Defining an abnormal first stage of labor based on maternal and neonatal outcomes

Inconsistent definitions of prolonged labor in international literature: a scoping review

Objective

Prolonged labor is the commonest indication for intrapartum cesarean section, but definitions are inconsistent and some common definitions were recently found to overestimate the speed of physiological labor. The objective of this review is to establish an overview of synonyms and definitions used in the literature for prolonged labor, separated into first and second stages, and establish types of definitions used.

Data sources

A systematic search was conducted in PubMed, Embase, Web of Science, Cochrane Library, Emcare, and Academic Search Premier.

Study eligibility criteria

All articles in English that (1) attempted to define prolonged labor, (2) included a definition of prolonged labor, or (3) included any synonym for prolonged labor, were included.

Methods

Data on study design, year of publication, country or region of origin, synonyms used, definition of prolonged first and/or second stage, and origin of provided definition (if not primarily established by the study) were collected into a database.

Results

In total, 3402 abstracts and 536 full-text papers were screened, and 232 papers were included. Our search established 53 synonyms for prolonged labor. Forty-three studies defined prolonged labor and 189 studies adopted a definition of prolonged labor. Definitions for prolonged first stage of labor were categorized into: time-based (n=14), progress-based (n=12), clinician-based (n=5), or outcome-based (n=4). For the 33 studies defining prolonged second stage, the majority of definitions (n=25) were time-based, either based on total duration or duration of no descent of the presenting part.

Conclusions

Despite efforts to arrive at uniform labor curves, there is still little uniformity in definitions of prolonged labor. Consensus on which definition to use is called for, in order to safely and respectfully allow physiological labor progress, ensure timely management, and assess and compare incidence of prolonged labor between settings.

Duration of the active first stage of labour and severe perineal lacerations and maternal postpartum complications: a population-based cohort study

OBJECTIVE

The impact of first stage labour duration on maternal outcomes is sparsely investigated. We aimed to study the association between a longer active first stage and maternal complications in the early postpartum period.

DESIGN

A population-based cohort study.

SETTING

Regions of Stockholm and Gotland, Sweden, 2008-2020.

POPULATION

A cohort of 159 459 term, singleton, vertex pregnancies, stratified by parity groups.

METHODS

The exposure was active first stage duration, categorised in percentiles. Poisson regression analysis was performed to estimate the adjusted relative risk (aRR) and the 95% confidence interval (95% CI). To investigate the effect of second stage duration on the outcome, mediation analysis was performed.

MAIN OUTCOME MEASURES

Severe perineal lacerations (third or fourth degree), postpartum infection, urinary retention and haematoma in the birth canal or ruptured sutures.

RESULTS

The risks of severe perineal laceration, postpartum infection and urinary retention increased with a longer active first stage, both overall and stratified by parity group. The aRR increased with a longer active first stage, using duration of <50th percentile as the reference. In the ≥90th percentile category, the aRR for postpartum infection was 1.64 (95% CI 1.46-1.84) in primiparous women, 2.43 (95% CI 1.98-2.98) in parous women with no previous caesarean delivery (CD) and 2.33 (95% CI 1.65-3.28) in parous women with a previous CD. The proportion mediated by second stage duration was 33.4% to 36.9% for the different outcomes in primiparous women. The risk of haematoma or ruptured sutures did not increased with a longer active first stage.

CONCLUSIONS

Increasing active first stage duration is associated with maternal complications in the early postpartum period.

The effect of intravenous hyoscine butylbromide on slow progress in labor (BUSCLAB): A double-blind randomized placebo-controlled trial

BACKGROUND

Prolonged labor is a common condition associated with maternal and perinatal complications. The standard treatment with oxytocin for augmentation of labor increases the risk of adverse outcomes. Hyoscine butylbromide is a spasmolytic drug with few side effects shown to shorten labor when used in a general population of laboring women. However, research on its effect on preventing prolonged labor is lacking. We aimed to assess the effect of hyoscine butylbromide on the duration of labor in nulliparous women showing early signs of slow labor.

METHODS AND FINDINGS

In this double-blind randomized placebo-controlled trial, we included 249 nulliparous women at term with 1 fetus in cephalic presentation and spontaneous start of labor, showing early signs of prolonged labor by crossing the alert line of the World Health Organization (WHO) partograph. The trial was conducted at Oslo University Hospital in Norway from May 2019 to December 2021. One hundred and twenty-five participants were randomized to receive 1 ml hyoscine butylbromide (Buscopan) (20 mg/ml), while 124 received 1 ml sodium chloride intravenously. Randomization was computer-generated, with allocation concealment by opaque sequentially numbered sealed envelopes. The primary outcome was duration of labor from administration of the investigational medicinal product (IMP) to vaginal delivery, which was analyzed by Weibull regression to estimate the cause-specific hazard ratio (HR) of vaginal delivery between the 2 treatment groups, with associated 95% confidence interval (CI). A wide range of secondary maternal and perinatal outcomes were also evaluated. Time-to-event outcomes were analyzed by Weibull regression, whereas continuous and dichotomous outcomes were analyzed by median regression and logistic regression, respectively. All main analyses were based on the modified intention-to-treat (ITT) set of eligible women with signed informed consent receiving either of the 2 treatments. The follow-up period lasted during the postpartum hospital stay. All personnel, participants, and researchers were blinded to the treatment allocation. Median (mean) labor duration from IMP administration to vaginal delivery was 401 (440.8) min in the hyoscine butylbromide group versus 432.5 (453.6) min in the placebo group. We found no statistically significant association between IMP and duration of labor from IMP administration to vaginal delivery: cause-specific HR of 1.00 (95% CI [0.77, 1.29]; p = 0.993). Among 255 randomized women having received 1 dose of IMP, 169 women (66.3%) reported a mild adverse event: 75.2% in the hyoscine butylbromide group and 57.1% in the placebo group (Pearson's chi-square test: p = 0.002). More than half of eligible women were not included in the study because they did not wish to participate or were not included upon admission. The participants might have represented a selected group of women reducing the external validity of the study.

CONCLUSIONS

One intravenous dose of 20 mg hyoscine butylbromide was not found to be superior to placebo in preventing slow labor progress in a population of first-time mothers at risk of prolonged labor. Further research is warranted to answer whether increased and/or repeated doses of hyoscine butylbromide might have an effect on duration of labor.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT03961165) EudraCT (2018-002338-19).

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.

Prolonged labor and adverse cardiac outcomes in pregnant patients with congenital heart disease

BACKGROUND

Patients with congenital heart disease are at high risk for peripartum cardiac morbidity, yet data on the impact of duration of labor on cardiac outcomes are limited. Prolonged labor is a known risk factor for maternal morbidity, but the impact of prolonged labor on cardiac outcomes in patients with congenital heart disease has not been evaluated.

OBJECTIVE

This study aimed to evaluate the association between prolonged labor (≥24 hours) and adverse peripartum maternal cardiac outcomes in pregnant patients with congenital heart disease.

STUDY DESIGN

This was a retrospective cohort study of pregnant patients ≥18 years with congenital heart disease who received prenatal care and delivered at an academic institution between 1998 and 2020 with a singleton gestation. Pregnancies that ended <20 weeks' gestation and patients who underwent an outright cesarean delivery without exposure to labor were excluded. The primary outcome was a composite adverse maternal cardiac outcome that occurred intrapartum or up to 6 weeks postpartum, defined as the occurrence of 1 or more of the following events: heart failure or clinical volume overload requiring diuresis, pulmonary edema, arrhythmia requiring treatment, thromboembolic complications including deep vein thrombosis or pulmonary embolism, transient ischemic attack, stroke, endocarditis, myocardial infarction, aortic dissection, cardiac arrest, or cardiac death. Outcomes were compared between patients with prolonged labor (≥24 hours) and those without prolonged labor (<24 hours). An interaction between prolonged labor and cesarean delivery was evaluated.

RESULTS

A total of 229 patients were included. The median duration of labor was 14 hours, and 18% of patients labored for ≥24 hours. Overall, 11.8% experienced the composite cardiac outcome with a significantly higher rate in the prolonged labor group (22% vs 9.6%; P=.03). After adjusting for confounders, including nulliparity, labor induction, gestational age, and World Health Organization class, there was a 2.7-fold increase in the odds of the composite cardiac outcome for patients who experienced prolonged labor (adjusted odds ratio, 2.7; 95% confidence interval, 1.1-7.1). There was no significant difference in cardiac outcome between those who had a vaginal delivery and those who had a cesarean delivery during labor (10.0% vs 16.1%; P=.18). There was, however, a significant interaction between prolonged labor and cesarean delivery; after adjustment for confounders, patients who underwent a cesarean delivery after prolonged labor had a 6.8-fold increase in the odds of experiencing the composite cardiac outcome when compared with those who underwent a cesarean delivery without prolonged labor (30.8% vs 7.1%; adjusted odds ratio, 6.8; 95% confidence interval, 1.4-32.5), most commonly, heart failure or volume overload requiring diuresis.

CONCLUSION

In a cohort of pregnant patients with congenital heart disease, prolonged duration of labor ≥24 hours was significantly associated with an increased risk for an adverse peripartum cardiac outcome, especially among those who underwent a cesarean delivery after that time. These findings suggest that close attention should be paid to the duration of labor, and those who require a cesarean delivery after a prolonged labor should be monitored closely for signs of volume overload and other adverse cardiac events.

New insights on labor progression: a systematic review

The past 20 years witnessed an invigoration of research on labor progression and a change of thinking regarding normal labor. New evidence is emerging, and more advanced statistical methods are applied to labor progression analyses. Given the wide variations in the onset of active labor and the pattern of labor progression, there is an emerging consensus that the definition of abnormal labor may not be related to an idealized or average labor curve. Alternative approaches to guide labor management have been proposed; for example, using an upper limit of a distribution of labor duration to define abnormally slow labor. Nonetheless, the methods of labor assessment are still primitive and subject to error; more objective measures and more advanced instruments are needed to identify the onset of active labor, monitor labor progression, and define when labor duration is associated with maternal/child risk. Cervical dilation alone may be insufficient to define active labor, and incorporating more physical and biochemical measures may improve accuracy of diagnosing active labor onset and progression. Because the association between duration of labor and perinatal outcomes is rather complex and influenced by various underlying and iatrogenic conditions, future research must carefully explore how to integrate statistical cut-points with clinical outcomes to reach a practical definition of labor abnormalities. Finally, research regarding the complex labor process may benefit from new approaches, such as machine learning technologies and artificial intelligence to improve the predictability of successful vaginal delivery with normal perinatal outcomes.

The evolution of the labor curve and its implications for clinical practice: the relationship between cervical dilation, station, and time during labor

The assessment of labor progress is germane to every woman in labor. Two labor disorders-arrest of dilation and arrest of descent-are the primary indications for surgery in close to 50% of all intrapartum cesarean deliveries and are often contributing indications for cesarean deliveries for fetal heart rate abnormalities. Beginning in 1954, the assessment of labor progress was transformed by Friedman. He published a series of seminal works describing the relationship between cervical dilation, station of the presenting part, and time. He proposed nomenclature for the classification of labor disorders. Generations of obstetricians used this terminology and normal labor curves to determine expected rates of dilation and fetal descent and to decide when intervention was required. The analysis of labor progress presents many mathematical challenges. Clinical measurements of dilation and station are imprecise and prone to variation, especially for inexperienced observers. Many interrelated factors influence how the cervix dilates and how the fetus descends. There is substantial variability in when data collection begins and in the frequency of examinations. Statistical methods to account for these issues have advanced considerably in recent decades. In parallel, there is growing recognition among clinicians of the limitations of using time alone to assess progress in cervical dilation in labor. There is wide variation in the patterns of dilation over time and most labors do not follow an average dilation curve. Reliable assessment of labor progression is important because uncertainty leads to both over-use and under-use of cesarean delivery and neither of these extremes are desirable. This review traces the evolution of labor curves, describes how limitations are being addressed to reduce uncertainty and to improve the assessment of labor progression using modern statistical techniques and multi-dimensional data, and discusses the implications for obstetrical practice.

Implementation of glucose 5% supplementation protocol to reduce the duration of labor among women with cervical ripening by prostaglandins: The GLUCOSHORT before-and-after study

INTRODUCTION

Previous publications have shown that glucose supplementation could reduce labor duration in women with induction of labor with a favorable cervix but none have shown it for women with an unfavorable cervix.  The purpose of our study was to assess the impact on labor duration of a protocol of glucose supplementation used for induction of labor in women with an unfavorable cervix.

MATERIAL AND METHODS

The protocol implemented in November 2017 added glucose supplementation by 5% dextrose at 125 mL/h to Ringer lactate for women with an unfavorable cervix with labor induced with dinoprostone gel. The study included women who underwent this protocol with a singleton, term, cephalic fetus from June 2017 through April 2018. The primary outcome was the labor duration. The secondary outcomes were mode of delivery, postpartum hemorrhage rate, neonatal outcomes, and durations other stage of labor. These outcomes were compared between the pre-intervention (from June 1 to October 31, 2017) and post-intervention (from December 1, 2017 to April 30, 2018) periods.

RESULTS

The pre-intervention period included 116 women, and the post-intervention period 123. The characteristics of women and the induction of labor were similar in the two periods. The median duration from induction to delivery was not significantly different between the two periods (13.2 h, IQR 9.1-18.6 versus 13.6 h IQR 9.3-18.3, P=.67). The secondary outcomes did not differ significantly between the two groups.

DISCUSSION

Glucose supplementation administered to women with an unfavorable cervix undergoing induction does not appear to reduce the induction-delivery duration.

The single pregnancy predicting model of 1 minute Apgar score less than 7 after preterm birth: A retrospective study

Preterm delivery is greatly associated with perinatal mortality and morbidity, while there is no objective way to identify high-risk newborns currently. This study aimed at discovering the risk factor for Apgar score less than 7 at 1 minute of preterm neonates born with vaginal delivery. A retrospective study was performed in single pregnancy women with a vaginal delivery before 37 weeks of gestation. All the preterm infants were categorized into three types: very preterm birth (28 to 32 weeks), moderate preterm birth (32 to 34 weeks) and late preterm birth (34 to 37 weeks). Risk factors were identified through logistic regression analysis in every category of newborns mentioned above. And the receiver operating characteristic analysis was used in continuous variables to determine the best threshold of the outcome. On the basis of the selected factors, the predicting models are created and its prognosticating ability is compared by the area under the curve. A nomogram was established for the proved best model. A total of 981 cases were investigated, of whom 55 were found with 1 min Apgar scores less than 7. The nomogram was set for the predicting model with larger area under the receiver operating characteristic curve, of which is 0.742(95% confidence interval = 0.670-0.805) in very preterm birth, with the variables of first and second labor stage(> = 1.6 hours), birthweight and MgSO4(magnesium sulfate), and is 0.807(95% confidence interval = 0.776-0.837) in late preterm birth, with the variables of second labor stage(> = 1.23 hours), birthweight, a history of previous cesarean delivery, fetal distress and placental abruption. The combination of first and second labor stage, newborn weight and MgSO4 use can predict 74.2% of 1 minute Apgar score < 7 in very preterm neonates. And 80.7% high-risk infants can be identified when second labor stage, newborn weight, VBAC (vaginal birth after cesarean) and the occur of placental abruption and fetal distress were combined in the predicting model for late preterm birth. These predicting models would bring out great assistance towards obstetricians and reduce unnecessary adverse fetal outcomes.

Assessing maternal thyroid function and its relationship to duration of the first stage of labor

INTRODUCTION

Maternal thyroid function plays a critical role in the normal labor process. Whether maternal thyroid function affects the duration of the first stage of labor is still unknown.

METHODS

Maternal serum levels of free thyroxine (FT4), thyroid-stimulating hormone (TSH) and thyroid peroxidase antibody (TPOAb) were detected in 31,382 pregnant women. A multiple linear regression model was applied to investigate the effect of maternal thyroid function on the duration of the first stage of labor.

RESULTS

FT4 level in the second trimester and in the third trimester was found to be negatively associated with duration of the first stage of labor (β = -1.30 h, 95% CI: -2.28, -0.32, P < 0.01; β = -0.35 h, 95% CI: -0.61, -0.10, P < 0.01). TSH level in the third trimester was found to be positively associated with the duration of the first stage of labor (β = 0.12 h, 95% CI: 0.06, 0.18, P < 0.001). Per unit increase in TPOAb (IU/mL) in the second trimester and in the third trimester was significantly associated with prolonged first stage of labor (β = 0.08 h, 95% CI: 0.01, 0.14, P = 0.02; β = 0.09 h, 95% CI: 0.02, 0.15, P = 0.01). For pregnant women suffering from subclinical hypothyroidism combined without TPOAb, TSH level in the third trimester exhibited a significant positive association with the length of the first stage of labor (β = 2.44 h, 95% CI: 0.03, 4.84, P = 0.04).

CONCLUSIONS

These findings suggest that maternal FT4, TSH and TPOAb might be important predictors of the first stage of labor.

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.

The value of intrapartum factors in predicting maternal morbidity

BACKGROUND

The rates of severe maternal morbidity and mortality in the United States exceed those in other high-income nations. To aid providers and hospitals in recognizing the risk factors, there have been multiple attempts to develop stratification systems for morbidity based on maternal comorbidities. However, most women giving birth are healthy and do not have comorbidities to suggest that they are at an increased risk for severe maternal morbidity. There are small but inherent maternal risks to labor, and the events after admission may further influence a woman's risk for morbidity even for those initially at a low risk.

OBJECTIVE

To determine if the incorporation of intrapartum factors known at the start of the second stage of labor improves the predictive performance of a comorbidity-based risk tool for severe maternal morbidity.

STUDY DESIGN

This is a retrospective cohort study of women at 8 hospitals in a single health system between July 1, 2016, and June 30, 2020. The women had term, singleton gestations and were admitted in labor and reached the second stage. The primary outcome was severe maternal morbidity. We compared logistic regression models using a validated risk-scoring tool (the Expanded Obstetric Comorbidity Score, which uses diagnosis codes for maternal comorbidities and pregnancy characteristics to predict maternal morbidity) with a model that included the Expanded Obstetric Comorbidity Score combined with parity and intrapartum factors. The intrapartum factors included labor induction or augmentation, length of labor, prolonged rupture of membranes, the presence of meconium-stained amniotic fluid, and gestational age. The hospitals were divided into a training (n=4) and testing (n=4) set to evaluate the predictive model performance. Discrimination was assessed by calculating the area under the receiver operating curve and calibration via calibration plots. Similar model comparisons were performed in a subgroup of women, who the Expanded Obstetric Comorbidity Score predicted to be at low risk for morbidity.

RESULTS

This analysis included 33,770 deliveries from the 8 hospitals; severe maternal morbidity occurred in 498 (1.5%) deliveries. The model performance is reported among the testing set (n=15,350). Using the Expanded Obstetric Comorbidity Score alone, the area under the receiver operating curve was 0.676 (95% confidence interval, 0.636-0.716) and 155 (71%) events occurred among individuals above the median predicted risk. When combining intrapartum factors, the area under the receiver operating curve increased to 0.729, (95% confidence interval, 0.693-0.764) and 171 (78%) events occurred among individuals above the median predicted risk. The significant factors that were associated with severe maternal morbidity in this combined model included the Expanded Obstetric Comorbidity Score, length of labor, and the presence of meconium-stained amniotic fluid. The area under the receiver operating curve for the model with intrapartum factors was significantly higher than the models using the Expanded Obstetric Comorbidity Score alone (P<.001).

CONCLUSION

The incorporation of intrapartum factors along with a validated risk tool (Expanded Obstetric Comorbidity Score) improved the ability to predict severe maternal morbidity at the start of the second stage. These findings emphasize the evolution of a woman's risk during her labor course and suggests that the prediction of maternal risk can be improved by considering intrapartum factors.

Refining the clinical definition of active phase arrest of dilation in nulliparous women to consider degree of cervical dilation as well as duration of arrest

BACKGROUND

Maternal and neonatal outcomes associated with duration of arrest of dilation beyond 4 hours are not well known. In addition, the current definition of arrest does not consider the degree of cervical dilation (6 cm vs 7 cm vs 8 cm vs 9 cm) when arrest occurs.

OBJECTIVE

We sought to examine maternal and neonatal outcomes in nulliparous women who achieved the active phase of labor according to the duration they required to achieve a cervical change of at least 1 cm (<4 hours vs 4-5.9 hours vs ≥6 hours) beginning at 6, 7, 8 and 9 cm.

STUDY DESIGN

This was a retrospective cohort study of nulliparous women with term singleton cephalic pregnancies in spontaneous or induced active labor (≥6 cm). To evaluate the effect of labor duration on maternal and fetal outcomes at different degrees of cervical dilation, we categorized women based on time intervals they required to achieve a cervical change of at least 1 cm after membrane rupture ("<4 hours," "4-5.9 hours," and "≥6 hours"), and we correlated each time interval with referent cervical dilation status (6 cm, 7 cm, 8 cm, and 9 cm). Maternal and neonatal outcomes were analyzed according to the duration to progress at least 1 cm starting from each degree of cervical dilation. Our primary outcome was a composite of neonatal outcomes, including intensive care unit admission, neonatal death, seizure, ventilator use, birth injury, and neonatal asphyxia. In addition, we examined maternal outcomes. Adjusted odds ratios with 95% confidence intervals were calculated, controlling for predefined covariates.

RESULTS

Of 31,505 nulliparous women included in this study, 13,142 (42%), 10,855 (34%), 11,761 (37%), and 17,049 (54%) reached documented cervical dilation of 6, 7, 8, and 9 cm, respectively. At cervical dilation of 6 or 7 cm, the arrest of dilation of <4 hours compared with arrest of dilation of 4 to 5.9 hours was associated with decreased risks of adverse maternal outcomes. When cervical dilation was 8 or 9 cm, arrest of dilation of <4 hours compared with arrest of dilation of 4 to 5.9 hours was associated with decreased risks of adverse maternal and neonatal outcomes. For example, women starting at a cervical dilation of 8 cm who required <4 hours to achieve a cervical change of 1 cm compared with those who required 4 to 5.9 hours had lower rates of cesarean delivery (adjusted odds ratio, 0.40; 95% confidence interval, 0.28-0.55), chorioamnionitis (adjusted odds ratio, 0.42; 95% confidence interval, 0.29-0.60), and the neonatal composite outcome (adjusted odds ratio, 0.51; 95% confidence interval, 0.36-0.72).

CONCLUSION

When cervical dilation is 6 or 7 cm, allowing arrest of dilation of ≥4 hours is reasonable because it was not associated with increased risks of adverse neonatal outcomes. When cervical dilation is 8 or 9 cm, the benefit of allowing arrest of dilation of ≥4 hours should be balanced against the risk of adverse maternal and neonatal outcomes.

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.

Analysis of Factors Associated With Variability and Acidosis of the Umbilical Artery pH at Birth

Background: Perinatal asphyxia is a significant contributing factor for neonatal morbidity and mortality. The aim of this study was to investigate the clinical factors associated with umbilical artery pH variability and fetal acidosis at birth. Methods: This is a single center cross-sectional study in a public regional hospital in southeastern Spain from January to December 2019. The reference population was 1.655 newborns, final sample of 312 experimental units with validated values of umbilical cord blood pH. Results: Factors such as gestational age at term ( X ¯ at - term : 7.26 ± 0.08- X ¯ no -_at-term: 7.31 ± 0.05, p: 0.00), primiparity ( X ¯ primiparity : 7.24 ± 0.078- X ¯ multiparity : 7.27 ± 0.08, p: 0.01), induced labor ( X ¯ induced : 7.24 ± 0.07- X ¯ spontaneous : 7.26 ± 0.081, p: 0.02), vaginal delivery ( X ¯ vaginal :7.25 ± 0.08- X ¯ cesarean :7.27 ± 0.07, p: 0.01), and prolonged dilation duration ( X ¯ AboveAverage : 7.22 ± 0.07- X ¯ BelowAverage : 7.27 ± 0.08, p: 0.00), expulsion duration ( X ¯ AboveAverage : 7.23 ± 0.07- X ¯ BelowAverage : 7.26 ± 0.08, p: 0.01), and total labor duration ( X ¯ AboveAverage : 7.23 ± 0.07- X ¯ BelowAverage : 7.27 ± 0.08, p: 0.00) are associated with a decrease in umbilical artery pH at birth. However, only three factors are associated with acidosis pH (<7.20) of the umbilical artery at birth: the induction of labor [OR: 1.74 (95% CI: 0.98-3.10); p: 0.04], vaginal delivery [OR: 2.09 (95% CI: 0.95-4.61); p: 0.04], and total duration of labor [OR: 2.06 (95% CI: 1.18-3.57); p: 0.01]. Conclusions: Although several factors may affect the variability of umbilical artery pH at birth by decreasing their mean values (gestational age, primiparity, induced labor, vaginal delivery and prolonged: dilation duration, expulsion duration and total labor duration), only induction of labor, vaginal delivery and total duration of labor are associated with an acidosis (<7.20) of same.

The impact of stage of labor on adverse maternal and neonatal outcomes in multiparous women: a retrospective cohort study

BACKGROUND

The correlation between stage of labor and adverse delivery outcomes has been widely studied. Most of studies focused on nulliparous women, it was not very clear what impact the stage of labor duration had on multiparous women.

METHODS

A retrospective cohort study was conducted among all the multiparous women of cephalic, term, singleton births, who planned vaginal delivery. The total stage of labor covered the first stage and the second stage in this study, and they were divided into subgroups. Adverse maternal outcomes were defined as referral cesarean delivery, instrumental delivery, postpartum hemorrhage, perineal laceration (III and IV degree), hospitalization stay ≥90th, and adverse neonatal outcomes as NICU, shoulder dystocia, Apgar score ≤ 7(5 min), neonatal resuscitation, assisted ventilation required immediately after delivery.

RESULTS

There were 7109 parturients included in this study. The duration of first stage was 6.2(3.6-10.0) hours, the second stage was 0.3(0.2-0.7) hour, the total stage was 6.9(4.1-10.7) hours in multiparous women. At the first stage, the rates of overall adverse outcome were 21, 23.4, 28.8, 35.5, 38.4% in subgroups < 6 h, 6-11.9 h, 12-17.9 h, 18-23.9 h, ≥24 h, which increased significantly (X² = 57.64, P < 0.001), and ARR (95% CI) were 1.10 (0.92,1.31), 1.33 (1.04,1.70), 1.80 (1.21,2.68), 2.57 (1.60,4.15) compared with subgroup < 6 h (ARR = 1); At the second stage, the rates of overall adverse outcome were 20.0, 30.7, 38.5, 61.2, 69.6% in subgroups < 1 h, 1-1.9 h, 2-2.9 h, 3-3.9 h, ≥4 h (X² = 349.70, P < 0.001), and ARR (95% CI) were 1.89 (1.50, 2.39), 2.22 (1.55, 3.18), 10.64 (6.09, 18.59), 11.75 (6.55, 21.08) compared with subgroup < 1 h (ARR = 1)). At the total stage, the rates of overall adverse outcome were 21.5, 30.8, 42.4% in subgroups < 12 h, 12-23.9 h, ≥24 h (X² = 84.90, P < 0.001), and ARR (95% CI) were 1.41 (1.16,1.72), 3.17 (2.10,4.80) compared with subgroup < 12 h (ARR = 1).

CONCLUSIONS

The prolonged stage of labor may lead to increased adverse outcomes in multiparous women, it was an independent risk factor of adverse maternal and neonatal outcomes.

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.

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.

"New or not-so-new" labor management practices and cesarean delivery for arrest of progress

BACKGROUND

Because nearly one-third of births in the United States are now achieved by cesarean delivery, comprising more than 1.27 million women each year, national organizations have recently published revised guidelines for the management of labor. These new guidelines stipulate that labor arrest should not be diagnosed unless ≥6 cm cervical dilatation has been reached or labor has been stimulated for at ≥6 hours.

OBJECTIVE

To determine the cervical dilatation and hours of labor stimulation prior to cesarean delivery for arrest of dilatation.

MATERIALS AND METHODS

Between January 1, 1999, andDecember 31, 2000, a prospective observational study of all primary cesarean deliveries was conducted at 13 university centers comprising the Eunice Kennedy Shriver National Institute for Child Health and Human Development, Maternal-Fetal Medicine Units Network. This secondary analysis includes all live-born, singleton, nonanomalous, cephalic gestations delivered by primary cesarean delivery at ≥37 weeks. A cesarean delivery was considered to have been performed for arrest of dilatation if the indication for the procedure was failure to progress, cephalopelvic disproportion, or failed induction. Augmentation was defined as stimulation after spontaneous labor had been previously diagnosed. Analysis included both the latent and active phases of labor. The active phase of labor was diagnosed when cervical dilatation was ≥4 cm in the presence of uterine contractions.

RESULTS

A total of 13,269 primary cesarean deliveries were available for analysis, 8,546 (65%) of which were performed for inadequate progress of labor with cervical dilatation recorded at the time of cesarean delivery. Of these cesarean deliveries for labor arrest, a total of 719 (8%) were performed in the latent phase of labor and 7827 (92%) were performed when cervical dilatation was ≥4 cm (active phase). Approximately two-thirds (n = =5876; 69%) received intrauterine pressure monitoring. A total of 5636 women (66% of those reaching the active phase of labor) had reached ≥6 cm cervical dilatation before cesarean delivery was performed. Moreover, 7440 (95%) of the 7827 women in active labor had ≥6 cm dilatation or had received labor stimulation ≥6 hours prior to cesarean delivery for arrest of dilatation.

CONCLUSION

Women undergoing primary cesarean delivery for arrest of dilatation 15 years before the recommendations of the Obstetrics Care Consensus had received bona fide efforts to achieve adequate labor consistent with the recommendations of the Consensus. Because 95% of these women had ≥6 cm dilatation or had received labor stimulation ≥6 hours prior to cesarean delivery for arrest of dilatation, these new recommendations are unlikely to change the cesarean delivery rates.

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.

Duration of labor and maternal and neonatal morbidity

BACKGROUND

Labor dystocia has been identified as a contributor to the rising cesarean delivery rate in the United States. Allowing more time for vaginal delivery, while being cognizant of maternal and neonatal outcomes, has been identified as a possible strategy to lower cesarean delivery rates.

OBJECTIVE

This study aimed to characterize the relationship between the duration of active phase and second-stage labor and maternal and neonatal morbidity.

STUDY DESIGN

We present a secondary analysis of the Consortium on Safe Labor project. From labors of 66,940 nonanomalous nulliparous term singleton vertex gestations, we excluded labors for which active phase (≥6 cm dilation) or second stage durations could not be calculated and from sites that did not report determinants of morbidity. For each duration of active phase or second stage labor (grouped in 1-hour increments), the adjusted maternal and neonatal composite morbidity was estimated by and compared with the morbidity associated with a duration <1 hour total and a duration of 1 hour shorter.

RESULTS

After exclusions, 48,144 deliveries remained. In adjusted models, compared with labor durations <1 hour total, maternal composite morbidity was significantly higher across active phase and second stage durations (both P<.001); neonatal composite morbidity was higher across the second stage (P<.001), but not active phase (P=.07) duration. These relationships appear linear with no apparent inflection point, and morbidity increases more rapidly. When compared with labor durations 1 hour shorter, significant differences persisted in maternal and neonatal composite morbidity in second stage labor only through 4 and 3 hours, respectively.

CONCLUSION

Maternal and neonatal composite morbidity is greater with longer durations of active and second stage labor; however, no clear cutoff point was determined to suggest truncation of either stage of labor for reasons of morbidity. In addition, incrementally higher morbidities that were noted vs duration <1 hour total were obscured when comparison was made with labors 1 hour shorter, which suggests that focusing on short differences in duration of labor may mask important underlying trends.

Efficacy and safety of misoprostol vaginal insert vs. oral misoprostol for induction of labor

Objectives To compare the oral application form of misoprostol with the misoprostol vaginal insert (MVI) in a Swiss cohort with special regards to the efficacy and safety. Methods We performed a retrospective case series including a historical group induced with oral misoprostol (MO, n=101) and an MVI group (n=101). The primary outcome was time to delivery. Secondary outcomes were mode of delivery, occurrence of tachysystole, use of analgesia and neonatal adverse outcome. Results A total of 202 women were included in the analysis (101 in the MVI as well as in the MO group). Time from start of induction to delivery was significantly shorter in the MVI group compared to the MO group (15.91 h vs. 37.68 h, P<0.001). Within the first 24 h, 78.2% of the women in the MVI group had given birth compared to 28.7% in the MO group (P<0.001). Tachysystole occurred more often in the MVI group (22.8% vs. 5.0%, P<0.001). Women in the MVI group more often needed opioid analgesia during the induction before onset of active labor (31.7% vs. 2.0%, P<0.001). There was no significant difference between neonatal outcomes in the two groups. Conclusion Time to delivery was significantly shorter in the MVI group with a higher rate of vaginal deliveries within the first 24 h. However, patients needed more opioids for pain relief during induction with MVI. There was no difference in neonatal outcomes.

Impact factors on cervical dilation rates in the first stage of labor

AIMS

To assess cervical dilation rates of nulliparous and multiparous women in the active first stage of labor and to evaluate significant impact factors.

METHODS

In a retrospective cohort study between January 2007 and July 2014 at the University Hospital of Zurich in Switzerland, we analyzed 8378 women with singleton pregnancies in vertex presentation with a vaginal delivery at 34+0 to 42+5 gestational weeks. Median cervical dilation rates were calculated and different impact factors evaluated.

RESULTS

Cervical dilation rates increase during labor progress with faster rates in multiparous compared with nulliparous women (P<0.001). Dilation rates exceed 1 cm/h at a dilatation of 6-7 cm, but are very individual. Accelerating impact factors are multiparity, a greater amount of cervical dilation and fetal occipitoanterior position, whereas the use of epidural anesthesia, a higher fetal weight and head circumference decelerate dilation (P<0.001).

CONCLUSION

Cervical dilation is a hyperbolic increasing process, with faster dilation rates in multiparous compared to nulliparous women and a reversal point of labor around 6-7 cm, respectively. Besides, cervical dilation is highly individual and affected by several impact factors. The diagnosis of labor arrest or prolonged labor should therefore be based on such rates and on the individual evaluation of every woman.

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.

Determination of antepartum and intrapartum risk factors associated with neonatal intensive care unit admission

OBJECTIVE

To determine antepartum and intrapartum factors that are associated with admission to neonatal intensive care unit (NICU) among infants delivered between 36.0 and 42.0 weeks at our institution.

METHODS

The retrospective cohort study included 73 consecutive NICU admissions and 375 consecutive non-NICU admissions. Data on demographic, antepartum, intrapartum and neonatal factors were collected. The primary endpoint defined was admission to NICU. Univariate analyses using the Student's t-test, Mann-Whitney U-test, χ2 Fisher's exact test was performed along with multivariate analysis of significant non-redundant variables.

RESULTS

Those with a significantly higher risk of NICU admission underwent induction of labor with prostaglandin analogs (12.5% vs. 24.7%, P=0.007). Length of first stage ≥720 min (33.5% vs. 51.9%, P=0.011), length of second stage of labor ≥240 min (10.6% vs. 31.6%, P<0.001) and prolonged rupture of membranes ≥120 min (54.0% vs. 80.0%, P=0.001) were all associated with an increased chance of NICU admission. Intrapartum factors predictive of NICU admission included administration of meperidine (11.7% vs. 27.4%, P<0.001), presence of preeclampsia (5.5% vs. 0.8%, P=0.015), use of intrapartum IV antihypertensives (1.1% vs. 13.7%, P<0.001), maternal fever (5.3% vs. 31.5%, P<0.001), fetal tachycardia (1.9% vs. 12.3%, P<0.001), and presence of meconium (30% vs. 8%, P<0.001).

CONCLUSION

Identification of modifiable risk factors may reduce neonatal morbidity and mortality. Results from this study can be used to develop and validate a risk model based on combined antepartum and intrapartum risk factors.

Regular Exercise Throughout Pregnancy is Associated with a Shorter First Stage of Labor

Purpose.

The aim of the present study was to examine the influence of moderate physical exercise throughout pregnancy on the duration of labor stages.

Design.

Study was a randomized controlled trial.

Setting.

The study took place at Hospital Puerta de Hierro and Hospital Severo Ochoa in Madrid, Spain.

Subjects.

We examined 166 pregnant women (31.6 ± 3.8 years), and all had uncomplicated and singleton gestation. Of these 83 were allocated to the exercise group (EG) and 83 to the control group (CG).

Intervention.

Women from the EG participated in a physical conditioning program throughout pregnancy, which included 55- to 60-minute sessions, 3 days per week.

Measures.

Pregnancy outcomes were measured: duration of labor stages, gestational age, weight gain, type of delivery, birth weight, birth size, head circumference, Apgar score, pH of umbilical cord.

Analysis.

Student's unpaired t-tests and χ2 tests were used; p values of < .05 indicated statistical significance. Cohen's d was used to determine the effect size.

Results.

Significant differences were found in the duration of the first stage of labor (EG = 389.6 ± 347.64 minutes vs. CG = 515.72 ± 353.36 minutes; p = .02, effect size Cohen's d = .36). The second and third stages did not differ between the study groups.

Conclusion.

A physical exercise program during pregnancy is associated with a shorter first stage of labor. These results may have important relevance to public health.

Elevated amniotic fluid lactate predicts labor disorders and cesarean delivery in nulliparous women at term

OBJECTIVE

We sought to assess amniotic fluid lactate (AFL) at diagnosis of spontaneous labor at term (≥37 weeks) as a predictor of labor disorders (dystocia) and cesarean delivery (CD).

STUDY DESIGN

This was a single-institution, prospective cohort study of 905 singleton, cephalic, term (≥37 weeks) nulliparous women in spontaneous labor. A standard management of labor (active management of labor) including a standard oxytocin regimen up to a maximum dose of 30 mU/min was applied. AFL was measured using a point-of-care device (LMU061; ObsteCare, Stockholm, Sweden). Labor arrest in the first stage of labor was defined as the need for oxytocin when cervical dilatation was <1 cm/h over 2 hours and in the second stage of labor by poor descent and rotation over 1 hour. Standard statistical analysis included analysis of variance, Pearson correlations, and binary logistic regression. Unsupervised decision tree analysis with 10-fold cross-validation was used to identify AFL thresholds.

RESULTS

AFL was normally distributed and did not correlate with age, body mass index, or gestation. Unsupervised decision tree analysis demonstrated that AFL could be divided into 3 groups: 0-4.9 mmol/L (n = 118), 5.0-9.9 mmol/L (n = 707), and ≥10.0 mmol/L (n = 80). Increasing AFL was associated with higher total oxytocin dose (P = .001), labor disorders (P = .005), and CD (P ≤ .001). Multivariable regression analysis demonstrated that women with AFL ≥5.0-9.9 mmol/L (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.06-2.39) and AFL ≥10.0 mmol/L (OR, 1.72; 95% CI, 1.01-2.93) were independent predictors of a labor disorder. AFL ≥5.0-9.9 mmol/L did not predict CD but multivariable analysis confirmed that AFL ≥10.0 mmol/L was an independent predictor of CD (OR, 3.35; 95% CI, 1.73-6.46). AFL ≥5.0-9.9 mmol/L had a sensitivity of 89% in predicting a labor disorder and a sensitivity of 93% in predicting CD with a 97% negative predictive value. AFL ≥10.0 mmol/L was highly specific but lacked sensitivity for CD. There was no difference in birthweight of infants according to labor disorder and delivery method.

CONCLUSION

AFL at diagnosis of labor in spontaneously laboring single cephalic nulliparous term women is an independent predictor of a labor disorder and CD. These data suggest that women with AFL between 5.0-9.9 mmol/L with a labor disorder may be amenable to correction using the active management of labor protocol.

Risk factors for serious morbidity in term nonanomalous neonates

OBJECTIVE

The purpose of this study was to identify ante- and intrapartum risk factors for serious morbidity in term nonanomalous neonates.

STUDY DESIGN

We analyzed the first 5000 subjects within an ongoing prospective cohort study of consecutive term births from 2010-2012. The primary outcome was a composite of serious neonatal morbidity defined as ≥1 cases of hypoxic ischemic encephalopathy, meconium aspiration with pulmonary hypertension, requirement of hypothermia therapy, respiratory distress syndrome, seizures, sepsis or suspected sepsis, or death. We calculated odds ratios for the composite morbidity that is associated with ante- and intrapartum factors. Multivariable logistic regression was used to estimate adjusted odds ratios.

RESULTS

Of 5000 term nonanomalous births, 393 had the composite morbidity. Significant risk factors for morbidity were nulliparity, presence of meconium, first stage of labor >95th percentile, second stage of labor >95th percentile, pregestational diabetes mellitus, chronic hypertension, obesity, maternal intrapartum fever, and cesarean delivery. In contrast, induction of labor and gestational age ≥41 weeks were not associated with significant morbidity.

CONCLUSION

We identified several significant risk factors for serious morbidity in term nonanomalous neonates. Clinicians may use these risk factors to help anticipate the potential need for additional neonatal support at delivery.

[Labor duration: from normality to dystocia]

"Normal" labor has been surprisingly little studied in the past 60 years even though it is a central axis in obstetrics. Standards were proposed 60 years ago by Emmanuel Friedman and adopted by many countries to become then, driven from Dublin school, the conditions allowing the management of labor: rupture of membranes and oxytocin with, in case of failure for dynamic dystocia, cesarean. Recent data have suggested that labor duration had changed since the 1960s. Changes in women's characteristics and in obstetric practice especially with the widespread use of oxytocin and realization of epidural may have an impact on labor duration. Current studies suggest that it may be possible to authorize longer labor duration without significant increase in maternal or neonatal morbidity. However, it is premature to change practices following the latest American recommendations without prior studies.

Weight gain in pregnancy: does the Institute of Medicine have it right?

OBJECTIVE

We aimed to examine whether women who adhered to Institute of Medicine (IOM) guidelines for gestational weight gain (GWG) had improved perinatal outcomes.

STUDY DESIGN

This is a population-based retrospective cohort study of nulliparous women with term singleton vertex births in the United States from 2011 through 2012. Women with medical or obstetric complications were excluded. Prepregnancy body mass index was calculated using reported weight and height. Women were categorized into 4 groups based on GWG and prepregnancy body mass index: (1) weight gain less than, (2) weight gain within, (3) weight gain 1-19 lb in excess of, and (4) weight gain ≥20 lb in excess of the IOM guidelines. The χ(2) test and multivariable logistic regression analysis were used for statistical comparisons.

RESULTS

Compared to women who had GWG within the IOM guidelines, women with excessive weight gain, particularly ≥20 lb, were more likely to have adverse maternal outcomes (preeclampsia: adjusted odds ratio [aOR], 2.78; 95% confidence interval [CI], 2.82-2.93; eclampsia: aOR, 2.51; 95% CI, 2.27-2.78; cesarean: aOR, 2.1; 95% CI, 2.14-2.19), blood transfusion (aOR, 1.22; 95% CI, 1.11-1.33), and neonatal outcomes (5-minute Apgar <4: aOR, 1.22; 95% CI, 1.14-1.31; ventilation use >6 hours: aOR, 1.24; 95% CI, 1.15-1.33; seizure: aOR, 1.53; 95% CI, 1.24-1.89). Women who gained less than IOM guidelines had lower risks of hypertensive disorders of pregnancy and obstetric interventions but were more likely to have small-for-gestational-age neonates (aOR, 1.55; 95% CI, 1.52-1.59).

CONCLUSION

Women whose GWG is in excess of IOM guidelines have higher risk of adverse maternal and neonatal outcomes, particularly in women with ≥20 lb excess weight gain above guidelines while women who had weight gain below the IOM guidelines were less likely to have maternal morbidity but had higher odds of small for gestational age.