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This protocol was amended on July 7, View the Summary of Protocol Amendments. Prolonged labor may increase the risk for maternal and neonatal infection, fetal distress, neonatal asphyxia, uterine rupture, and postpartum hemorrhage; it may also be a marker for an increased risk of maternal pelvic floor and genital trauma during delivery with a subsequent increase risk for future incontinence and pelvic organ prolapse and of shoulder dystocia.
These increased risks are the underlying indication for cesarean delivery in the setting of labor dystocia. On the other hand, cesarean delivery increases the risk of maternal hemorrhage, venous thromboembolism, and injury to the bladder and other internal organs, and can affect post-delivery mother-baby interactions. Furthermore, having one cesarean delivery increases the likelihood of having subsequent cesarean deliveries.
Abnormalities of labor progression are the single most common cause of primary cesarean delivery in the United States, accounting for over a third of procedures, 5 and uncertainty about optimal management of dystocia may play a major role in the well documented variation in cesarean delivery rates between hospitals that does not appear to be completely attributable to patient characteristics 6 although other factors not directly related to evidence on comparative effectiveness, such as patient and provider preferences, real or perceived malpractice concerns, and local practice norms may also be important factors.
Although there is no consensus on the "optimal" cesarean section rate conceptually, the rate which strikes a balance between harms and benefits for both mother and baby that is considered acceptable to most patients , there is widespread consensus that current rates in the United States are too high. One source of uncertainty in the evidence is that the definitions for different phases of labor, and what constitutes "normal" labor, vary across studies and likely in practice as well.
The definition of "normal" may vary across different populations and may depend on whether "normality" is based on a specified quantile of the distribution of rates of cervical change in the first stage of labor or rate of fetal descent in the second stage of labor, or on maternal and neonatal outcomes.
Another source of uncertainty is that there are complex trade-offs between patient preferences for the labor and delivery process, on the one hand, and outcomes on the other. These considerations involve issues related to setting home, birthing center, hospital , provider lay midwife, nurse-midwife, family physician, obstetrician , and available technology including analgesia, fetal heart rate monitoring, and measurement of intrauterine pressure.
The draft key questions KQs developed during Topic Refinement were available for public comment from September 2, , to September 22, The public comments focused on clarifying populations primarily clarifying that women undergoing induction of labor, or who had experienced prior cesarean delivery, are excluded from this review , explicitly listing several setting comparisons site of care or provider , expanding the outcomes to include neonatal length of stay, and clarifying the "reference" cervical examination frequency.
There were also recommendations to consider a review that incorporates a range of clinical and non-clinical studies. Overall, the comments affirmed our planned approach. There were no other significant changes to the KQs or proposed methods. Do delivery outcomes for management of abnormal labor differ based on the criteria used to define protracted or arrested labor at different stages of the labor process?
What are the benefits and harms of supportive care measures, including ambulation, nutrition, hydration, and emotional support during spontaneous labor? What are the benefits and harms of epidural analgesia in labor, particularly in terms of the risk of a diagnosis of prolonged labor? How does the frequency of cervical examination affect the probability of specific benefits and harms?
What are the benefits and harms of intrauterine pressure catheters in the diagnosis and management of labor dystocia? For women with abnormal labor, what are the relative benefits and harms of high- vs. For women in spontaneous labor undergoing augmentation with oxytocin, what are the relative benefits and harms in terms of both maternal and neonatal outcomes of electronic fetal monitoring vs intermittent auscultation?
For women in the second stage of labor, is there a benefit from delayed or Valsalva pushing for time to delivery or mode of delivery?
Women aged with uncomplicated pregnancy at weeks gestation with a singleton pregnancy with vertex presentation and no prior history of cesarean delivery who have begun spontaneous labor defined as the onset of spontaneous contractions—women who present with spontaneous rupture of membranes without contractions are not included in the review.
For the purposes of this review, women who are undergoing induction of labor for any indication are excluded, because the probability of specific outcomes is necessarily different for them.
Definitions of abnormalities of the latent and active phases of the first stage of labor up until complete dilation of the cervix and of the second stage of labor from complete dilation until delivery of the infant , developed based on data from the Safe Labor Consortium. No amniotomy, amniotomy for specific indications e. Ambulation, routine maternal oxygen supplementation, specific nutritional recommendations or limitations, specific oral or parenteral hydration recommendations or limitations, continuous emotional support, peanut ball, Lamaze, hypnobirthing, hydrotherapy, positioning, acupuncture, other nonpharmacologic interventions identified through the search.
No analgesia, other methods of analgesia e. Cervical examination only in the setting of clinical concern about labor progress; regular cervical examinations at differing frequencies.
Women aged with uncomplicated pregnancy at weeks with suspected abnormalities of the first stage of labor. Women aged with uncomplicated pregnancy at weeks with a diagnosed abnormality of the first stage of labor. High-dose oxytocin; nipple stimulation; maternal oxygen supplementation as an adjunct to oxytocin; different formulations of oxytocin.
Women aged with uncomplicated pregnancy at weeks gestation with a diagnosed abnormality of the first stage of labor undergoing augmentation with oxytocin. Women aged with uncomplicated pregnancies at weeks who have reached complete cervical dilation with or without augmentation ; relevant subgroups include women with and without epidural analgesia.
The analytic framework presented in Figure 1 illustrates the population, interventions, outcomes, and adverse effects that will guide the literature search and synthesis.
This figure illustrates the progression of spontaneous labor, which may be affected by interventions or management strategies performed prior to the diagnosis of abnormal progression; the criteria used to diagnose abnormal progression; and interventions performed after the diagnosis of abnormal progression. In developing this comprehensive review, we will apply the rules of evidence and evaluation of strength of evidence recommended by the Agency for Healthcare Research and Quality AHRQ in its Methods Guide for Effectiveness and Comparative Effectiveness Reviews hereafter referred to as the Methods Guide.
We will seek the input of an external Technical Expert Panel TEP when warranted to aid in identifying the outcomes of critical importance for assessment. In addition to teleconference discussions, this input would be anticipated to take the form of formal surveys and numerical ranking.
These databases were selected based on internal expert opinion that they would identify most of the relevant literature on this topic, and reflects the databases used in related systematic reviews, particularly reviews conducted by the Cochrane Pregnancy and Childbirth Group.
Our proposed search strategy for PubMed is provided in the Appendix; this strategy will be adapted as appropriate for searching the other databases. Where possible, we will use existing validated search filters such as the Clinical Queries Filters in PubMed. An experienced search librarian will guide all searches. We will supplement the electronic searches with a manual search of citations from a set of key primary and review articles. The reference list for identified key articles will be manually hand-searched and cross-referenced against our database, and additional relevant manuscripts will be retrieved.
As a mechanism to ascertain publication bias in recent studies, we will search ClinicalTrials. While the draft report is under peer review, we will update the search and include any eligible studies identified either during that search or through peer or public reviews in the final report.
We will use several approaches to identifying relevant gray literature, including notification to stakeholders including drug and device manufacturers of requests to submit scientific information packets and a search of U. We will also search study registries for relevant articles from completed studies. Gray literature databases will include ClinicalTrials. Inclusion at the title screening level will be liberal; if a single reviewer believes an article may contain relevant information based on title, the article will move to the next level abstract for further screening.
Articles included by either reviewer will undergo full-text screening. Disagreements that cannot be resolved by the two reviewers will be resolved by a third expert member of the team. Articles meeting eligibility criteria see Table 1 will be included for data abstraction.
We will make screening decisions and abstract data based on the published literature and available online appendices. We will not contact study authors for additional data. The research team will create data abstraction forms for the KQs that will be programmed in the DistillerSR software. Based on their clinical and methodological expertise, a pair of researchers will be assigned to abstract data from each of the eligible articles. One researcher will abstract the data, and the second will over-read the article and the accompanying abstraction to check for accuracy and completeness.
Disagreements will be resolved by consensus or by obtaining a third reviewer's opinion if consensus cannot be reached. We will link studies to avoid duplication of patient cohorts. Guidance documents will be drafted and provided to the researchers to aid both reproducibility and standardization of data collection.
We will design the data abstraction forms for this project to collect the data required to evaluate the specified eligibility criteria for inclusion in this review, as well as demographic and other data needed for determining outcomes intermediate, final, and adverse events outcomes. We will pay particular attention to describing the details of the treatment e. In addition, we will describe comparators carefully, as treatment standards may have changed during the period covered by the review.
The safety outcomes will be framed to help identify adverse events, including those from drug therapies and those resulting from misdiagnosis and labeling. Data necessary for assessing quality and applicability, as described in the Methods Guide, 20 will also be abstracted. Before they are used, abstraction form templates will be pilot-tested with a sample of included articles to ensure that all relevant data elements are captured and that there is consistency and reproducibility between abstractors.
Forms will be revised as necessary before full abstraction of all included articles. During abstraction, we will assess methodological quality, or risk of bias, for each individual study based on the Cochrane Risk of Bias 21 tool for randomized studies, and the Newcastle-Ottawa Scale 22 for observational studies.
We will supplement these tools with additional assessment questions, such as use of appropriate analysis, based on recommendations in the AHRQ's Methods Guide.
Disagreements will be resolved as described above, either by consensus or by obtaining a third reviewer's opinion if consensus cannot be reached. For all studies, the overall study quality will be assessed as follows:.
The grading will be outcome-specific such that a given study that analyzes its primary outcome well but did an incomplete analysis of a secondary outcome would be assigned a different quality grade for each of the two outcomes. Studies of different designs will be graded within the context of their respective designs. Thus, RCTs will be graded good, fair, or poor, and observational studies will separately be graded good, fair, or poor.
We will begin by summarizing key features of the included studies for each KQ. To the degree that data are available, we will abstract information on study design; patient characteristics; clinical settings; interventions; and intermediate, final, and adverse event outcomes.
One potentially important consideration is the effect of changing diagnostic thresholds on estimates of comparative effectiveness in terms of both benefits and harms.
It is possible that more conservative definitions of labor dystocia based on more recent evidence would substantially change the probability of an adverse outcome because of differences in sensitivity and specificity compared to older criteria, which would have the effect of changing both the expected probability of events and the absolute number of events.
This in turn could have substantial impact on the precision of effect estimates, as well as on estimates of the absolute effect including number needed to treat or harm. We will carefully assess the implications of this using the available evidence through simple modeling, and discuss any necessary amendments to the protocol with AHRQ and the TEP. We will then determine the feasibility of completing a quantitative synthesis i.
For a meta-analysis, feasibility depends on the volume of relevant literature, conceptual homogeneity of the studies, completeness of the reporting of results, and the adequacy and completeness of any existing meta-analyses. Because there are a large number of existing systematic reviews for this topic, particularly from the Cochrane Collaboration, we will consider these results using suggested guidance from the Methods Guide chapter on integrated bodies of evidence, 23 as outlined in more detail below.
When a meta-analysis is appropriate, we will use random-effects models to synthesize the available evidence quantitatively. We will test for heterogeneity using graphical displays and test statistics Q and I 2 statistics , while recognizing that the ability of statistical methods to detect heterogeneity may be limited.
For comparison, we will also perform fixed-effect meta-analyses. We will present summary estimates, standard errors, and confidence intervals. We anticipate that intervention effects may be heterogeneous. We hypothesize that the methodological quality of individual studies, study type, the characteristics of the comparator, and patients' underlying clinical presentation will be associated with the intervention effects.
We will perform quantitative and qualitative syntheses separately by study type and discuss their consistency qualitatively. For a decision analysis or simulation model, feasibility will be based on a judgment about the degree to which such an analysis will provide additional insight into the KQs based on the available evidence—for example, a stochastic simulation of the likelihoods of caesarian delivery based on two different criteria for diagnosis of abnormal labor based on distributions of labor progression in a large population would give insight into the existing degree of certainty about the benefit-harm trade-off associated with each protocol, which would inform future research prioritization.
We will grade the strength of evidence for each outcome assessed; thus, the strength of evidence for two separate outcomes in a given study may be graded differently. Additional domains to be used when appropriate most relevant to observational studies are dose-response association, impact of plausible residual confounders, and strength of association magnitude of effect.
When the body of evidence for a particular outcome includes both RCTs and observational studies, we will grade each study type separately using design-specific criteria.
Dystocia and Augmentation of Labor
The report provides a review of the definition of dystocia, the risk factors associated with dystocia, the criteria that require delivery, and the approaches to clinical management of labor complicated by dystocia. It focuses on labor subsequent to entering the active phase, diagnosis of active-phase abnormalities, clinical considerations, and management recommendations for the active phase and the second stage of labor. Dystocia is characterized by the slow and abnormal progression of labor and is the leading indication for primary cesarean delivery in the United States. Dystocia should not be diagnosed until an adequate trial of labor has been achieved.
This protocol was amended on July 7, View the Summary of Protocol Amendments. Prolonged labor may increase the risk for maternal and neonatal infection, fetal distress, neonatal asphyxia, uterine rupture, and postpartum hemorrhage; it may also be a marker for an increased risk of maternal pelvic floor and genital trauma during delivery with a subsequent increase risk for future incontinence and pelvic organ prolapse and of shoulder dystocia. These increased risks are the underlying indication for cesarean delivery in the setting of labor dystocia. On the other hand, cesarean delivery increases the risk of maternal hemorrhage, venous thromboembolism, and injury to the bladder and other internal organs, and can affect post-delivery mother-baby interactions. Furthermore, having one cesarean delivery increases the likelihood of having subsequent cesarean deliveries.