women with low-obstetric-risk first births before and after further risk adjustment and after the exclusion of potential medical and obstetric indications for induction. Variation in physician-level cesarean delivery rates after induction at four large hospitals also was examined. The relationships between cesarean delivery rates among women with induced labors compared with noninduced labors and with the hospital rate of induction also were explored.

RESULTS

Identifying induction by a combination of discharge diagnosis codes and birth certificate data had the highest accuracy (92.9%, 95% CI 92.7-93.2). Among 917,225 births at 238 birthing hospitals, there were 99,441 nulliparous women with term, singleton, vertex pregnancies who were induced. The median cesarean delivery rate after labor induction for nulliparous women with term, singleton, vertex pregnancies was 32.2%, with a range of 18.5-84.6%. This wide variation was not reduced after risk adjustment or after exclusion of all women with induction indications. A similar wide variation was noted within geographic regions, neonatal intensive care levels, and among individual physicians in the same facility. Only very weak associations were found for the cesarean delivery rate after labor induction and either the rate after noninduced labor (R<0.08) or the rate of nulliparous labor induction (R<0.12).

CONCLUSION

The large variation of cesarean delivery rates after induction of labor suggests that clinical management plays an important role in achieving induction success.

Cervical Ripening and Labor Induction and Augmentation, 5th Edition

Cervical ripening and induction and augmentation of labor are common procedures in labor and birth units. The potential risks and benefits for the procedure should be explained to women so that they can make informed decisions. Clinicians should be knowledgeable about the methods and medications used and be skilled in maternal-fetal assessment. Adequate nurse staffing is required to monitor the mother and fetus to promote the best possible outcomes. This practice monograph includes information on mechanical and pharmacologic methods for cervical ripening; labor induction and augmentation with oxytocin, a high alert drug; and nurse staffing levels and skills needed to provide safe and effective care during cervical ripening and labor induction and augmentation.

Changes in the obstetrical emergency department profile during the COVID-19 pandemic

BACKGROUND

The COVID-19 outbreak caused persons to be reluctant to seek medical care due to fear of contracting the infection.

OBJECTIVES

To evaluate the effect of the COVID-19 pandemic on admission rates to the delivery room and the feto-maternal unit, and to assess the effect on the nature of presenting obstetrical complaints to the emergency department.

STUDY DESIGN

A retrospective cohort study in one medical center. The population was women > 20 weeks pregnant who presented to the obstetrical emergency department with self-complaints during 29 days at the peak of the pandemic outbreak, and a matched group during the exact period in the previous year. We compared between the groups: clinical, obstetrical, and demographic data, including age, area of residence, gravidity, parity, previous cesarean deliveries, high-risk pregnancy follow-up, the last 30 days admissions to the obstetrical emergency department, gestational age, chief complaints, cervical dilatation, cervical effacement, admissions to the delivery room or feto-maternal unit, time from admissions to the delivery room to birth, if applicable, and acute obstetrical complications diagnosed at the emergency department.

RESULTS

During the pandemic outbreak, 398 women met study inclusion criteria, compared to 544 women in the matched period of the previous year. During the COVID-19 period, women visited the obstetrical emergency department at a more advanced mean gestational age (37.6 ± 3.7 vs. 36.7 ± 4.6, p = .001). Higher proportions of women in the COVID-19 cohort presented in active labor, defined by cervical dilation of at least 5 cm on admission to the labor ward [37 (9.3%) vs 28 (5.1%), p = .013)] and with premature rupture of membranes [82 (20.6%) vs 60 (11.0%), p < .001)], and consequently with more admissions to the delivery room [198 (49.7%) vs 189 (34.7%), p < .001)]. We also recorded a significant increase in urgent obstetrical events in the emergency department during the recorded COVID-19 pandemic [23 (5.8%) vs 12 (2.2%)), p = .004]. However, the rates of neonatal and maternal morbidity did not change. During the outbreak the proportion of visits during the night was higher than during the matched period of the previous year: [138 (34.7%) vs 145 (26.6%)), p = .008]. In a multivariate logistic regression, the higher rates of admission to the delivery room during active labor and of urgent events during the pandemic outbreak compared to the matched period in the previous year remained statistically significant.

CONCLUSIONS

The pandemic outbreak of COVID-19 caused a behavioral change among women who presented to the obstetrical emergency department. This was characterized by delayed arrival to the obstetrical emergency department and the delivery room, which led to a significant increase in urgent and acute interventions. The change in behavior did not affect the rates of maternal and neonatal morbidity.

Duration of labor induction in nulliparous women with hypertensive disorders of pregnancy and maternal and neonatal outcomes

OBJECTIVE

The objective of this study was to quantify the association between duration of labor induction in nulliparous women with hypertensive disorders of pregnancy and maternal and neonatal morbidity.

METHODS

This was a secondary analysis of a multicenter cohort study of 228,438 deliveries in 19 U.S. hospitals. The analysis included nulliparous women ≥18 years old with singleton gestation diagnosed with hypertensive disorders of pregnancy and undergoing induction of labor for that indication. Duration of labor induction, defined as time from admission to delivery, was examined by 4 h intervals from <12 h to ≥24 h in relation to maternal and neonatal composite outcomes. Maternal composite outcome included operative vaginal delivery, chorioamnionitis, blood transfusion, intensive care unit admission, placental abruption, 3rd or 4th degree perineal laceration, endometritis, postpartum hemorrhage, or venous thromboembolism. Neonatal composite outcome included neonatal intensive care unit (NICU) admission, respiratory distress syndrome, 5-minute Apgar score ≤7, seizure, infection, intrapartum meconium aspiration, intracranial hemorrhage, shoulder dystocia, and neonatal death. The trends in proportions of outcomes that occurred at different intervals were examined by Cochran-Armitage trend test. Relative risks were calculated with <12 h as the reference category and potential confounders adjusted by log-binomial or Poisson regression. Possible correlations within centers were taken into account using generalized estimating equations.

RESULTS

A total of 3,990 women met inclusion criteria. The median labor duration was 19.8 h (interquartile range 12.9 h-27.9h), with 849 (21.3%) lasting <12 h and 1,426 (35.7%) >24 h. The frequency of composite maternal outcome was not associated with labor duration; however, the rates of chorioamnionitis (p < .001) and postpartum hemorrhage (p < .001) increased as labor duration increased. The frequency of composite neonatal outcome was greater with increasing labor duration (p < .001). After multivariable adjustment, duration of labor induction was associated with increased risks of maternal composite outcome after 24 h (aRR 1.39, 95% CI 1.20-1.62) and neonatal composite outcome after 24 h (aRR 1.32, 95% CI 1.11-1.56).

CONCLUSIONS

In nulliparous women with hypertensive disorders of pregnancy, duration of labor induction was associated with increased risks for maternal and neonatal morbidity after 24 h.

Differential effects of different delivery methods on progression to severe postpartum hemorrhage between Chinese nulliparous and multiparous women: a retrospective cohort study

BACKGROUND

Delivery methods are associated with postpartum hemorrhage (PPH) both in nulliparous and multiparous women. However, few studies have examined the difference in this association between nulliparous and multiparous women. This study aimed to explore the difference of maternal and neonatal characteristics and delivery methods between Chinese nulliparous and multiparous women, and then examine the differential effects of different delivery methods on PPH between these two-type women.

METHODS

Totally 151,333 medical records of women who gave birth between April 2013 to May 2016 were obtained from the electronic health records (EHR) in a northern province, China. The severity of PPH was estimated and classified into blood loss at the level of < 900 ml, 900-1500 ml, 1500-2100 ml, and > 2100 ml. Neonatal and maternal characteristics related to PPH were derived from the same database. Multiple ordinal logistic regression was used to estimate associations.

RESULTS

Medical comorbidities, placenta previa and accreta were higher in the nulliparous group and the episiotomy rate was higher in the multiparous group. Compared with spontaneous vaginal delivery (SVD), the adjusted odds (aOR) for progression to severe PPH due to the forceps-assisted delivery was much higher in multiparous women (aOR: 9.32; 95% CI: 3.66-23.71) than in nulliparous women (aOR: 1.70; 95% CI: 0.91-3.18). The (aOR) for progression to severe PPH due to cesarean section (CS) compared to SVD was twice as high in the multiparous women (aOR: 4.32; 95% CI: 3.03-6.14) as in the nulliparous women (aOR: 2.04; 95% CI: 1.40-2.97). However, the (aOR) for progression to severe PPH due to episiotomy compared to SVD between multiparous (aOR: 1.24; 95% CI: 0.96-1.62) and nulliparous women (aOR: 1.55; 95% CI: 0.92-2.60) was not significantly different. The (aOR) for progression to severe PPH due to vacuum-assisted delivery compared to SVD in multiparous women (aOR: 2.41; 95% CI: 0.36-16.29) was not significantly different from the nulliparous women (aOR: 1.05; 95% CI: 0.40-2.73).

CONCLUSIONS

Forceps-assisted delivery and CS methods were found to increase the risk of severity of the PPH. The adverse effects were even greater for multiparous women. Episiotomy and the vacuum-assisted delivery, and SVD were similar to the risk of progression to severe PPH in either nulliparous or multiparous women. Our findings have implications for the obstetric decision on the choice of delivery methods, maternal and neonatal health care, and obstetric quality control.

Contractile function of the cervix plays a role in normal and pathological pregnancy and parturition

The cervix plays an integral part in ensuring the proper timing of pregnancy and parturition. It maintains the fetus within the uterus and protects it from pathogens present in the vaginal canal. The cervix undergoes extensive remodeling during pregnancy and parturition. This process is associated with collagen degradation, an increase in immune cell response and inflammation in the cervix. However, our understanding of the role of cervical smooth muscles and their contribution to cervical remodeling is still lacking. In this paper, we propose that the active contractile function of the cervix influences cervical remodeling during pregnancy and parturition. Contraction of the cervical smooth muscles helps the cervix to remain firm and closed during early pregnancy, while relaxation of the cervical smooth muscles help facilitate cervical dilatation during labor. This contractile function of the cervix can be influenced by endocrine signals, such as estrogen, progesterone, and oxytocin; local paracrine signals, such as inflammatory chemokines and cytokines, as well as extracellular vesicles, such as exosomes and ectosomes; and by pharmacological agents used for cervical ripening and the induction of labor. A deeper understanding of the role of smooth muscles in cervical remodeling can help us elucidate the cellular processes in the cervix during pregnancy and parturition. This can also help in finding critical signaling pathways and therapeutic targets in the cervix that may decrease the rates of premature cervical ripening and preterm birth.

Timing of induction for term prelabor rupture of membranes and intravenous antibiotics

BACKGROUND

Induction of labor usually within 24 hours is recommended for term prelabor rupture of membranes. It is still unclear when within the 24 hours induction of labor for term prelabor rupture of membranes should be initiated. Antibiotic prophylaxis for group B Streptococcus is usually recommended for prolonged prelabor rupture of membranes.

OBJECTIVE

The aim of our study was to evaluate whether induction of labor at ≤6 hours from prelabor rupture of membranes with intravenous oxytocin in singleton pregnancies at ≥37 weeks' gestation without regular uterine contractions reduces the administration of intravenous antibiotic agents.

STUDY DESIGN

This was a retrospective cohort study including all women with prelabor rupture of membranes at ≥37 weeks' gestation and without regular uterine contractions in which labor was induced using intravenous oxytocin. Women were divided into 2 groups according to the timing of induction (≤6 hours vs >6 hours after prelabor rupture of membranes).

RESULTS

A total of 166 women with term prelabor rupture of membranes were included, 53 of whom (31.9%) were induced within 6 hours of prelabor rupture of membranes and 113 (68.1%) were induced after 6 hours. There were no differences in demographic characteristics and risk factors for term prelabor rupture of membranes between the 2 groups. Women who underwent induction of labor at ≤6 hours were significantly less exposed to intravenous antibiotic prophylaxis compared with women induced at >6 hours (36% vs 80.5%, respectively; odds ratio, 0.14; 95% confidence interval, 0.07-0.28). Furthermore, for women induced within 6 hours after prelabor rupture of membranes, the chances of delivering at <12 or <24 hours were increased, nonreassuring cardiotocogram significantly less common, and hospital stay significantly shorter. No differences were found in regard to neonatal outcomes.

CONCLUSION

Induction of labor at ≤6 hours with intravenous oxytocin after term prelabor rupture of membranes is significantly associated with lesser use of antibiotic agents, shorter latency to delivery, lower incidence of nonreassuring cardiotocogram, and shorter hospital stay than induction of labor at >6 hours after prelabor rupture of membranes.

Association Between Time of Day and the Decision for an Intrapartum Cesarean Delivery

OBJECTIVE

To examine whether the decision and indications for performing intrapartum cesarean delivery vary by time of day.

METHODS

We conducted a secondary analysis of a multicenter observational cohort of 115,502 deliveries (2008-2011), including nulliparous women with term, singleton, nonanomalous live gestations in vertex presentation who were attempting labor. Those who attempted home birth, or underwent cesarean delivery scheduled or decided less than 30 minutes after admission were excluded. Time of day was defined as cesarean delivery decision time among those who delivered by cesarean and delivery time among those who delivered vaginally, categorized by each hour of a 24-hour day. Primary outcomes were decision to perform cesarean delivery and the indications for cesarean delivery (labor dystocia, nonreassuring fetal status, or other indications). Secondary outcomes included whether a dystocia indication adhered to standards promoted to reduce cesarean delivery rates. Bivariate analyses were performed using χ and Kruskal-Wallis tests for categorical and continuous outcomes, respectively, and generalized additive models with smoothing splines explored nonlinear associations without adjustment for other factors.

RESULTS

Seven thousand nine hundred fifty-six (22.1%) of 36,014 eligible women underwent cesarean delivery. Decision for cesarean delivery (P<.001) decreased from midnight (21.2%) to morning, reaching a nadir at 10:00 (17.9%) and subsequently rising to peak at 21:00 (26.2%). The frequency of cesarean delivery for dystocia also was significantly associated with time of day (P<.001) in a pattern mirroring overall cesarean delivery. Among cesarean deliveries for dystocia (n=5,274), decision for cesarean delivery at less than 5 cm dilation (P<.001), median duration from 5 cm dilation to cesarean delivery decision (P=.003), and median duration from complete dilation to cesarean delivery decision (P=.014) all significantly differed with time of day. The frequency of nonreassuring fetal status and "other" indications were not significantly associated with time of day (P>.05).

CONCLUSION

Among nulliparous women who were attempting labor at term, the decision to perform cesarean delivery, particularly for dystocia, varied with time of day. Some of these differences correlate with labor management differences, given the changing frequency of latent phase cesarean delivery and median time in active phase.

Prelabor Rupture of Membranes: ACOG Practice Bulletin, Number 217

Preterm birth occurs in approximately 10% of all births in the United States and is a major contributor to perinatal morbidity and mortality (). Prelabor rupture of membranes (PROM) that occurs preterm complicates approximately 2-3% of all pregnancies in the United States, representing a significant proportion of preterm births, whereas term PROM occurs in approximately 8% of pregnancies (). The optimal approach to assessment and treatment of women with term and preterm PROM remains challenging. Management decisions depend on gestational age and evaluation of the relative risks of delivery versus the risks (eg, infection, abruptio placentae, and umbilical cord accident) of expectant management when pregnancy is allowed to progress to a later gestational age. The purpose of this document is to review the current understanding of this condition and to provide management guidelines that have been validated by appropriately conducted outcome-based research when available. Additional guidelines on the basis of consensus and expert opinion also are presented. This Practice Bulletin is updated to include information about diagnosis of PROM, expectant management of PROM at term, and timing of delivery for patients with preterm PROM between 34 0/7 weeks of gestation and 36 6/7 weeks of gestation.

Cervical Ripening and Labor Induction and Augmentation, 5th Edition

Cervical ripening and induction and augmentation of labor are common procedures in labor and birth units. The potential risks and benefits for the procedure should be explained to women so that they can make informed decisions. Clinicians should be knowledgeable about the methods and medications used and be skilled in maternal-fetal assessment. Adequate nurse staffing is required to monitor the mother and fetus to promote the best possible outcomes. This practice monograph includes information on mechanical and pharmacologic methods for cervical ripening; labor induction and augmentation with oxytocin, a high alert drug; and nurse staffing levels and skills needed to provide safe and effective care during cervical ripening and labor induction and augmentation.

Evidence-based labor management: induction of labor (part 2)

Induction of labor is indicated for many obstetrical, maternal, and fetal indications. Induction can be offered for pregnancy at 39 weeks' gestation. No prediction method is considered sensitive or specific enough to determine the incidence of cesarean delivery after induction. A combination of 60- to 80-mL single-balloon Foley catheter for 12 hours and either 25-μg oral misoprostol initially, followed by 25 μg every 2-4 hours, or 50 μg every 4-6 hours (if no more than 3 contractions per 10 minutes or previous uterine surgery), or oxytocin infusion should be recommended for induction of labor. Adding membrane stripping at the beginning of induction should be considered. Once 5-6 cm of cervical dilation is achieved during the induction of labor, consideration can be given to discontinue oxytocin infusion if in use at that time and adequate contractions are present. Induction with oxytocin immediately (as soon as feasible) or up to 12 hours of term prelabor rupture of membranes if labor is not evident is recommended. Outpatient Foley ripening can be considered for low-risk women. Cesarean delivery should not be performed before 15 hours of oxytocin infusion and amniotomy if feasible and ideally after 18-24 hours of oxytocin infusion.

Induction of labor in continuing pregnancies

This chapter aims to provide an evidence-based approach to cervical-ripening methods and induction of labor in high-, middle-, and low-income countries. We will review the epidemiology of induction and will also review pharmacological and mechanical methods of cervical-ripening as well as oxytocin for induction. Lastly, we will review current guidelines of when to determine an induction to be failed.

"I guess baby was just too comfy in there…": A qualitative study of women's experiences of elective late-term induction of labour

BACKGROUND

The frequency of induction of labour (IOL) in late-term pregnancy has increased significantly, but little is known about how women with uncomplicated pregnancies experience IOL for late-term indication alone.

AIM

To explore how women with uncomplicated pregnancies experienced late-term IOL.

METHODS

Qualitative interviews were conducted with 23 women who all had labour induced on late-term indication only. Participants were recruited from two Danish hospitals who offered an outpatient induction regime. The women were interviewed 4-8 weeks after birth. Data were analysed using thematic analysis.

RESULTS

All women had hoped for a spontaneous birth. Prolonged pregnancy was understood as the body/baby "not being ready", but generally, the women were not worried at that point. Most women felt adequately informed about the reasons for IOL, but some requested more information and time to consider their options. The majority considered IOL to be both an offer and a recommendation. One-third of the participants were initially hesitant but chose/accepted IOL because of weariness from pregnancy and the impatience to deliver a healthy child. The opportunity of outpatient induction was generally appreciated as it allowed the women to continue everyday activities while waiting for labour to begin. Nineteen women reported having a good birthing experience. Two women felt that negative birthing experiences were partly related to IOL.

CONCLUSIONS

Most women considered the late-term IOL to be a positive experience. Some women requested more information and time to consider alternatives. These women should be provided with supported opportunities to consider the options.

Balloon catheter use for cervical ripening in women with term pre-labor rupture of membranes: A 5-year cohort study

INTRODUCTION

To investigate the safety of balloon catheter for cervical ripening in women with term pre-labor rupture of membranes (PROM) and to compare the incidence of maternal and neonatal infections in women with PROM and women with intact membranes undergoing cervical ripening with a balloon catheter.

MATERIAL AND METHODS

This retrospective cohort study of 1923 women with term singleton pregnancy and an unfavorable cervix undergoing cervical ripening with a balloon catheter was conducted in Helsinki University Hospital between January 2014 and December 2018. For each case of PROM, two controls were assigned. The main outcome measures were the rates of maternal and neonatal infections. Statistical analyses were performed by SPSS.

RESULTS

In all, 641 (33.3%) women following PROM and 1282 (66.6%) women with intact amniotic membranes underwent labor induction. The rates of intrapartum infection (3.7% vs 7.7%; P = .001) and neonatal infection (1.7% vs 3.8%; P = .01) were not increased in women induced by balloon catheter following PROM. Intrapartum infections were associated with nulliparity (odds ratio [OR] 3.3, 95% confidence interval [CI] 1.6-6.5), history of previous cesarean section (OR 2.8, 95% CI 1.2-6.4), extended gestational age ≥41 weeks (OR 1.9, 95% CI 1.2-3.0) and an induction to delivery interval of 48 hours or more (OR 2.0, 95% CI 1.2-3.3). The risk of neonatal infection was associated with nulliparity (OR 3.3, 95% CI 1.4-8.0), gestational age ≥41 weeks (OR 1.9, 95% CI 1.09-3.36) and induction to delivery interval of 48 hours or more (OR 3.4, 95% CI 1.9-6.0).

CONCLUSIONS

Use of balloon catheter in women with term PROM appears safe and was not associated with increased maternal or neonatal infectious morbidity.

Uterine balloon tamponade for the treatment of postpartum hemorrhage: a systematic review and meta-analysis

OBJECTIVE

To assess the efficacy, effectiveness, and safety of uterine balloon tamponade for treating postpartum hemorrhage.

STUDY DESIGN

We searched electronic databases (from their inception to August 2019) and bibliographies. We included randomized controlled trials, nonrandomized studies, and case series that reported on the efficacy, effectiveness, and/or safety of uterine balloon tamponade in women with postpartum hemorrhage. The primary outcome was the success rate of uterine balloon tamponade for treating postpartum hemorrhage (number of uterine balloon tamponade success cases/total number of women treated with uterine balloon tamponade). For meta-analyses, we calculated pooled success rate for all studies, and relative risk with 95% confidence intervals for studies that included a comparative arm.

RESULTS

Ninety-one studies, including 4729 women, met inclusion criteria (6 randomized trials, 1 cluster randomized trial, 15 nonrandomized studies, and 69 case series). The overall pooled uterine balloon tamponade success rate was 85.9% (95% confidence interval, 83.9-87.9%). The highest success rates corresponded to uterine atony (87.1%) and placenta previa (86.8%), and the lowest to placenta accreta spectrum (66.7%) and retained products of conception (76.8%). The uterine balloon tamponade success rate was lower in cesarean deliveries (81.7%) than in vaginal deliveries (87.0%). A meta-analysis of 2 randomized trials that compared uterine balloon tamponade vs no uterine balloon tamponade in postpartum hemorrhage due to uterine atony after vaginal delivery showed no significant differences between the study groups in the risk of surgical interventions or maternal death (relative risk, 0.59; 95% confidence interval, 0.02-16.69). A meta-analysis of 2 nonrandomized before-and-after studies showed that introduction of uterine balloon tamponade in protocols for managing severe postpartum hemorrhage significantly decreased the use of arterial embolization (relative risk, 0.29; 95% confidence interval, 0.14-0.63). A nonrandomized cluster study reported that use of invasive procedures was significantly lower in the perinatal network that routinely used uterine balloon tamponade than that which did not use uterine balloon tamponade (3.0/1000 vs 5.1/1000; P < .01). A cluster randomized trial reported that the frequency of postpartum hemorrhage-related invasive procedures and/or maternal death was significantly higher after uterine balloon tamponade introduction than before uterine balloon tamponade introduction (11.6/10,000 vs 6.7/10,000; P = .04). Overall, the frequency of complications attributed to uterine balloon tamponade use was low (≤6.5%).

CONCLUSION

Uterine balloon tamponade has a high success rate for treating severe postpartum hemorrhage and appears to be safe. The evidence on uterine balloon tamponade efficacy and effectiveness from randomized and nonrandomized studies is conflicting, with experimental studies suggesting no beneficial effect, in contrast with observational studies. Further research is needed to determine the most effective programmatic and healthcare delivery strategies on uterine balloon tamponade introduction and use.

Metabolic Pathways Associated With Term Labor Induction Course in African American Women

OBJECTIVES

The purpose of this study was to evaluate differences in the metabolic pathways activated in late-pregnancy serum samples among African American women who went on to have term (≥37 weeks) labor induction requiring high total oxytocin doses to complete first-stage labor compared to those in similar women with low-oxytocin labor inductions.

STUDY DESIGN

Case-control study (N = 27 women with labor induction with successful cervical ripening: 13 requiring the highest total doses of synthetic oxytocin to progress from 4- to 10-cm cervical dilation and 14 requiring the lowest total doses) with groups balanced on parity and gestational age. Serum samples obtained between 24 and 30 weeks' gestation were analyzed using ultra-high-resolution metabolomics. Differentially expressed metabolites between high-oxytocin induction cases and low-oxytocin induction comparison subjects were evaluated using linear regression with xmsPANDA. Metabolic pathways analysis was conducted using Mummichog Version 2.0, with discriminating metabolites annotated using xMSannotator Version 1.3.

RESULTS

Labor processes were similar by group with the exception that cases received over 6 times more oxytocin between 4- and 10-cm cervical dilation than comparison women. Induction requiring high total doses of synthetic oxytocin was associated with late-pregnancy serum levels of metabolites from the linoleate and fatty acid activation pathways in term, African American women.

CONCLUSION

Serum levels of several lipid metabolites predicted more complicated labor induction involving higher doses of synthetic oxytocin to complete first-stage labor. Further investigation in larger, more diverse cohorts of women is needed to identify potential targets to prevent failed labor 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.

Induction of labor compared to expectant management in term nulliparas with a latent phase of labor of more than 8 hours: a randomized trial

Background

Prolonged latent phase of labor is associated with adverse maternal and neonatal outcomes. Preliminary data indicate that labor induction for prolonged latent phase may reduce cesarean delivery. We performed a study powered to Cesarean delivery to evaluate labor induction compared to expectant management in full term nulliparas hospitalized for persistent contractions but non-progressive to established labor after an overnight stay.

Methods

From 2015 and 2017, nulliparas, ≥ 39 weeks’ gestation with prolonged latent phase of labor (persistent contractions after overnight hospitalization > 8 h), cervical dilation ≤3 cm, intact membranes and reassuring cardiotocogram were recruited. Participants were randomized to immediate induction of labor (with vaginal dinoprostone or amniotomy or oxytocin as appropriate) or expectant management (await labor for at least 24 h unless indicated intervention as directed by care provider). Primary outcome measure was Cesarean delivery.

Results

Three hundred eighteen women were randomized (159 to each arm). Data from 308 participants were analyzed. Cesarean delivery rate was 24.2% (36/149) vs. 23.3%, (37/159) RR 1.0 95% CI 0.7–1.6; P = 0.96 in induction of labor vs. expectant arms. Interval from intervention to delivery was 17.1 ± 9.9 vs. 40.1 ± 19.8 h; P < 0.001, intervention to active labor 9.6 ± 10.2 vs. 29.6 ± 18.5 h; P < 0.001, active labor to delivery 7.6 ± 3.6 vs. 10.5 ± 7.2 h; P < 0.001, intervention to hospital discharge 2.4 ± 1.2 vs. 2.9 ± 1.4 days; P < 0.001 and dinoprostone use was 19.5% (29/149) vs. 8.2% (13/159) RR 2.4 95% CI 1.3–4.4; P = 0.01 in IOL compared with expectant arms respectively. Intrapartum oxytocin use, epidural analgesia and uterine hyperstimulation syndrome, postpartum hemorrhage, patient satisfaction on allocated intervention, during labor and delivery and baby outcome were not significantly different across trial arms.

Conclusions

Induction of labor did not reduce Cesarean delivery rates but intervention to delivery and to hospital discharge durations are shorter. Patient satisfaction scores were similar. Induction of labor for prolonged latent phase of labor can be performed without apparent detriment to expedite delivery.

Trial registration

Registered in Malaysia National Medical Research Register (NMRR-15-16-23,886) on 6 January 2015 and the International Standard Randomised Controlled Trials Number registry, registration number ISRCTN14099170 on 5 Nov 2015.

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.

The transition from latent to active labor and adverse obstetrical outcomes

BACKGROUND

Recommendations on preventing primary cesarean delivery removed the previously defined time limits for latent labor (defined as ending at 6 cm) and urged clinicians to avoid cesarean delivery for labor abnormalities in the latent phase. However, relatively little is known about the implications of labor curve abnormalities from 4 to 6 cm and subsequent outcomes.

OBJECTIVE

To examine the association between length of time for dilation from 4 to 6 cm, delivery outcomes, and maternal and neonatal morbidity.

STUDY DESIGN

This is a secondary analysis of a prospective cohort study of patients at ≥37 weeks presenting in spontaneous or induced labor with a nonanomalous living singleton in vertex presentation. Patients with a history of cesarean delivery or who did not achieve 6-cm dilation were excluded. We used interval censored regression to determine the 90th percentile for dilation time from 4 to 6 cm and used logistic regression to estimate the odds ratios and 95% confidence intervals for adverse outcomes for patients above this cutoff percentile compared with those at or below. Analyses were adjusted for obesity, nulliparity, race, hypertension, diabetes, and type of labor (induced vs spontaneous/augmented). Outcomes included cesarean delivery, maternal morbidity (composite of postpartum fever, wound infection, hemorrhage), and neonatal morbidity (composite of neonatal death, hypothermic therapy, mechanical ventilation, respiratory distress, meconium aspiration syndrome, seizure, or treatment of sepsis). In addition, we created receiver operator characteristic curves to predict cesarean delivery, and maternal and neonatal morbidity based on time to dilate from 4 to 6 cm. The cutoff for time for each outcome was identified using the Youden index to maximize sensitivity and specificity, and test characteristics were computed.

RESULTS

There were 7355 patients eligible for analysis, 728 (10%) had dilation times from 4 to 6 cm >10.3 hours, which was the 90th percentile, and 6627 (90%) had dilation times ≤10.3 hours. Having dilation time from 4 to 6 cm above the 90th percentile (10.3 hours) was associated with cesarean delivery (adjusted odds ratio, 2.05; 95% confidence interval, 1.67-2.52), composite maternal morbidity (adjusted odds ratio, 1.48; 95% confidence interval, 1.10-2.00), and composite neonatal morbidity (adjusted odds ratio 1.92; 95% confidence interval 1.52-2.4). The area under the receiver operator characteristic curve for predicting cesarean delivery was 0.73 (95% confidence interval, 0.71-0.75). The test characteristics for the cutoff of 9.75 hours were sensitivity 68.3% (95% confidence interval, 64.8%-71.7%), specificity 66.2% (95% confidence interval, 55.0%-67.3%), positive predictive value 18.5% (95% confidence interval, 17.1%-20.0%), and negative predictive value 94.9% (95% confidence interval, 94.2%-95.5%). For composite maternal morbidity, the cutoff was 6.98 hours and the area under the curve was 0.62 (95% confidence interval, 0.59-0.65), whereas for composite neonatal morbidity it was 5.5 hours (area under the curve 0.69; 95% confidence interval, 0.67-0.71).

CONCLUSIONS

Patients whose dilation time from 4 to 6 cm exceeds the 90th percentile have increased odds of cesarean delivery and postpartum complications. Prolonged dilation time has moderate predictive ability for adverse outcomes. Future studies should investigate at what point, if any, intervention is warranted during this period to reduce these risks.