Normal Progress of Induced Labor:

Risks Associated with Prolonged Latent Phase of Labor

We sought to assess the impact of a prolonged latent phase (PLP) on maternal and neonatal morbidity.This is a secondary analysis of a prospective cohort study conducted 2010 to 2015 that included all term gravidas who reached active labor (6 cm). Primary outcomes were composite maternal morbidity (maternal fever, postpartum hemorrhage, transfusion, endometritis, and severe perineal lacerations) and composite neonatal morbidity (respiratory distress syndrome, mechanical ventilation, birth injury, seizures, hypoxic ischemic encephalopathy, therapeutic hypothermia, or umbilical artery pH ≤ 7.1). Outcomes were compared between patients with and without PLP, defined as ≥90th percentile of labor duration between admission and active phase. Results were stratified by induction of labor (IOL) versus spontaneous labor. A stratified analysis was performed by mode of delivery. Multivariable logistic regression was used to adjust for confounders.In this cohort of 6,509 patients, 51% underwent IOL. A total of 650 patients had a PLP with a median length of 8.5 hours in spontaneous labor and 18.8 hours in IOL. Among patients with PLP, there was a significant increase in composite maternal morbidity with both IOL (adjusted odds ratio [aOR]: 1.36, 95% confidence interval [CI]: 1.01, 1.84) and spontaneous labor (aOR: 1.49, 95% CI: 1.09, 2.04) and an increase in composite neonatal morbidity with spontaneous labor only (aOR: 1.57, 95% CI: 1.01, 2.45). Cesarean delivery occurred more often in PLP group (14.0 vs. 25.1%). Among patients who underwent cesarean delivery, PLP remained associated with increased odds of maternal morbidity compared with those with normal latent phase.PLP at or above the 90th percentile in patients who reach active labor is associated with increased risk of maternal morbidity that is not mediated by cesarean delivery. PLP in spontaneous labor is associated with increased neonatal morbidity. These data suggest that further research is needed to establish latent phase cut-offs that may be incorporated into labor management guidelines. · Latent labor ≥90th percentile is associated with increased maternal morbidity in induced and spontaneous labor.. · Latent labor ≥90th percentile in spontaneous but not induced labor is associated with increased neonatal morbidity.. · Cesarean delivery alone does not explain this increased maternal morbidity..

Pregnancy state before the onset of labor: a holistic mechanical perspective

Successful pregnancy highly depends on the complex interaction between the uterine body, cervix, and fetal membrane. This interaction is synchronized, usually following a specific sequence in normal vaginal deliveries: (1) cervical ripening, (2) uterine contractions, and (3) rupture of fetal membrane. The complex interaction between the cervix, fetal membrane, and uterine contractions before the onset of labor is investigated using a complete third-trimester gravid model of the uterus, cervix, fetal membrane, and abdomen. Through a series of numerical simulations, we investigate the mechanical impact of (i) initial cervical shape, (ii) cervical stiffness, (iii) cervical contractions, and (iv) intrauterine pressure. The findings of this work reveal several key observations: (i) maximum principal stress values in the cervix decrease in more dilated, shorter, and softer cervices; (ii) reduced cervical stiffness produces increased cervical dilation, larger cervical opening, and decreased cervical length; (iii) the initial cervical shape impacts final cervical dimensions; (iv) cervical contractions increase the maximum principal stress values and change the stress distributions; (v) cervical contractions potentiate cervical shortening and dilation; (vi) larger intrauterine pressure (IUP) causes considerably larger stress values and cervical opening, larger dilation, and smaller cervical length; and (vii) the biaxial strength of the fetal membrane is only surpassed in the cases of the (1) shortest and most dilated initial cervical geometry and (2) larger IUP.

The effects of intravenous hydration regimens in nulliparous women undergoing induction of labor: A systematic review and meta-analysis

INTRODUCTION

Labor is both a physiological and physical activity that requires energy expenditure by the woman. Despite this, women are often fasted in labor, with hydration requirements addressed predominantly by intravenous therapy. Little is known about how best to manage this in nulliparous women undergoing induction of labor, who can be prone to lengthy labors. Therefore, we undertook a systematic review and meta-analysis to determine the effects of intravenous hydration regimens on nulliparous women undergoing induction of labor.

MATERIAL AND METHODS

A systematic review and meta-analysis were conducted. Databases searched were PubMed, CINAHL, Embase, Cochrane, Scopus, and Web of Science using the search strategy combination of associated key concepts for intravenous therapy and nulliparous laboring women. The primary outcome was excessive neonatal weight loss. Meta-analyses for categorical outcomes included estimates of odds ratio (OR) and their 95% confidence intervals (CI) calculated; and for continuous outcomes the standardized mean difference, each with its 95% CI. Heterogeneity was assessed visually and by using the χ2 statistic and I2 with significance being set at p < 0.10.

RESULTS

A total of 1512 studies were located and following screening, three studies met the eligibility criteria. No studies reported excessive neonatal weight loss. Increased rates of intravenous therapy (250 mL/h vs. 125 mL/h) during labor were not found to reduce the overall length of labor (mean difference -0.07 h, 95% CI -0.27 to 0.13 h) or reduce cesarean sections (OR 0.74, 95% CI 0.45-1.23), when women were not routinely fasted.

CONCLUSIONS

Our review found no significant improvements for nulliparous women who received higher intravenous fluid volumes when undergoing induction of labor and were not routinely fasted. However, data are limited, and further research is needed.

New labor curves of dilation and station to improve the accuracy of predicting labor progress

BACKGROUND

The diagnosis of failure to progress, the most common indication for intrapartum cesarean delivery, is based on the assessment of cervical dilation and station over time. Labor curves serve as references for expected changes in dilation and fetal descent. The labor curves of Friedman, Zhang et al, and others are based on time alone and derived from mothers with spontaneous labor onset. However, labor induction is now common, and clinicians also consider other factors when assessing labor progress. Labor curves that consider the use of labor induction and other factors that influence labor progress have the potential to be more accurate and closer to clinical decision-making.

OBJECTIVE

This study aimed to compare the prediction errors of labor curves based on a single factor (time) or multiple clinically relevant factors using two modeling methods: mixed-effects regression, a standard statistical method, and Gaussian processes, a machine learning method.

STUDY DESIGN

This was a longitudinal cohort study of changes in dilation and station based on data from 8022 births in nulliparous women with a live, singleton, vertex-presenting fetus ≥35 weeks of gestation with a vaginal delivery. New labor curves of dilation and station were generated with 10-fold cross-validation. External validation was performed using a geographically independent group. Model variables included time from the first examination in the 20 hours before delivery; dilation, effacement, and station recorded at the previous examination; cumulative contraction counts; and use of epidural anesthesia and labor induction. To assess model accuracy, differences between each model's predicted value and its corresponding observed value were calculated. These prediction errors were summarized using mean absolute error and root mean squared error statistics.

RESULTS

Dilation curves based on multiple parameters were more accurate than those derived from time alone. The mean absolute error of the multifactor methods was better (lower) than those of the single-factor methods (0.826 cm [95% confidence interval, 0.820-0.832] for the multifactor machine learning and 0.893 cm [95% confidence interval, 0.885-0.901] for the multifactor mixed-effects method and 2.122 cm [95% confidence interval, 2.108-2.136] for the single-factor methods; P<.0001 for both comparisons). The root mean squared errors of the multifactor methods were also better (lower) than those of the single-factor methods (1.126 cm [95% confidence interval, 1.118-1.133] for the machine learning [P<.0001] and 1.172 cm [95% confidence interval, 1.164-1.181] for the mixed-effects methods and 2.504 cm [95% confidence interval, 2.487-2.521] for the single-factor [P<.0001 for both comparisons]). The multifactor machine learning dilation models showed small but statistically significant improvements in accuracy compared to the mixed-effects regression models (P<.0001). The multifactor machine learning method produced a curve of descent with a mean absolute error of 0.512 cm (95% confidence interval, 0.509-0.515) and a root mean squared error of 0.660 cm (95% confidence interval, 0.655-0.666). External validation using independent data produced similar findings.

CONCLUSION

Cervical dilation models based on multiple clinically relevant parameters showed improved (lower) prediction errors compared to models based on time alone. The mean prediction errors were reduced by more than 50%. A more accurate assessment of departure from expected dilation and station may help clinicians optimize intrapartum management.

Evidence-based guidelines for intrapartum maternal hydration assessment and management: A scoping review

PROBLEM

Inconsistent practice relating to intrapartum hydration assessment and management is reported, and potential harm exists for laboring women and birthing persons.

BACKGROUND

Labor and birth are physically demanding, and adequate nutrition and hydration are essential for labor progress. A lack of clear consensus on intrapartum hydration assessment and management during labor and birth currently exists. In addition, there is an inconsistent approach to managing hydration, often including a mixture of intravenous and oral fluids that are poorly monitored.

AIM

The aim of this scoping review was to identify and collate evidence-based guidelines for intrapartum hydration assessment and management of maternal hydration during labor and birth.

METHODS

PubMed, Embase, and CINAHL databases were searched, in addition to professional college association websites. Inclusion criteria were intrapartum clinical guidelines in English, published in the last 10 years.

FINDINGS

Despite searching all appropriate databases in maternity care, we were unable to identify evidence-based guidelines specific to hydration assessment and management, therefore resulting in an "empty review." A subsequent review of general intrapartum care guidelines was undertaken. Our adapted review identified 12 guidelines, seven of which referenced the assessment and management of maternal hydration during labor and birth. Three guidelines recommend that "low-risk" women in spontaneous labor at term should hold determination over what they ingest in labor. No recommendations with respect to assessment and management of hydration for women undergoing induction of labor were found.

DISCUSSION

Despite the increasing use of intravenous fluid as an adjunct to oral intake to maintain maternal intrapartum hydration, there is limited evidence and, subsequently, guidelines to determine best practice in this area. How hydration is assessed was also largely absent from general intrapartum care guidelines, further perpetuating potential clinical variation in this area.

CONCLUSION

There is an absence of guidelines specific to the assessment and management of maternal hydration during labor and birth, despite its importance in ensuring labor progress and safe care.

Labor curves based on cervical dilatation over time and their accuracy and effectiveness: A systematic scoping review

OBJECTIVES

This systematic scoping review was conducted to 1) identify and describe labor curves that illustrate cervical dilatation over time; 2) map any evidence for, as well as outcomes used to evaluate the accuracy and effectiveness of the curves; and 3) identify areas in research that require further investigation.

METHODS

A three-step systematic literature search was conducted for publications up to May 2023. We searched the Medline, Maternity & Infant Care, Embase, Cochrane Library, Epistemonikos, CINAHL, Scopus, and African Index Medicus databases for studies describing labor curves, assessing their effectiveness in improving birth outcomes, or assessing their accuracy as screening or diagnostic tools. Original research articles and systematic reviews were included. We excluded studies investigating adverse birth outcomes retrospectively, and those investigating the effect of analgesia-related interventions on labor progression. Study eligibility was assessed, and data were extracted from included studies using a piloted charting form. The findings are presented according to descriptive summaries created for the included studies.

RESULTS AND IMPLICATIONS FOR RESEARCH

Of 26,073 potentially eligible studies, 108 studies were included. Seventy-three studies described labor curves, of which ten of the thirteen largest were based mainly on the United States Consortium on Safe Labor cohort. Labor curve endpoints were 10 cm cervical dilatation in 69 studies and vaginal birth in 4 studies. Labor curve accuracy was assessed in 26 studies, of which all 15 published after 1986 were from low- and middle-income countries. Recent studies of labor curve accuracy in high-income countries are lacking. The effectiveness of labor curves was assessed in 13 studies, which failed to prove the superiority of any curve. Patient-reported health and well-being is an underrepresented outcome in evaluations of labor curves. The usefulness of labor curves is still a matter of debate, as studies have failed to prove their accuracy or effectiveness.

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.

Comparison of Labor Curves Between Spontaneous and Induced Labor

OBJECTIVE

To compare the labor curve between individuals with induced labor and those undergoing spontaneous labor.

METHODS

This was a secondary analysis of the Consortium on Safe Labor database, including nulliparous and multiparous individuals with singleton vertex pregnancy who delivered vaginally after spontaneous labor or induction of labor at term. Labor that resulted in uterine rupture and neonates with a 5-minute Apgar scores less than 7, birth injury, or neonatal intensive care unit admission was excluded. We modeled the course of cervical dilation using repeated-measures analysis with a polynomial function. We compared traverse time , defined as the elapsed time between two given dilation measures, between induced and spontaneous labor using interval-censored regression.

RESULTS

Of 46,835 nulliparous individuals, 18,576 and 28,259 underwent induced and spontaneous labor, respectively. Of 77,503 multiparous individuals, 29,684 and 47,819 underwent induced and spontaneous labor, respectively. The start of the active phase on the labor curve was 6 cm in induced labor, regardless of parity. In nulliparous individuals, induced labor compared with spontaneous labor had a significantly shorter traverse time from 6 to 10 cm (median 1.8 hours [5th-95th percentile 0.4-8.6 hours] vs 2.3 hours [5th-95th percentile 0.6-9.4 hours]; P <.01). In multiparous individuals, induced labor compared with spontaneous labor had a significantly shorter traverse time from 6 to 10 cm (median 0.9 hours [5th-95th percentile 0.1-6.0 hours] vs 1.4 hours [5th-95th percentile 0.3-7.9 hours]; P <.01).

CONCLUSION

Similar to spontaneous labor, the start of the active phase of induced labor was at 6 cm of dilation. Comparatively, induced labor had a shorter active phase than spontaneous labor. These findings suggest that the current criteria for active phase arrest provided by the American College of Obstetricians and Gynecologists do not need to be lengthened for individuals in induced labor.

Is there a difference in labor patterns after induction with prostaglandins and double-balloon catheters?

BACKGROUND

Labor progression curves are believed to differ between spontaneous and induced labors. However, data describing labor progression patterns with different modes of induction are insufficient.

OBJECTIVE

This study aimed to compare the progress patterns between labors induced with slow-release prostaglandin E2 vaginal analogue and those induced with a double-balloon catheter.

STUDY DESIGN

This retrospective cohort study included all nulliparous women who delivered at term and who underwent cervical ripening with prostaglandin E2 vaginal analogue or a double-balloon catheter from 2013 to 2021 in a tertiary hospital in Israel. Included in the analysis were women who achieved 10 cm cervical dilatation. The time intervals between centimeter-to-centimeter changes were evaluated.

RESULTS

A total of 1087 women were included of whom 786 (72.3%) were induced using prostaglandin E2 vaginal analogue and 301 (27.7%) were induced using a double-balloon catheter. The time from induction to birth was similar between the groups (32.5 hours for the prostaglandin E2 vaginal analogue group [5th-95th percentiles, 6.5-153.8] vs 29.2 hours for the double-balloon group [5th-95th percentiles, 9.1-157.1]; P=.100). The median time of the latent phase (2-6 cm dilation) was longer for the double-balloon catheter group than for the prostaglandin E2 vaginal analogue group (7.3 hours [5th-95th percentiles, 5.6-14.5] vs 6.0 hours [5th-95th percentiles, 2.4-18.8]; P=.042). The median time of active labor (6-10 cm dilatation) was similar between groups (1.9 hours [5th-95th percentiles, 0.3-7.4] for the prostaglandin E2 vaginal analogue group vs 2.3 hours [5th-95th percentiles, 0.3-6.5] for the double-balloon catheter group; P=.307).

CONCLUSION

Deliveries subjected to cervical ripening with a double-balloon catheter were characterized by a slightly longer latent phase than deliveries induced by prostaglandin E2 vaginal analogue. After reaching the active phase of labor, the mode of cervical ripening did not influence the labor progress pattern.

Comparison of Pregnancy Outcome between 4 and 6 cm Cervical os Dilatation to Demarcate Active Phase of Labour: A Cross-Sectional Study

This is a cross-sectional study comparing pregnancy outcomes between participants with 4 and 6 cm of cervical os dilatation at the diagnosis of the active phase of labour. It was conducted in a single tertiary centre involving low-risk singleton pregnancies at or beyond 37 weeks with spontaneous onset of labour. A total of 155 participants were recruited, 101 in group 1 (4 cm) and 54 in group 2 (6 cm). Both groups were similar in mean maternal age, mean gestational age at delivery, ethnicity, median haemoglobin level at delivery, body mass index, and parity. There were significantly more participants in group 1 who needed oxytocin augmentation (p < 0.001) for the longer mean duration (p = 0.015), use of analgesia (p < 0.001), and caesarean section rate (p = 0.002). None of the women had a postpartum haemorrhage or a third- or fourth-degree perineal tear, and none of the neonates required admission to the neonatal intensive care unit. There were significantly more nulliparas who had a caesarean section as compared to multiparas. A cervical os dilatation of 6 cm reduces the risk of caesarean section by 11% (95% CI, 0.01-0.9) and increases three times more the need for analgesia (AOR = 3.44, 95% CI, 1.2-9.4). In conclusion, the demarcation of the active phase of labour at a cervical os dilatation of 6 cm is feasible without an increase in maternal or neonatal complications.

Intrapartum Maternal Fever and Long-Term Infectious Morbidity of the Offspring

Maternal intrapartum fever can lead to various maternal and neonatal complications and is attributed to various etiologies including infectious and non-infectious processes. In this study, we evaluated whether intrapartum fever affects the offspring's tendency to long-term infectious morbidity. A population-based cohort analysis including deliveries between 1991 and 2021 was conducted. The incidence of hospitalizations of the offspring up to the age of 18 years, due to various infectious conditions, was compared between pregnancies complicated by intrapartum fever and those that were not. A Kaplan-Meier survival curve was used to assess cumulative hospitalization incidence. A Cox proportional hazards model was used to control for confounders. Overall, 538 of the 356,356 included pregnancies were complicated with fever. A higher rate of pediatric hospitalizations due to various infectious conditions was found among the exposed group, which was significant for viral, fungal and ENT infections (p < 0.05 for all). The total number of infectious-related hospitalizations was significantly higher (30.1% vs. 24.1%; OR = 1.36; p = 0.001), as was the cumulative incidence of hospitalizations. This association remained significant after controlling for confounders using a Cox proportional hazards model (adjusted HR = 1.21; 95% CI 1.04-1.41, p = 0.016). To conclude, fever diagnosed close to delivery may influence offspring susceptibility to pediatric infections.

Is there an increased risk of cesarean section in obese women after induction of labor? A retrospective cohort study

Background

Obesity is increasing in Sweden and is also of huge global concern. Obesity increases the risk of complications during pregnancy and the need for the induction of labor. Induction of labor increases the number of complications during delivery, leading to women with more negative birth experience. This study investigated how maternal body mass index (BMI) during antenatal care enrollment affects labor outcomes (proportion of cesarean section at induction of labor).

Method

This was a retrospective cohort study of 3772 women with mixed parity and induction of labor at Soderhospital, Stockholm, in 2009–2010 and 2012–2013. The inclusion criteria were simplex, ≥34 gestational weeks, cephalic presentation and no previous cesarean section. The women were grouped according to BMI, and statistical analyzes were performed to compare the proportion of cesarean sections after induction of labor. The primary outcome was the proportion of cesarean section after induction of labor divided by group of maternal BMI. The secondary outcomes were postpartum hemorrhage >1000 ml, time of labor, fetal outcome data, and indication for emergency cesarean section.

Result

The induction of labor in women with a high BMI resulted in a significantly increased risk of cesarean section, with 18.4–24.1% of deliveries, depending on the BMI group. This outcome persisted after adjustment in women with BMI 25–29.9 (aOR 1.4; 95% CI; 1.1–1.7) and BMI 30–34.9 (aOR 1.5; 95% CI; 1.1–2.1). There was also a significantly higher risk for CS among primiparous women (aOR 3.6; 95% CI; 2.9–45) and if the newborn weighted ≥ four kilos (aOR 1.6; 95% CI; 1.3–2.0).

Conclusion

Our findings show that a higher BMI increased the risk of cesarean section after induction of labor in the groups with BMI 25–34.9. Parity seems to be the strongest risk factor for CS regardless other variables.

The influence of maternal psychological distress on the mode of birth and duration of labor: findings from the FinnBrain Birth Cohort Study

Antepartum depression, general anxiety symptoms, and pregnancy-related anxiety have been recognized to affect pregnancy outcomes. Systematic reviews on these associations lack consistent findings, which is why further research is required. We examined the associations between psychological distress, mode of birth, epidural analgesia, and duration of labor. Data from 3619 women with singleton pregnancies, from the population-based FinnBrain Birth Cohort Study were analyzed. Maternal psychological distress was measured during pregnancy at 24 and 34 weeks, using the Pregnancy-Related Anxiety Questionnaire-Revised 2 (PRAQ-R2) and its subscale "Fear of Giving Birth" (FOC), the anxiety subscale of the Symptom Checklist-90 (SCL-90) and the Edinburgh Postnatal Depression Scale (EPDS). Mode of birth, epidural analgesia, and labor duration were obtained from the Finnish Medical Birth Register. Maternal psychological distress, when captured with PRAQ-R2, FOC, and SCL-90, increased the likelihood of women having an elective cesarean section (OR: 1.04, 95% CI 1.01-1.06, p = .003; OR: 1.13, 95% CI 1.07-1.20, p < .001; OR: 1.06, 95% CI 1.03-1.10, p = .001), but no association was detected for instrumental delivery or emergency cesarean section. A rise in both the PRAQ-R2, and FOC measurements increased the likelihood of an epidural analgesia (OR: 1.02, 95% CI 1.01-1.03, p = .003; OR: 1.09, 95% CI 1.05-1.12, p < .001) and predicted longer second stage of labor (OR: 1.01, 95% CI 1.00-1.01, p = .023; OR: 1.03, 95% CI 1.02-1.05, p < .001). EPDS did not predict any of the analyzed outcomes. The results indicate that maternal anxiety symptoms (measured using PRAQ-R2, FOC, and SCL-90) are associated with elective cesarean section. Psychological distress increases the use of epidural analgesia, but is not associated with complicated vaginal birth.

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.

The effect of ultrasonographically measured fetal adipose tissue components on labor

AIM

To investigate whether increased fetal adiposity diagnosed ultrasonographical is associated with labor dystocia, and increased risk of operative delivery.

METHOD

This was a prospective study and included 400 pregnant women between 37 and 41 weeks of gestation. In addition to standard ultrasonographic measurements, we evaluated fetal soft tissue thickness before delivery. We also recorded data on delivery method, shoulder dystocia, fetal birthweight and labor duration. We considered the period between 6 and 10 cm cervical opening as the active phase, and the period from full dilation to birth as the second stage.

RESULTS

While the vaginal delivery rate was 77.3%, a cesarean was performed in 22.7% of pregnant women. We found a positive correlation between fetal adipose tissue components and durations of the active phase and second-stage labor and the baby's birthweight. Also, we examined and determined that cesarean section and labor dystocia increased as the fetus adipose tissue thickness increased. We investigated the effect of parameters on the study results with logistic regression analysis and possible threshold values with receiver operating characteristics analysis.

CONCLUSION

Our study evaluated the fetal adipose tissue complex during delivery was significant in terms of labor dystocia and operative delivery. We think it may be a guide for future studies in the literature.

Association of body mass index and maternal age with first stage duration of labour

To evaluate associations between early-pregnancy body mass index (BMI) and active first stage labour duration, accounting for possible interaction with maternal age, we conducted a cohort study of women with spontaneous onset of labour allocated to Robson group 1. Quantile regression analysis was performed to estimate first stage labour duration between BMI categories in two maternal age subgroups (more and less than 30 years). Results show that obesity (BMI > 30) among younger women (< 30 years) increased the median labour duration of first stage by 30 min compared with normal weight women (BMI < 25), and time difference estimated at the 90th quantile was more than 1 h. Active first stage labour time differences between obese and normal weight women was modified by maternal age. In conclusion: (a) obesity is associated with longer duration of first stage of labour, and (b) maternal age is an effect modifier for this association. This novel finding of an effect modification between BMI and maternal age contributes to the body of evidence that supports a more individualized approach when describing labour duration.

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.

Nursing Support During Latent Phase Labor: A Scoping Review

PURPOSE

The purpose of this scoping review was to synthesize the literature on nursing support during the latent phase of the first stage of labor. In 2014, the definition of the beginning of active labor changed from 4 centimeters (cm) to 6 cm cervical dilation. More women may have an induction of labor based on results of recent research showing no causal increase in risk of cesarean birth with elective induction of labor for low-risk nulliparous women. Therefore, in-hospital latent phase labor may be longer, increasing the need for nursing support.

DESIGN

Scoping review of the literature from 2009 to present.

METHODS

We conducted the review using key words in PubMed, CINAHL, and Scopus. Search terms included different combinations of "latent or early labor," "birth," "support," "nursing support," "obstetrics," and "onset of labor." Peer-reviewed research and quality improvement articles from 2009 to present were included if they had specific implications for nursing care during the latent phase of labor. Articles were excluded if they were not specific to nursing, focused exclusively on tool development, or were from the perspective of pregnant women or providers only.

RESULTS

Ten articles were included. Results were synthesized into six categories; support of physiologic labor and birth, the nurse's own personal view of labor, birth environment, techniques and tools, decision-making, and importance of latent labor discussion during the prenatal period.

CLINICAL IMPLICATIONS

Support for physiologic labor and birth is an important consideration for use of nonpharmacological methods during latent labor. The nurse's own personal view on labor support can influence the support that laboring women receive. Nurses may need additional education on labor support methods.

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.

Defining arrest in the first and second stages of labor

Normal labor is identified as regular uterine contractions in addition to dilation and effacement of the cervix. It is necessary to define normal labor in order to delineate when a woman's labor pattern diverges from that observed in most women. Labor irregularities are subdivided into protraction disorders and arrest disorders. Identifying abnormal labor patterns and initiating appropriate interventions is essential because prolonged labor is associated with an increase in perinatal morbidity. The aim of this review was to delineate both normal labor progress and also discuss the current evidence-based diagnosis and treatment of protraction and arrest disorders. Many subtleties go into defining the boundaries of the first and second stages of labor. Historically, the Friedman curve established normal limits; but currently Zhang has advanced these definitions by accounting for current demographical characteristics and practice environments. The most significant variables for defining normal progress of labor are parity and regional anesthesia status. The most common causes of labor abnormalities are uterine inactivity, obesity, cephalopelvic disproportion and fetal malposition. Risks of extending the first and/or second stage of labor include postpartum hemorrhage, intraamniotic infection and potentially an increase in neonatal adverse outcomes. The management of labor disorders consists of oxytocin administration, amniotomy, intrauterine pressure catheter use and shared decision-making regarding proceeding with expectant management, operative vaginal delivery or cesarean delivery after weighing the risks and benefits of each option. The decision to extend the duration of labor is personalized for each mother-baby dyad and should be agreed upon depending on individual maternal and fetal circumstances.

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.

Association of abnormal first stage of labor duration and maternal and neonatal morbidity

BACKGROUND

Contemporary guidelines for labor management do not characterize abnormal labor on the basis of maternal and/or neonatal morbidity.

OBJECTIVE

In this study, we aimed to evaluate the association of abnormal duration of the first stage of term labor and the risk of maternal and neonatal morbidity.

STUDY DESIGN

We conducted a retrospective analysis of prospectively collected data of all consecutive women admitted for delivery at a single center at ≥37 weeks and 0 to 7 days of gestation with singleton, nonanomalous, vertex infants from 2010 to 2015, who reached 10 cm cervical dilation. Multivariable logistic regression compared odds ratios for maternal and neonatal outcomes among women above and below the 90th, 95th, and 97th percentiles for first stage of labor duration. Receiver operating characteristic curves estimated the association between first stage of labor duration and maternal morbidity. Maternal morbidity was a composite of maternal fever, hemorrhage, transfusion, or endomyometritis; prolonged second stage of labor duration; and third- or fourth-degree perineal laceration. Neonatal morbidity was a composite of hypothermic therapy, need for mechanical ventilation, respiratory distress syndrome, meconium aspiration syndrome, birth injury or trauma, and neonatal seizure or sepsis.

RESULTS

Of 6823 women included in this study, 682 were anticipated to have first stage of labor duration above the 90th percentile cutoff point, which was associated with an increased risk of composite maternal morbidity, maternal fever, postpartum transfusion, prolonged second stage of labor duration, third- or fourth-degree perineal laceration, and cesarean or operative vaginal delivery (P≤.02) and an increased risk of composite neonatal morbidity, respiratory distress syndrome, need for mechanical ventilation, and neonatal sepsis (P≤.03). Composite maternal morbidity was 2.2 (95% confidence interval, 1.8-2.7), 1.9 (95% confidence interval, 1.4-2.4), and 1.8 (95% confidence interval, 1.3-2.5) times more likely to occur among women above the 90th, 95th, and 97th percentile, respectively, for first stage of labor duration from 4 to 10 cm. Composite neonatal morbidity was 2.6 (95% confidence interval, 2.1-3.2), 2.2 (95% confidence interval, 1.7-2.9), and 1.9 (95% confidence interval, 1.3-2.8) times more likely to occur among infants delivered by women above the 90th, 95th, and 97th percentiles for first stage of labor duration from 4 to 10 cm. Receiver operating characteristic curves among all women from 4 to 10 cm and 6 to 10 cm, including when stratified by parity and type of labor onset, had an area under the curve of 0.51 to 0.62 and 0.53 to 0.71 for maternal and neonatal morbidity, respectively. Thus, duration of labor has moderate predictive ability, at best, for composite maternal or neonatal morbidity. No curve demonstrated a clear point at which adverse maternal or neonatal outcomes increased that could be used to define abnormal labor.

CONCLUSION

The benefit of expectantly managing a prolonged first stage of labor with duration above the 90th percentile in anticipation of vaginal delivery must be weighed against the increased risk of composite maternal and neonatal morbidity. Risks associated with performing cesarean delivery as an alternative management for women with prolonged first stage of labor duration must also be considered.

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.

Induction of labor, and physiological and psychological stress responses as expressed by salivary cortisol: a prospective study

PURPOSE

To describe patterns of physiological and psychological stress during induced labor and their correlation to obstetrical and neonatal outcomes.

METHODS

This prospective, observational study included 167 women, with low-risk, singleton pregnancies, who delivered at term, at a tertiary academic center from 2015 through 2018. Among them, 72 (43%) underwent induction and 95 (57%) had spontaneous labor onset. Physiological stress was evaluated by salivary cortisol measurements and emotional stress by questionnaires (visual analogue stress scale 0-10) during latent phase, active phase and full dilation stages of labor, as well as 2 min and 2 h postpartum. Cord blood cortisol and pH were obtained. Stress patterns were compared between parturients who did or did not undergo induction. Modes of delivery, labor and delivery complications, and early neonatal outcomes were compared. Mothers completed the Hospital Anxiety and Depression Scale.

RESULTS

Induced women had lower cortisol concentrations during the latent phase compared to spontaneous onset of labor (p = 0.003), with no differences during active (p = 0.237), full dilation (0.668), 2 min and 2 h after delivery (p = 0.666). Stress scale and Hospital Anxiety and Depression Scale scores were similar between groups. Cord cortisol (p = 0.294), 1-min Apgar score ≤ 7 (p = 0.502) and 5-min Apgar score ≤ 7 (p = 0.37) were similar. All had cord pH > 7.

CONCLUSIONS

Induction does not increase stress during labor. Moreover, it might have a positive effect on reducing cortisol during the latent phase. These findings might reassure women who are concerned about induction of labor.

The Effect of Ultrasound-Measured Preinduction Cervical Length on Delivery Outcome in a Low-Resource Setting

Background

Induction of labour is not without risk, and it calls for a method that will be sensitive enough to predict successful labour induction.

Aim

This study aims to evaluate the role of transvaginal ultrasonographic cervical length measurement at term in the prediction of successful induction of labour (IOL).

Materials and Methods

This prospective study was carried out in the Department of Obstetrics and Gynaecology of Federal Teaching Hospital Abakaliki between 1st of July and 30^th of November 2015. Preinduction Bishop score and cervical length were assessed before induction of labour. Intracervical, cervical, extraamniotic Foley catheter was used to improve the Bishop score. The data were analyzed using the IBM SPSS Statistics 20.

Results

The mean maternal age of the study group was 30.68 ± 6.38 years with a range of 19–43 years. The mean gestational age and parity were 39.57 ± 1.49 and 1.85 ± 0.63, respectively. All the women studied had successful induction of labour with mean induction delivery time of 8.1 ± 3.0 hours and mean duration of labour of 7.4 ± 2.9 hours. Preinduction cervical length is a good predictor of a short duration of labour (P = 0.001). Parturient with a preinduction cervical length of less than 3 cm was likely to have labour lasting less than 6 hours (RR = 4.20 (95% CI 1.85–9.529).

Conclusion

Transvaginal sonographic measurement of cervical length provides a useful prediction of the likelihood of duration of labour following the induction of labour. It is recommended that IOL should be considered and success anticipated in a parturient with a cervical length less than 3 cm.

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.

Labor Curve Analysis of Medically Indicated Early Preterm Induction of Labor

OBJECTIVE

To analyze the labor curves of nulliparous and multiparous women between 23.0 and 34.0 weeks of gestation who underwent induction of labor and achieved vaginal delivery.

METHODS

This is a retrospective cohort study of all live singletons delivered vaginally after medically indicated induction of labor between 23.0 and 34.0 weeks of gestation from 2011 through 2014 at our institution. We excluded those with one or no cervical examinations available during labor. Prior cesarean delivery, 5-minute Apgar score less than 5, and arterial cord pH less than 7.0 were exclusions. The course of cervical dilation was modeled using repeated measures analysis, and smoothed curves for nulliparous and parous women were generated separately. Estimates of the median (5th-95th percentile) traverse times between two dilations were computed using interval censored regression. Traverse times (ie, the elapsed time between two given dilation measures) were compared between nulliparous and parous women.

RESULTS

Sixty-seven nulliparous and 69 multiparous women were included. Each group exhibited similar rates of change from 1 to 3 cm of dilation (median 3.6 hours nulliparous and 3.4 hours multiparous, P=.90). Nulliparous women progressed from 3 to 6 cm more slowly than multiparous women (median 10 hours vs 4.4 hours, P<.001). After 6 cm, both groups rapidly progressed to 10 cm (median 0.3 hours vs 0.3 hours, P=.64). Although the 95th percentile traverse time from 6 to 10 cm was about 2 hours in each group, progression from 1 to 6 cm at the 95th percentile was much longer (64.0 vs 42.2 hours).

CONCLUSION

Early preterm labor induction takes less time in multiparous women owing to more rapid progression from 3 to 6 cm. At the 95th percentile, both nulliparous and multiparous women delivered vaginally, even with latent labor lasting well longer than 24 hours.

Is Zhang the new Friedman: How should we evaluate the first stage of labor?

Norms used to describe and evaluate the first stage of labor have been historically based upon data from the middle of the twentieth century. More recent data has characterized the normal first stage of labor differently including that the latent phase of labor is longer not transitioning from latent to active labor until about 6 cm of cervical dilation in a majority of women, regardless of parity or whether labor was spontaneous or induced. Additionally, the amount of time that can take for progress to be made in active labor be longer than previously understood. These two factors would lead to a change in management with the diagnosis of arrest of the first stage of labor being made at 6 cm cervical dilation or beyond in the setting of ruptured membranes and no cervical change for at least 4 h of adequate contractions or 6 h of inadequate contractions.

Potential Impact of Guidelines for the Prevention of Cesarean Deliveries in a Contemporary Canadian Population

OBJECTIVE

This study sought to describe how the implementation of recent labour guidelines may affect the cesarean delivery rate in a population in Alberta.

METHODS

This retrospective study was conducted on primiparous women who were in labour with singleton term fetuses with cephalic presentation in Alberta from 2007 to 2016 (n = 181 738), and it used data from a perinatal database. Modelled cesarean delivery rates were calculated to determine the potential impact of the recent guidelines on the cesarean delivery rate by using the percentage of cesarean deliveries that occurred outside the threshold of the recent labour guidelines.

RESULTS

A total of 21.7% of the cesarean deliveries for dystocia occurred outside of the guidelines related to the first stage of labour arrest for spontaneous labour (n = 9282), and 45.4% occurred outside of the guidelines related to the first stage of labour arrest for induced labours (n = 11 712). A total of 69.0% of the cesarean deliveries for dystocia occurred outside of the failed induction of labour guidelines (n = 4921), and 55.4% occurred outside of the second stage labour arrest guidelines (n = 6632). Assuming that the labour arrest guidelines are effective at reducing the cesarean delivery rate 25% of the time, the cesarean delivery rate for primiparous women in labour would be reduced from 22.5% to 20.7%. Assuming a 75% adherence/effectiveness rate, the cesarean delivery rate would be reduced to 17.1%.

CONCLUSION

The recent labour guidelines have the potential to have a substantial impact on the intrapartum cesarean delivery rate in primiparous women with singleton fetuses with cephalic presentation at term if the guidelines are put into practice.

Metabolomic Pathways Predicting Labor Dystocia by Maternal Body Mass Index

Objectives  The purpose of this study was to evaluate the metabolic pathways activated in the serum of African-American women during late pregnancy that predicted term labor dystocia. Study Design  Matched case-control study ( n  = 97; 48 cases of term labor dystocia and 49 normal labor progression controls) with selection based on body mass index (BMI) at hospital admission and maternal age. Late pregnancy serum samples were analyzed using ultra-high-resolution metabolomics. Differentially expressed metabolic features and pathways between cases experiencing term labor dystocia and normal labor controls were evaluated in the total sample, among women who were obese at the time of labor (BMI ≥ 30 kg/m2), and among women who were not obese. Results  Labor dystocia was predicted by different metabolic pathways in late pregnancy serum among obese (androgen/estrogen biosynthesis) versus nonobese African-American women (fatty acid activation, steroid hormone biosynthesis, bile acid biosynthesis, glycosphingolipid metabolism). After adjusting for maternal BMI and age in the total sample, labor dystocia was predicted by tryptophan metabolic pathways in addition to C21 steroid hormone, glycosphingolipid, and androgen/estrogen metabolism. Conclusion  Metabolic pathways consistent with lipotoxicity, steroid hormone production, and tryptophan metabolism in late pregnancy serum were significantly associated with term labor dystocia in African-American women.

First stage of labor progression in women with large-for-gestational age infants

BACKGROUND

Women with suspected large-for-gestational age fetuses have higher rates of dysfunctional labor and labor arrest diagnoses and, consequently, higher rates of cesarean deliveries. The identification of the factors that significantly affect labor progression of women with large-for-gestational age infants may better inform expected duration of labor for certain subgroups of this population.

OBJECTIVE

Because the standards for the first stage of labor when large-for-gestational age is present have not been defined clearly, the present study aims to evaluate labor progress of women with large-for-gestational age infants who complete the first stage of labor after 3-cm cervical dilation.

STUDY DESIGN

We conducted a retrospective cohort study of patients who were admitted for labor from 2004-2014 with a term vertex singleton who achieved 10-cm cervical dilation. Labor curves were constructed with repeated measures regression and were compared between patients who delivered large-for-gestational age infants (actual birthweight, >90th percentile for gestational age) and those who delivered appropriate-for-gestational age infants (actual birthweight, 10-90th percentile for gestational age). Interval-censored regression estimated median duration of labor after 3-cm cervical dilation stratified by actual infant birthweight and further stratified by parity (nulliparity vs multiparity), labor onset (spontaneous [augmented and not augmented] and induced labor), pregestational diabetes mellitus or gestational diabetes mellitus status, and maternal body mass index (obese, ≥30 kg/m² vs not obese, <30 kg/m²). Multivariate analysis adjusted for confounding factors that were identified by bivariate analysis.

RESULTS

Among all 17,097 women who were included, 15,843 women (92.7%) had appropriate-for-gestational age infants; 1254 women (7.3%) had large-for-gestational age infants, of whom 387 (30.9%) were nulliparous; 464 women (37.0%) underwent induction of labor; 863 women (68.8%) were obese, and 158 women (12.6%) had diabetes mellitus or gestational diabetes mellitus. Women with large-for-gestational age infants had a slower progression from 3- to 10-cm cervical dilation compared with those with appropriate-for-gestational age infants (median, 8.57 hours [5th, 95th percentile, 2.95, 24.86] vs 6.46 hours [5th, 95th percentile, 2.23, 18.74]; P<.01). In the large-for-gestational age group, dilation from 6-10 cm progressed slower in nulliparous compared with multiparous women (3.28 hours [5th, 95th percentile, 0.71, 15.16] vs 2.03 hours [5th, 95th percentile, 0.44, 9.39]; P<.01) and in obese compared with not obese women (2.36 hours [5th, 95th percentile, 0.51, 10.91] vs 1.79 hours [5th, 95th percentile, 0.39, 8.31]; P<.01). Labor curves did not differ between large-for-gestational age and appropriate-for-gestational age groups when stratified by labor onset (nonaugmented spontaneous labor vs induced labor) or the presence of diabetes mellitus or gestational diabetes mellitus.

CONCLUSION

After 3-cm cervical dilation, the time required to reach the second stage of labor is greater in women with large-for-gestational age infants compared with those with appropriate-for-gestational age infants; these differences are most pronounced in nulliparous and obese women with large-for-gestational age infants in the active phase of labor (6-10 cm). Among women with large-for-gestational age infants, labor onset and presence of diabetes mellitus or gestational diabetes mellitus have no apparent effect on the duration of the first stage of labor after 3-cm cervical dilation.

INADEQUATE ADHERENCE TO THE RECOMMENDATIONS REGARDING LABOR INDUCTION AS A TRIGGER OF CESAREAN SECTION IN WOMEN WITH SINGLE, TERM PREGNANCY. A DESCRIPTIVE STUDY

OBJECTIVE

To describe the characteristics of the labor induction process associated with the excess number of cesarean sections in women subjected to this intervention.

METHODS

Descriptive historical. cohort that included pregnant women without a history of previous cesarean section, with single term pregnancy and cephalic presentation who were subjected to labor induction in a Level III com- plexity hospital in Medellín, Colombia, during the time period between May 2015 and October 2016. Consecutive sampling was used. Measured variables were maternal age, parity, gestational age, indica- tion for labor induction, cervical favorability, time of induction, quality of uterine activity achieved, type of delivery, and time point during induction when the decision of cesarean section was made. The clinical practice guidelines of international organizations of the specialty and the new guides arising from the 2012 proposal of limiting the first cesarean section were used in order to define ad- herence to the recommendations for induction.

RESULTS

Of the 2402 births, 289 which met the inclusion criteria were selected. Cesarean section was performed in 48% of the women subjected to induction, 60.8% nulliparous and 32.1% multiparous. Of those with unfavorable cervix, 72.2% received oxytocin for cervical maturation. Of the women subjected to delivery induction, 108 (37%) underwent cesarean section due to a diagnosis of failed induction. This was considered inadequate in all of them, considering that the diagnosis was made before reaching a dilatation of 6 cm in 88 (81.5%), with intact membranes in 67 (62%), with no uterine activity in 42 (38.9%), with poor quality uterine activity in 23 (21.3%) and in 55 (61%) who did not have at least 24 hours of latent phase before undergoing cesarean section.

CONCLUSIONS

Failure to adhere to the recommendations for adequate induction was found, added to a mistaken diagnosis of failed induction.

Identifying strategies to reduce cesarean section rates by using Robson ten-group classification

OBJECTIVE

To assess the cesarean section (CS) rates using Robson ten-group classification system (RTGCS) and the interventions combined with RTGCS which may reduce the CS rates.

METHODS

A total of 100,326 deliveries at Zekai Tahir Burak Research and Training Hospital in Ankara, Turkey between 2012 and 2018 were included in this study. Interventions including free mobilization of pregnant women, CS decision with the signature of three obstetricians, re-evaluate the CS decision, strictly obeying the failed induction algorithm to reduce the CS rates were started to be applied in 2017. The CS rates between 2012 and 2017 and in 2017 were compared to evaluate the effects of the interventions on CS rate regarding the Robson groups.

RESULTS

The overall CS rates in between 2012 and 2017 significantly reduced from 37,703/84,279 (44.7%) to 6738/16,047 (42.0%) in 2017, p < .001. Cephalopelvic disproportion and suspected macrosomia rates reduced from 4992/37,703 (13.3%) to 683/6738 (10.0%), p < .001 and from 668/37,703 (1.8%) to 96/6738 (1.4%), p = .030, respectively.

CONCLUSIONS

To the best of our knowledge, this study is the first that gives the birth data from Turkey using RTGCS and showed that some interventions combined with RTGCS to reduce CS rates should be properly used.

A Mathematical Model Relating Pitocin Use during Labor with Offspring Autism Development in terms of Oxytocin Receptor Desensitization in the Fetal Brain

This paper develops a mathematical model describing the potential buildup of high oxytocin concentrations in the maternal circulation during labor in terms of continuous Pitocin infusion rate, half-life, and maternal weight. Oxytocin override of the degradation of oxytocin by placental oxytocinase is introduced to model the potential transfer of oxytocin from the maternal circulation across the placenta into the fetal circulation and from there into the brain of the fetus. The desensitization unit D equal to 1.8E6 (pg·min)/ml is employed to establish a desensitization threshold and by extension, a downregulation threshold as a function of oxytocin override concentration and continuous Pitocin infusion time, that could be a factor in the subsequent development of autism among offspring. Epidemiological studies by Duke University [1], Yale University [2], and Harvard University [3] are discussed regarding Pitocin use and offspring autism development for an explanation of the weak correlations they identified. The findings of the Harvard epidemiological study are reinterpreted regarding Pitocin use and its conclusion questioned. Further evaluations of the findings of these three epidemiological studies are called for to incorporate medical information on quantity of Pitocin used, continuous Pitocin infusion rate, length of labor, and maternal weight to determine if a correlation can be established with offspring autism development above an empirically determined desensitization threshold for Pitocin use. Suggestions for research are discussed, including an alternative to continuous Pitocin infusion, pulsatile infusion of Pitocin during labor induction, which may mitigate possible offspring autism development.

The ARRIVE Trial: Interpretation from an Epidemiologic Perspective

The findings of the ARRIVE trial (A Randomized Trial of Induction Versus Expectant Management) were recently published. This multisite randomized trial was designed to provide evidence regarding whether labor induction or expectant management is associated with increased adverse perinatal outcomes and risk of cesarean birth among healthy nulliparous women at term. The trial reported that the primary outcome, a composite of adverse neonatal outcomes, was not significantly different between the 2 groups; the principal secondary outcome, cesarean birth, was significantly more common among women whose pregnancy was expectantly managed than among women whose labor was induced at 39 weeks. These results have the potential to change existing practice. Several aspects of the study design may influence its potential internal and external validity and should be considered in order to make sound causal inferences from this trial, which will in turn affect how its findings are translated to practice. Although chance and confounding are of minimal concern, given the sample size and randomization used in the study, selection bias may be a concern. Studies are vulnerable to selection bias when the sample population differs from eligible nonparticipants, including in randomized controlled trials. External validity is defined as the extent to which the study population and setting are representative of the larger source population the study intends to represent. External validity may be limited given the characteristics of the women enrolled in the ARRIVE trial and the practice settings where the study was conducted. This brief report provides concrete suggestions for further analyses that could help solidify conclusions from the trial, and for further research questions that will continue advancement toward answering this complex question of how best to manage labor and birth decisions at full term among low-risk women.

Balloon catheter for induction of labor in women with one previous cesarean and an unfavorable cervix

Introduction

When women with a previous cesarean section and an unfavorable cervix have an indication for delivery, the choice is to induce labor or to perform a cesarean section. This study aims to assess the effectiveness and safety of a balloon catheter as a method of induction of labor in women with one previous cesarean section and an unfavorable cervix compared with an elective repeat cesarean section.

Material and methods

We performed a prospective cohort study in 51 hospitals in the Netherlands on term women with one previous cesarean section, a live singleton fetus in cephalic position, an unfavorable cervix and an indication for delivery. We recorded obstetric, maternal and neonatal characteristics. We compared the outcome of women who were induced with a balloon catheter with the outcome of women who delivered by elective repeat cesarean section. Main outcomes were maternal and neonatal morbidity. Mode of delivery was a secondary outcome for women who were induced. Adjusted odds ratios (aOR) were calculated using logistic regression, adjusted for potential confounders.

Results

Analysis was performed on 993 women who were induced and 321 women who had a repeat cesarean section (August 2011 until September 2012). Among the women who were induced, 560 (56.4%) delivered vaginally and 11 (1.1%) sustained a uterine rupture. Composite adverse maternal outcome (uterine rupture, severe postpartum hemorrhage or postpartum infection) occurred in 73 (7.4%) in the balloon and 14 (4.5%) women in the repeat cesarean section group (aOR 1.58, 95% confidence interval [CI] 0.85‐2.96). Composite adverse neonatal outcome (Apgar score <7 at 5 minutes or umbilical pH <7.10) occurred in 57 (5.7%) and 10 (3.2%) neonates, respectively (aOR 1.40, 95% CI 0.87‐3.48). Women who were induced had a shorter postpartum admission time (2.0 vs 3.0 days (P < 0.0001)).

Conclusions

In women with a previous cesarean section and a need for delivery, induction of labor with a balloon catheter does not result in a significant increase in adverse maternal and neonatal outcomes as compared with planned cesarean section.

Influence of Maternal Obesity on Labor Induction: A Systematic Review and Meta-Analysis

INTRODUCTION

Studies have shown that women with obesity have longer labors. The purpose of this systematic review and meta-analysis is to examine existing evidence regarding labor induction in women with obesity, including processes and outcomes. The primary outcome was cesarean birth following labor induction. Secondary outcomes were the timing and dosage of prostaglandins, the success of mechanical cervical ripening methods, and synthetic oxytocin dose and timing.

METHODS

Searches were performed in PubMed, MEDLINE, Embase, CINAHL, EBSCO, the Cochrane Database of Systematic Reviews, the Database of Abstracts of Effects, Google Scholar, and ClinicalTrials.gov. Searches were limited to studies published in English after 1990. Ten studies published between 2009 and 2017 were included in this review. All were observational studies comparing processes and outcomes of induction of labor in relation to maternal body mass index. The primary outcome was cesarean birth following labor induction. We assessed heterogeneity using Cochran's Q test and tau-squared and I² statistics. We also calculated fixed-effect models to estimate pooled relative risks and weighted mean differences.

RESULTS

Ten cohort studies met inclusion criteria; 8 studies had data available for a meta-analysis of the primary outcome. Cesarean birth was more common among women with obesity compared with women of normal weight following labor induction (Mantel-Haenszel fixed-effect odds ratio, 1.82; 95% CI, 1.55-2.12; P < .001). Maternal obesity was associated with a longer time to birth, higher doses of prostaglandins, less frequent success of cervical ripening methods, and higher dose of synthetic oxytocin, as well as a longer time to birth after oxytocin use.

DISCUSSION

Women with obesity are more likely than women with a normal weight to end labor induction with cesarean birth. Additionally, women with obesity require longer labor inductions involving larger, more frequent applications of both cervical ripening methods and synthetic oxytocin.

Applying a physiologic partograph to Consortium on Safe Labor data to identify opportunities for safely decreasing cesarean births among nulliparous women

BACKGROUND

The timing of hospital admission for women with spontaneous labor onset and the criteria used to assess active labor progress and diagnose labor dystocia may significantly influence women's risk for primary cesarean birth. Our aims were to assess associations of labor status at admission (i.e., preactive or active) and active labor progress (i.e., dystocic or physiologic) with oxytocin augmentation, cesarean birth, and adverse neonatal outcome rates.

METHODS

A sample of low-risk, nulliparous women admitted to hospitals for spontaneous labor onset was extracted from the Consortium on Safe Labor (n = 27 077). Binomial logistic regression was used to assess associations between labor classifications and outcomes.

RESULTS

At admission, 68.0% of women were in preactive labor and 32.0% were in active labor. Cesarean rates for these groups were 18.0% and 7.2%, respectively (adjusted odds ratio [AOR] 2.69; 95% CI 2.45-2.96). Oxytocin augmentation and adverse neonatal outcomes were more likely for women admitted in preactive labor. Among women admitted in active labor, 9.3% experienced labor dystocia and 90.7% progressed physiologically. Cesarean rates for these groups were 20.4% and 5.9%, respectively (AOR 3.02; 95% CI 2.45-3.73). Nearly half of the cesareans performed for dystocia among women admitted in active labor occurred when cervical dilation was physiologic. Oxytocin augmentation and adverse neonatal outcomes were more likely when active labor was dystocic.

CONCLUSIONS

Adoption of evidence-based, standardized approaches for diagnosing active labor onset, assessing labor progress, and diagnosing dystocia may safely decrease oxytocin augmentation and cesarean birth rates in the United States.

The expected labor progression after labor augmentation with oxytocin: A retrospective cohort study

OBJECTIVE

To describe labor progression patterns with oxytocin for augmentation in women who achieve vaginal delivery; and to determine how long one should wait with effective uterine contraction before labor arrest can be diagnosed.

DESIGN

Population-based retrospective cohort study.

POPULATION

The final sample involved 8,988 women with singleton gestation, term live birth, vertex presentation, no previous cesarean section, vaginal delivery, and neonatal Apgar score at 5 minutes at 7 or higher, and complete information on oxytocin augmentation in 2005-2007.

METHODS

Linear interpolation was used from the vaginal exam records for each woman to estimate the cervical dilation when oxytocin was started and the highest dose was first reached by parity. We used survival methods to estimate quartiles of the traverse time distributions of cervical dilation.

MAIN OUTCOME MEASURES

Duration of labor under oxytocin augmentation.

RESULTS

When oxytocin was just started, it took a long time to observe cervical dilation. The 50th(95th) centiles of the time interval from 4 to 5 cm, 5 to 6 cm, and 6 to 10 cm dilation were 2.9(8.8) hr, 1.7(5.8) hr, and 2.1(6.0) hr in nulliparas; and 3.1(10.1) hr, 1.9(8.0) hr, and 1.7(6.2) hr in multiparas. After effective uterine contractions were achieved under oxytocin, labor progressed much faster. The corresponding values were 0.7(2.4)hr, 0.5(1.5)hr, and 0.5(1.5)hr in nulliparas; and 0.6(1.9)hr, 0.4(1.1)hr, and 0.4(0.9)hr in multiparas. Low- and high-dose oxytocin regimens had similar effects on labor.

CONCLUSION

When oxytocin is just started for labor augmentation in early first stage, it may take up to 10 hours for the cervix to dilate by 1 cm. Once effective uterine contractions are achieved and the cervix is dilated more than 5 cm, cervical dilation to the next centimeter occurs within 2 hrs in both nulliparas and multiparas in 95% of the cases. High- and low-dose oxytocin had a similar impact on labor progression in augmented labor.

Simulation model of the relationship between cesarean section rates and labor duration

Cesarean delivery is the most common major abdominal surgery in many parts of the world, and it accounts for nearly one-third of births in the United States. For a patient who requires a C-section, allowing prolonged labor is not recommended because of the increased risk of infection. However, for a patient who is capable of a successful vaginal delivery, performing an unnecessary C-section can have a substantial adverse impact on the patient's future health. We develop two stochastic simulation models of the delivery process for women in labor; and our objectives are (i) to represent the natural progression of labor and thereby gain insights concerning the duration of labor as it depends on the dilation state for induced, augmented, and spontaneous labors; and (ii) to evaluate the Friedman curve and other labor-progression rules, including their impact on the C-section rate and on the rates of maternal and fetal complications. To use a shifted lognormal distribution for modeling the duration of labor in each dilation state and for each type of labor, we formulate a percentile-matching procedure that requires three estimated quantiles of each distribution as reported in the literature. Based on results generated by both simulation models, we concluded that for singleton births by nulliparous women with no prior complications, labor duration longer than two hours (i.e., the time limit for labor arrest based on the Friedman curve) should be allowed in each dilation state; furthermore, the allowed labor duration should be a function of dilation state.

In vivo Raman spectroscopy for biochemical monitoring of the human cervix throughout pregnancy

BACKGROUND

The cervix must undergo significant biochemical remodeling to allow for successful parturition. This process is not fully understood, especially in instances of spontaneous preterm birth. In vivo Raman spectroscopy is an optical technique that can be used to investigate the biochemical composition of tissue longitudinally and noninvasively in human beings, and has been utilized to measure physiology and disease states in a variety of medical applications.

OBJECTIVE

The purpose of this study is to measure in vivo Raman spectra of the cervix throughout pregnancy in women, and to identify biochemical markers that change with the preparation for delivery and postpartum repair.

STUDY DESIGN

In all, 68 healthy pregnant women were recruited. Raman spectra were measured from the cervix of each patient monthly in the first and second trimesters, weekly in the third trimester, and at the 6-week postpartum visit. Raman spectra were measured using an in vivo Raman system with an optical fiber probe to excite the tissue with 785 nm light. A spectral model was developed to highlight spectral regions that undergo the most changes throughout pregnancy, which were subsequently used for identifying Raman peaks for further analysis. These peaks were analyzed longitudinally to determine if they underwent significant changes over the course of pregnancy (P < .05). Finally, 6 individual components that comprise key biochemical constituents of the human cervix were measured to extract their contributions in spectral changes throughout pregnancy using a linear combination method. Patient factors including body mass index and parity were included as variables in these analyses.

RESULTS

Raman peaks indicative of extracellular matrix proteins (1248 and 1254 cm^-1) significantly decreased (P < .05), while peaks corresponding to blood (1233 and 1563 cm^-1) significantly increased (P < .0005) in a linear manner throughout pregnancy. In the postpartum cervix, significant increases in peaks corresponding to actin (1003, 1339, and 1657 cm^-1) and cholesterol (1447 cm^-1) were observed when compared to late gestation, while signatures from blood significantly decreased. Postpartum actin signals were significantly higher than early pregnancy, whereas extracellular matrix proteins and water signals were significantly lower than early weeks of gestation. Parity had a significant effect on blood and extracellular matrix protein signals, with nulliparous patients having significant increases in blood signals throughout pregnancy, and higher extracellular matrix protein signals in early pregnancy compared to patients with prior pregnancies. Body mass index significantly affected actin signal contribution, with low body mass index patients showing decreasing actin contribution throughout pregnancy and high body mass index patients demonstrating increasing actin signals.

CONCLUSION

Raman spectroscopy was successfully used to biochemically monitor cervical remodeling in pregnant women during prenatal visits. This foundational study has demonstrated sensitivity to known biochemical dynamics that occur during cervical remodeling, and identified patient variables that have significant effects on Raman spectra throughout pregnancy. Raman spectroscopy has the potential to improve our understanding of cervical maturation, and be used as a noninvasive preterm birth risk assessment tool to reduce the incidence, morbidity, and mortality caused by preterm birth.

Progression of the first stage of spontaneous labour: A prospective cohort study in two sub-Saharan African countries

BACKGROUND

Escalation in the global rates of labour interventions, particularly cesarean section and oxytocin augmentation, has renewed interest in a better understanding of natural labour progression. Methodological advancements in statistical and computational techniques addressing the limitations of pioneer studies have led to novel findings and triggered a re-evaluation of current labour practices. As part of the World Health Organization's Better Outcomes in Labour Difficulty (BOLD) project, which aimed to develop a new labour monitoring-to-action tool, we examined the patterns of labour progression as depicted by cervical dilatation over time in a cohort of women in Nigeria and Uganda who gave birth vaginally following a spontaneous labour onset.

METHODS AND FINDINGS

This was a prospective, multicentre, cohort study of 5,606 women with singleton, vertex, term gestation who presented at ≤ 6 cm of cervical dilatation following a spontaneous labour onset that resulted in a vaginal birth with no adverse birth outcomes in 13 hospitals across Nigeria and Uganda. We independently applied survival analysis and multistate Markov models to estimate the duration of labour centimetre by centimetre until 10 cm and the cumulative duration of labour from the cervical dilatation at admission through 10 cm. Multistate Markov and nonlinear mixed models were separately used to construct average labour curves. All analyses were conducted according to three parity groups: parity = 0 (n = 2,166), parity = 1 (n = 1,488), and parity = 2+ (n = 1,952). We performed sensitivity analyses to assess the impact of oxytocin augmentation on labour progression by re-examining the progression patterns after excluding women with augmented labours. Labour was augmented with oxytocin in 40% of nulliparous and 28% of multiparous women. The median time to advance by 1 cm exceeded 1 hour until 5 cm was reached in both nulliparous and multiparous women. Based on a 95th percentile threshold, nulliparous women may take up to 7 hours to progress from 4 to 5 cm and over 3 hours to progress from 5 to 6 cm. Median cumulative duration of labour indicates that nulliparous women admitted at 4 cm, 5 cm, and 6 cm reached 10 cm within an expected time frame if the dilatation rate was ≥ 1 cm/hour, but their corresponding 95th percentiles show that labour could last up to 14, 11, and 9 hours, respectively. Substantial differences exist between actual plots of labour progression of individual women and the 'average labour curves' derived from study population-level data. Exclusion of women with augmented labours from the study population resulted in slightly faster labour progression patterns.

CONCLUSIONS

Cervical dilatation during labour in the slowest-yet-normal women can progress more slowly than the widely accepted benchmark of 1 cm/hour, irrespective of parity. Interventions to expedite labour to conform to a cervical dilatation threshold of 1 cm/hour may be inappropriate, especially when applied before 5 cm in nulliparous and multiparous women. Averaged labour curves may not truly reflect the variability associated with labour progression, and their use for decision-making in labour management should be de-emphasized.

A randomized, double-blinded, controlled trial of the effects of fluid rate and/or presence of dextrose in intravenous fluids on the labor course of nulliparas

BACKGROUND

Prolonged labor has been demonstrated to increase adverse maternal and neonatal outcome. A practice that may decrease the risk of prolonged labor is the modification of fluid intake during labor.

OBJECTIVE

Several studies demonstrated that increased hydration in labor as well as addition of dextrose-containing fluids may be associated with a decrease in length of labor. The purpose of our study was to characterize whether high-dose intravenous fluids, standard-dose fluids with dextrose, or high-dose fluids with dextrose show a difference in the duration of labor in nulliparas.

STUDY DESIGN

Nulliparous subjects with singletons who presented in active labor were randomized to 1 of 3 groups of intravenous fluids: 250 mL/h of normal saline, 125 mL/h of 5% dextrose in normal saline, or 250 mL/h of 2.5% dextrose in normal saline. The primary outcome was total length of labor from initiation of intravenous fluid in vaginally delivered subjects. Secondary outcomes included cesarean delivery rate and length of second stage of labor, among other maternal and neonatal outcomes.

RESULTS

In all, 274 subjects who met inclusion criteria were enrolled. There were no differences in baseline characteristics among the 3 groups. There was no difference in the primary outcome of total length of labor in vaginally delivered subjects among the 3 groups. First stage of labor duration, second stage of labor duration, and cesarean delivery rates were also equivalent. There were no differences identified in other secondary outcomes including clinical chorioamnionitis, postpartum hemorrhage, blood loss, Apgar scores, or neonatal intensive care admission.

CONCLUSION

There is no difference in length of labor or delivery outcomes when comparing high-dose intravenous fluids, addition of dextrose, or use of high-dose intravenous fluids with dextrose in nulliparous women who present in active labor.

Duration of labor and the risk of severe postpartum hemorrhage: A case-control study

Objective

Our main objective was to investigate the association between duration of active labor and severe postpartum hemorrhage. We examined the effect of the total duration of active labor, the effect of each stage of active labor, and the gradient effect of duration of labor on severe postpartum hemorrhage.

Methods

A case-control study was generated from a source population of all women admitted for delivery at Oslo University Hospital and Drammen Hospital in Buskerud municipality during the time period January 1, 2008 to December 31, 2011. The study population included all cases of severe postpartum hemorrhage (n = 859) and a random sample of controls (n = 1755). Severe postpartum hemorrhage was defined as postpartum blood loss ≥1500 mL or need for blood transfusion. Prolonged labor was defined as duration of active labor >12 hours according to the definition of the World Health Organization. We used logistic multivariable regression in the analysis.

Results

We observed a significantly longer mean duration of labor in women who experienced severe postpartum hemorrhage compared to controls (5.4 versus 3.8 hours, p<0.001). Women with severe postpartum hemorrhage also had a longer duration of all stages of active labor compared to controls. The association between the duration of active labor and severe postpartum changed from a linear dose-response association to a threshold association after adjusting for augmentation with oxytocin, induction of labor, primiparity, and fever during labor. Compared to controls, women with severe postpartum hemorrhage were more likely to have a prolonged labor >12 hours (adjusted odds ratio = 2.44, 95% confidence interval: 1.69–3.53, p< 0.001).

Conclusion

Prolonged active labor (duration >12 hours) was associated with severe postpartum hemorrhage. Increased vigilance seems required when the labor is prolonged to reduce the risk of severe postpartum hemorrhage.

Worth the Wait? The Effect of Early Term Birth on Maternal and Infant Health

Early term birth is defined as birth at 37 or 38 weeks gestation. While infants born early term are not considered premature, the medical literature suggests that they have an increased risk of serious adverse health outcomes compared to infants born at term (39 or 40 weeks). Despite these known harms, we document a rise in early term births in the United States from 1989 to the mid-2000s, followed by a decline in recent years. We posit that the recent decline in early term births has been driven by changes in medical practice advocated by the American College of Obstetricians and Gynecologists, programs such as the March of Dimes’ "Worth the Wait" campaign, and by Medicaid policy. We first show that this pattern cannot be attributed to changes in the demographic composition of mothers, and provide some evidence that efforts to reduce early term elective deliveries (EEDs) through Medicaid policy were effective. We next exploit county-level variation in the timing of these changes in medical practice to examine the effect of early term inductions (our proxy for EEDs) on infant and maternal health. We find that early term inductions lower birth weights and increase the risks of precipitous labor, birth injury, and required ventilation. Our results suggest that reductions in early term inductions can explain about one-third of the overall increase in birth weights between 2010 and 2013 for births at 37 weeks gestation and above.