Little is known about the effects of the Chronic Care Model (CCM) and community health workers (CHWs) on pharmacotherapy of type 2 diabetes and hypertension in resource-poor settings. This retrospective cohort implementation study evaluated the effects of a community-based program consisting of CCM, CHWs, guidelines-based treatment protocols, and inexpensive freely accessible medications on type 2 diabetes and hypertension pharmacotherapy quality. A door-to-door household survey identified 856 adults 35 years of age and older living in a low-income Peruvian community, of whom 83% participated in screening for diabetes and hypertension. Patients with confirmed type 2 diabetes and/or hypertension participated in the program's weekly to monthly visits for < = 27 months. The program was implemented as two care periods employed sequentially. During home care, CHWs made weekly home visits and a physician made treatment decisions remotely. During subsequent clinic care, a physician attended patients in a centralized clinic. The study compared the effects of program (pre- versus post-) (N = 262 observations), and home versus clinic care periods (N = 211 observations) on standards of treatment with hypoglycemic and antihypertensive agents, angiotensin converting enzyme inhibitors, and low-dose aspirin. During the program, 80% and 50% achieved hypoglycemic and antihypertensive standards, respectively, compared to 35% and 8% prior to the program, RRs 2.29 (1.72-3.04, p <0.001) and 6.64 (3.17-13.9, p<0.001). Achievement of treatment standards was not improved by clinic compared to home care (RRs 1.0 +/- 0.08). In both care periods, longer retention in care (>50% of allowable time) was associated with achievement of all treatment standards. 85% compared to 56% achieved the hypoglycemic treatment standard with longer and shorter retention, respectively, RR 1.52 (1.13-2.06, p<0.001); 56% compared to 27% achieved the antihypertensive standard, RR 2.11 (1.29-3.45, p<0.001). In a dose-dependent manner, the community-based program was associated with improved guidelines-based pharmacotherapy of type 2 diabetes and hypertension.

It is widely assumed that fetal ischemic brain injury during labor derives almost exclusively from severe, systemic hypoxemia with marked neonatal depression and acidemia.Severe asphyxia, however, is one of several causes of perinatal neurological injury and may not be the most common; most neonates diagnosed with hypoxic-ischemic encephalopathy do not have evidence of severe asphyxia.Sepsis, direct brain trauma, and drug or toxin exposure account for some cases, while mechanical forces of labor and delivery that increase fetal intracranial pressure sufficiently to impair brain perfusion may also contribute.Because of bony compliance and mobile suture lines, the fetal skull changes shape and redistributes cerebrospinal fluid during labor according to constraints imposed by contractions, and bony and soft tissue elements of the birth canal as the head descends.These accommodations, including the increase in intracranial pressure, are adaptive and necessary for efficient descent of the head while safeguarding cerebral blood flow.Autonomic reflexes mediated through central receptors normally provide ample protection of the brain from the considerable pressure exerted on the skull.On occasion, those forces, which are transmitted intracranially, may overcome the various adaptive anatomical, cardiovascular, metabolic, and neurological mechanisms that maintain cerebral perfusion and oxygen availability, resulting in ischemic brain injury.Accepting the notion of a potentially adverse impact of fetal head compression suggests that avoidance of excessive uterine activity and of relentless pushing without steady progress in descent may offer protection for the fetal brain during parturition.Excessive head compression should be considered in the differential diagnosis of ischemic encephalopathy.

The second stage of labor extends from complete cervical dilatation to delivery. During this stage, descent and rotation of the presenting part occur as the fetus passively negotiates its passage through the birth canal. Generally, descent begins during the deceleration phase of dilatation as the cervix is drawn upward around the fetal presenting part. The most common means of assessing the normality of the second stage of labor is to measure its duration, but progress can be more meaningfully gauged by measuring the change in fetal station as a function of time. Accurate clinical identification and evaluation of differences in patterns of fetal descent are necessary to assess second stage of labor progress and to make reasoned judgments about the need for intervention. Three distinct graphic abnormalities of the second stage of labor can be identified: protracted descent, arrest of descent, and failure of descent. All abnormalities have a strong association with cephalopelvic disproportion but may also occur in the presence of maternal obesity, uterine infection, excessive sedation, and fetal malpositions. Interpretation of the progress of fetal descent must be made in the context of other clinically discernable events and observations. These include fetal size, position, attitude, and degree of cranial molding and related evaluations of pelvic architecture and capacity to accommodate the fetus, uterine contractility, and fetal well-being. Oxytocin infusion can often resolve an arrest or failure of descent or a protracted descent caused by an inhibitory factor, such as a dense neuraxial block. It should be used only if thorough assessment of fetopelvic relationships reveals a low probability of cephalopelvic disproportion. The value of forced Valsalva pushing, fundal pressure, and routine episiotomy has been questioned. They should be used selectively and where indicated.

The active phase of labor begins at various degrees of dilatation when the rate of dilatation transitions from the relatively flat slope of the latent phase to a more rapid slope. No diagnostic manifestations demarcate its onset, other than accelerating dilatation. It ends with apparent slowing of dilatation, a deceleration phase, which is usually short in duration and frequently undetected. Several aberrant labor patterns can be detected during the active phase, including protracted dilatation, arrest of dilatation, prolonged deceleration phase and failure of descent. Underlying factors may include cephalopelvic disproportion, excessive neuraxial block, poor uterine contractility, fetal malpositions, malpresentations, uterine infection, maternal obesity, advanced maternal age and previous cesarean delivery. When an active-phase disorder is identified, cesarean delivery is justifiable if there is compelling clinical evidence of disproportion. A prolonged deceleration disorder is strongly associated with disproportion and second stage abnormalities. Shoulder dystocia may occur if vaginal delivery eventuates. This review discusses several issues raised by the introduction of new clinical practice guidelines for labor management.

The latent phase of labor extends from the initiation of labor to the onset of the active phase. Because neither margin is always precisely identifiable, the duration of the latent phase often can only be estimated. During this phase, the cervix undergoes a process of rapid remodeling, which may have begun gradually weeks before. As a consequence of extensive changes in its collagen and ground substance, the cervix softens, becomes thinner and dramatically more compliant, and may dilate modestly. All of these changes prepare the cervix for the more rapid dilatation that will occur during the active phase to follow. For the clinician, it is important to recognize that the latent phase may normally extend for many hours. The normal limit for the duration of the latent phase should be considered to be approximately 20 hours in a nullipara and 14 hours in a multipara. Factors that have been associated with a prolonged latent phase include deficient prelabor or intrapartum cervical remodeling, excessive maternal analgesia or anesthesia, maternal obesity, and chorioamnionitis. Approximately 10% of women with a prolonged latent phase are actually in false labor, and their contractions eventually abate spontaneously. The management of a prolonged latent phase involves either augmenting uterine activity with oxytocin or providing a sedative-induced period of maternal rest. Both are equally effective in advancing the labor to active phase dilatation. A very long latent phase may be a harbinger of other labor dysfunctions.

There is no doubt that parturition can produce fetal and neonatal adversity, but the frequency with which this occurs is uncertain, particularly in modern healthcare settings. Moreover, there is a paucity of recent studies in this area. Substantial challenges impede epidemiologic study of the effect of parturition on offspring. Randomized trials would be ethically fraught. Therefore, large observational samples with detailed data concerning labor and delivery events are needed. Importantly, long-term follow-up of infants is necessary to reach reliable conclusions. Few such data sets exist, and it is difficult, expensive, and time-consuming to create and to study them. Reports of immediate newborn condition in relation to the antecedent labor are helpful, but this evidence is an imperfect predictor of long-term neurologic status. In this review, we endeavor to summarize existing information about the relationship between objectively defined abnormalities of labor progress and long-term disability in offspring. The only data available are from collected experiential information on outcomes stratified according to labor and delivery events. Most studies do not ensure against confounding by the many concurrent conditions that may affect outcome, or use inconsistent criteria to define abnormal labor. According to the best available evidence, dysfunctional labor patterns are potentially associated with poor outcomes for surviving infants. The question of whether these adverse effects can be mitigated by early diagnosis and expeditious management deserves to be answered, but cannot be at this time. In the absence of more conclusive results from well-designed studies, we can conclude that the best interests of offspring are served by adhering to evidence-based paradigms for the prompt identification and treatment of dysfunctional labor patterns.

Cesarean birth has increased substantially in many parts of the world over recent decades and concerns have been raised about the propriety of this change in obstetric practice. Sometimes, a cesarean is necessary to preserve fetal and maternal health. But in balancing the risks of surgical intervention the implicit assumption has been that cesarean birth is an equivalent alternative to vaginal birth from the standpoint of the immediate and long-term health of the fetus and neonate. Increasingly, we realize this is not necessarily so. Delivery mode per se may influence short-term and abiding problems with homeostasis in offspring, quite independent of the indications for the delivery and other potentially confounding factors. The probability of developing various disorders, including respiratory compromise, obesity, immune dysfunction, and neurobehavioral disorders has been shown in some studies to be higher among individuals born by cesarean. Moreover, many of these adverse effects are not confined to the neonatal period and may develop over many years. Although the associations between delivery mode and long-term health are persuasive, their pathogenesis and causality remain uncertain. Full exploration and a clear understanding of these relationships is of great importance to the health of offspring.

Electronic fetal monitoring (EFM) was introduced into obstetric practice in 1970 as a test to identify early deterioration of fetal acid-base balance in the expectation that prompt intervention ("rescue") would reduce neonatal morbidity and mortality. Clinical trials using a variety of visual or computer-based classifications and algorithms for intervention have failed repeatedly to demonstrate improved immediate or long-term outcomes with this technique, which has, however, contributed to an increased rate of operative deliveries (deemed "unnecessary"). In this review, we discuss the limitations of current classifications of FHR patterns and management guidelines based on them. We argue that these clinical and computer-based formulations pay too much attention to the detection of systemic fetal acidosis/hypoxia and too little attention not only to the pathophysiology of FHR patterns but to the provenance of fetal neurological injury and to the relationship of intrapartum injury to the condition of the newborn. Although they do not reliably predict fetal acidosis, FHR patterns, properly interpreted in the context of the clinical circumstances, do reliably identify fetal neurological integrity (behavior) and are a biomarker of fetal neurological injury (separate from asphyxia). They provide insight into the mechanisms and trajectory (evolution) of any hypoxic or ischemic threat to the fetus and have particular promise in signaling preventive measures (1) to enhance the outcome, (2) to reduce the frequency of "abnormal" FHR patterns that require urgent intervention, and (3) to inform the decision to provide neuroprotection to the newborn.

The term "evidence-based medicine" emerged in the late 1980s and has since become ever more prominent in our lexicon.1Eddy D.M. Billings J. The quality of medical evidence: implications for quality of care.Health Aff (Millwood). 1988; 7: 19-32Google Scholar,2Djulbegovic B. Guyatt G.H. Progress in evidence-based medicine: a quarter century on.Lancet. 2017; 390: 415-423Google Scholar Its basic premise—namely, that decisions about patient care should be based on the best available objective evidence—is unassailable. That perspective has helped focus the work of practicing physicians, investigators, and medical policy-making bodies in guiding both direct care and the development of rational and informed medical practice recommendations. Of course, using the best available evidence for decision-making in medicine is hardly a new concept. Good clinicians have always done so, even long before the current age of randomized clinical trials and cutting-edge methods for statistical testing. But medical history has been generous in providing the hard lessons that even the best available evidence—and even more so, substandard evidence—might turn out to be problematic.3Afshari A. De Hert S. Pitfalls of clinical practice guidelines in the era of broken science: let's raise the standards.Eur J Anaesthesiol. 2018; 35: 903-906Google Scholar, 4Kung J. Miller R.R. Mackowiak P.A. Failure of clinical practice guidelines to meet Institute of Medicine standards: two more decades of little, if any, progress.Arch Intern Med. 2012; 172: 1628-1633Google Scholar, 5Shaneyfelt T. In guidelines we cannot trust.Arch Intern Med. 2012; 172: 1633-1634Google Scholar, 6Graham R, Mancher M, Wolman DM, Greenfield S, Steinberg E. Clinical practice guidelines we can trust. Institute of Medicine. Washington, DC: National Academies Press; 2011.Google Scholar Clinical practice guidelines (CPGs) based on such evidence may prove to be misleading and even harmful.7Rosenbloom J.I. Stout M.J. Tuuli M.G. et al.New labor management guidelines and changes in cesarean delivery patterns.Am J Obstet Gynecol. 2017; 217: 689.e1-689.e8Google Scholar, 8Chaillet N. Dumont A. Abrahamowicz M. et al.A cluster-randomized trial to reduce cesarean delivery rates in Quebec.N Engl J Med. 2015; 372: 1710-1721Google Scholar, 9Neal J.L. Lowe N.K. Phillippi J.C. Carlson N.S. Knupp A.M. Dietrich M.S. Likelihood of cesarean birth among parous women after applying leading active labor diagnostic guidelines.Midwifery. 2018; 67: 64-69Google Scholar, 10Bernitz S. Dalbye R. Zhang J. et al.The frequency of intrapartum caesarean section use with the WHO partograph versus Zhang's guideline in the Labour Progression Study (LaPS): a multicentre, cluster-randomised controlled trial.Lancet. 2019; 26: 340-348Google Scholar, 11Thuillier C. Roy S. Peyronnet V. Quibel T. Nlandu A. Rozenberg P. Impact of recommended changes in labor management for prevention of the primary cesarean delivery.Am J Obstet Gynecol. 2018; 218: 341.e1-341.e9Google Scholar, 12Zipori Y. Grunwald O. Ginsberg Y. Beloosesky R. Weiner Z. The impact of extending the second stage of labor to prevent primary cesarean delivery on maternal and neonatal outcomes.Am J Obstet Gynecol. 2019; 220: 191.e1-191.e7Google Scholar For us to have confidence in their results, studies that assess evidence must meet 2 essential criteria: first, the evidence base needs to be sound (ie, it must contain unbiased, accurate, complete, and appropriately collected information); and second, the data analysis has to be trustworthy (ie, done thoroughly and by acceptable, substantive, reliable, and correctly applicable means). CPGs13Obstetric Care Consensus No. 1: safe prevention of the primary cesarean delivery.Obstet Gynecol. 2014; 123: 693-711Google Scholar for the management of labor were formulated and published by the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine (ACOG/SMFM) about a decade ago. They were based, in large part, on the findings of Zhang et al.14Zhang J. Troendle J.F. Yancey M.K. Reassessing the labor curve in nulliparous women.Am J Obstet Gynecol. 2002; 187: 824-828Google Scholar, 15Vahratian A. Troendle J.F. Siega-Riz A.M. Zhang J. Methodological challenges in studying labour progression in contemporary practice.Paediatr Perinat Epidemiol. 2006; 20: 72-78Google Scholar, 16Zhang J. Troendle J. Mikolajczyk R. Sundaram R. Beaver J. Fraser W. The natural history of the normal first stage of labor.Obstet Gynecol. 2010; 115: 705-710Google Scholar, 17Laughon S.K. Branch D.W. Beaver J. Zhang J. Changes in labor patterns over 50 years.Am J Obstet Gynecol. 2012; 206: 419.e1-419.e9Google Scholar, 18Zhang J. Troendle J. Grantz K.L. Reddy U.M. Statistical aspects of modeling the labor curve.Am J Obstet Gynecol. 2015; 212: 750.e1-750.e4Google Scholar, 19Zhang J. Duan T. The physiologic pattern of normal labour progression.BJOG. 2018; 125: 955Google Scholar The CPGs seem to have been devised, adopted, published, and disseminated without, at minimum, the pretesting necessary to satisfy the fundamental tenets of evidence-based medicine. The World Health Organization (WHO)20World Health Organization. Maternal health and safe motherhood programme. Preventing prolonged labor: a Practical Guide. Geneva, Switzerland: The Partograph. World Health Organization; 1994.Google Scholar, 21WHO labor care Guide. WHO Labour Care Guide: User's Manual. World Health Organization, Geneva2021Google Scholar, 22Hofmeyr G.J. Bernitz S. Bonet M. et al.WHO next-generation partograph: revolutionary steps towards individualised labour care.BJOG. 2021; 128: 1658-1662Google Scholar modified its own popular partograph to incorporate many of the new CPGs' recommendations, thereby accelerating their spread. In the years that have elapsed since the CPGs were first made public, several clinical studies7Rosenbloom J.I. Stout M.J. Tuuli M.G. et al.New labor management guidelines and changes in cesarean delivery patterns.Am J Obstet Gynecol. 2017; 217: 689.e1-689.e8Google Scholar, 8Chaillet N. Dumont A. Abrahamowicz M. et al.A cluster-randomized trial to reduce cesarean delivery rates in Quebec.N Engl J Med. 2015; 372: 1710-1721Google Scholar, 9Neal J.L. Lowe N.K. Phillippi J.C. Carlson N.S. Knupp A.M. Dietrich M.S. Likelihood of cesarean birth among parous women after applying leading active labor diagnostic guidelines.Midwifery. 2018; 67: 64-69Google Scholar, 10Bernitz S. Dalbye R. Zhang J. et al.The frequency of intrapartum caesarean section use with the WHO partograph versus Zhang's guideline in the Labour Progression Study (LaPS): a multicentre, cluster-randomised controlled trial.Lancet. 2019; 26: 340-348Google Scholar, 11Thuillier C. Roy S. Peyronnet V. Quibel T. Nlandu A. Rozenberg P. Impact of recommended changes in labor management for prevention of the primary cesarean delivery.Am J Obstet Gynecol. 2018; 218: 341.e1-341.e9Google Scholar, 12Zipori Y. Grunwald O. Ginsberg Y. Beloosesky R. Weiner Z. The impact of extending the second stage of labor to prevent primary cesarean delivery on maternal and neonatal outcomes.Am J Obstet Gynecol. 2019; 220: 191.e1-191.e7Google Scholar (of various designs, size, and quality) have been published dealing with the impact of introducing them. Investigative results have been widely divergent and inconsistent with respect to cesarean delivery rates (ranging from lower to no difference and to higher) and maternal and fetal-neonatal adverse effects (ranging from fewer to no impact and to greater impact). In overview, given these findings, we feel that the CPGs for labor management have not fully met their stated objectives—and implied promise—of substantially reducing the cesarean delivery rate and doing so safely. The unconvincing results require frank inquiry into why that occurred. Our entreaties23Cohen W.R. Friedman E.A. Perils of the new labor management guidelines.Am J Obstet Gynecol. 2015; 212: 420-427Google Scholar, 24Cohen W.R. Friedman E.A. Misguided guidelines for managing labor.Am J Obstet Gynecol. 2015; 212: 753.e1-753.e3Google Scholar, 25Cohen W.R. Sumersille M. Friedman E.A. Management of labor: are the new guidelines justified?.J Midwifery Womens Health. 2018; 63: 10-13Google Scholar, 26Cohen W.R. Friedman E.A. The assessment of labor: a brief history.J Perinat Med. 2018; 46: 1-8Google Scholar, 27Cohen W.R. Friedman E.A. Obstetric practice guidelines: labor's love lost.J Matern Fetal Neonatal Med. 2019; 32: 1567-1570Google Scholar, 28Cohen W.R. Friedman E.A. Guidelines for labor assessment: failure to progress?.Am J Obstet Gynecol. 2020; 222: 342.e1-342.e4Google Scholar have not yielded any response or remedial change thus far. As mentioned above, the CPGs on labor management were based largely on the findings of Zhang et al,14Zhang J. Troendle J.F. Yancey M.K. Reassessing the labor curve in nulliparous women.Am J Obstet Gynecol. 2002; 187: 824-828Google Scholar, 15Vahratian A. Troendle J.F. Siega-Riz A.M. Zhang J. Methodological challenges in studying labour progression in contemporary practice.Paediatr Perinat Epidemiol. 2006; 20: 72-78Google Scholar, 16Zhang J. Troendle J. Mikolajczyk R. Sundaram R. Beaver J. Fraser W. The natural history of the normal first stage of labor.Obstet Gynecol. 2010; 115: 705-710Google Scholar, 17Laughon S.K. Branch D.W. Beaver J. Zhang J. Changes in labor patterns over 50 years.Am J Obstet Gynecol. 2012; 206: 419.e1-419.e9Google Scholar, 18Zhang J. Troendle J. Grantz K.L. Reddy U.M. Statistical aspects of modeling the labor curve.Am J Obstet Gynecol. 2015; 212: 750.e1-750.e4Google Scholar, 19Zhang J. Duan T. The physiologic pattern of normal labour progression.BJOG. 2018; 125: 955Google Scholar who described a statistical method for determining labor progression. We have questioned the validity and reliability of their system, the database used to study it, and the data and labor curves that were derived from its application; and we have raised issues about the trustworthiness of the guidelines for labor management created by ACOG/SMFM because they were based on Zhang et al's studies What is disturbing about this development is not the controversy, because different viewpoints are healthy drivers of intellectual growth in our specialty, as in all others. What troubles us is that the promulgation and adoption of the labor management guidelines challenged the fundamental precepts of evidence-based medicine. It is never inappropriate to reassess long-standing policies. Many do not stand the test of time well. Often, new developments in basic science, better designed clinical trials, or even the evaluation of what is now called real-world evidence, serve to correct misconceptions, identify defects in study design or analysis, or incorporate newly discovered information, leading to improved care. That has not been the case in the controversy over labor management. No innovative, highly refined, and generalizable database materialized. Instead, a statistical technique has been used to create CPGs for labor management that have the potential to alter the management of labor around the world. Over the past decade since issued, neither the Zhang methodology nor the CPGs that were formulated based on it have been subjected to any consequential randomly controlled trial to indicate that they are capable of consistently achieving their stated objective of reducing the high cesarean delivery rate whereas at the same time avoiding harm to the mother and fetus. Quite the contrary, a number of studies have been published to show either no significant fall in the frequency of cesarean deliveries or increased adverse maternal and fetal complications, or both.7Rosenbloom J.I. Stout M.J. Tuuli M.G. et al.New labor management guidelines and changes in cesarean delivery patterns.Am J Obstet Gynecol. 2017; 217: 689.e1-689.e8Google Scholar, 8Chaillet N. Dumont A. Abrahamowicz M. et al.A cluster-randomized trial to reduce cesarean delivery rates in Quebec.N Engl J Med. 2015; 372: 1710-1721Google Scholar, 9Neal J.L. Lowe N.K. Phillippi J.C. Carlson N.S. Knupp A.M. Dietrich M.S. Likelihood of cesarean birth among parous women after applying leading active labor diagnostic guidelines.Midwifery. 2018; 67: 64-69Google Scholar, 10Bernitz S. Dalbye R. Zhang J. et al.The frequency of intrapartum caesarean section use with the WHO partograph versus Zhang's guideline in the Labour Progression Study (LaPS): a multicentre, cluster-randomised controlled trial.Lancet. 2019; 26: 340-348Google Scholar, 11Thuillier C. Roy S. Peyronnet V. Quibel T. Nlandu A. Rozenberg P. Impact of recommended changes in labor management for prevention of the primary cesarean delivery.Am J Obstet Gynecol. 2018; 218: 341.e1-341.e9Google Scholar, 12Zipori Y. Grunwald O. Ginsberg Y. Beloosesky R. Weiner Z. The impact of extending the second stage of labor to prevent primary cesarean delivery on maternal and neonatal outcomes.Am J Obstet Gynecol. 2019; 220: 191.e1-191.e7Google Scholar We have argued23Cohen W.R. Friedman E.A. Perils of the new labor management guidelines.Am J Obstet Gynecol. 2015; 212: 420-427Google Scholar, 24Cohen W.R. Friedman E.A. Misguided guidelines for managing labor.Am J Obstet Gynecol. 2015; 212: 753.e1-753.e3Google Scholar, 25Cohen W.R. Sumersille M. Friedman E.A. Management of labor: are the new guidelines justified?.J Midwifery Womens Health. 2018; 63: 10-13Google Scholar, 26Cohen W.R. Friedman E.A. The assessment of labor: a brief history.J Perinat Med. 2018; 46: 1-8Google Scholar, 27Cohen W.R. Friedman E.A. Obstetric practice guidelines: labor's love lost.J Matern Fetal Neonatal Med. 2019; 32: 1567-1570Google Scholar, 28Cohen W.R. Friedman E.A. Guidelines for labor assessment: failure to progress?.Am J Obstet Gynecol. 2020; 222: 342.e1-342.e4Google Scholar that this untested approach could reshape the dilatation curves that describe labor progress, yielding new and possibly misleading rules for labor management and diagnostic conclusions about whether a given labor is normal. Zhang et al's approach (including its potentially error-prone29Varian H.R. Goodness-of-fit in optimizing models.J Econ. 1990; 46: 125-140Google Scholar, 30Gelman A. Imbens G. Why high-order polynomials should not be used in regression discontinuity designs.https://www.nber.org/system/files/working_papers/w20405/w20405.pdfDate: 2014Date accessed: January 17, 2021Google Scholar, 31Gelman A. Zelizer A. Evidence on the deleterious impact of sustained use of polynomial regression on causal inference.Res Polit. 2015; 2: 1-7Google Scholar interval-censored data, interval-censored regression, and high-order polynomial curve fitting) was swiftly accepted as the new benchmark for the analysis of labor progress. This occurred without confirmation by an objective study to ensure it was superior or even equivalent to more traditional approaches or even practical for clinical purposes. We pointed out previously23Cohen W.R. Friedman E.A. Perils of the new labor management guidelines.Am J Obstet Gynecol. 2015; 212: 420-427Google Scholar, 24Cohen W.R. Friedman E.A. Misguided guidelines for managing labor.Am J Obstet Gynecol. 2015; 212: 753.e1-753.e3Google Scholar, 25Cohen W.R. Sumersille M. Friedman E.A. Management of labor: are the new guidelines justified?.J Midwifery Womens Health. 2018; 63: 10-13Google Scholar, 26Cohen W.R. Friedman E.A. The assessment of labor: a brief history.J Perinat Med. 2018; 46: 1-8Google Scholar, 27Cohen W.R. Friedman E.A. Obstetric practice guidelines: labor's love lost.J Matern Fetal Neonatal Med. 2019; 32: 1567-1570Google Scholar, 28Cohen W.R. Friedman E.A. Guidelines for labor assessment: failure to progress?.Am J Obstet Gynecol. 2020; 222: 342.e1-342.e4Google Scholar that although the new guidelines might lead to, at best, a modest reduction in the cesarean delivery rate (because so few cases of misdiagnosed labor aberration fall into the latent phase), any benefit might well be achieved at the cost of untoward maternal and neonatal outcomes (because truly abnormal labors occurring at <6 cm are now considered normal).7Rosenbloom J.I. Stout M.J. Tuuli M.G. et al.New labor management guidelines and changes in cesarean delivery patterns.Am J Obstet Gynecol. 2017; 217: 689.e1-689.e8Google Scholar, 8Chaillet N. Dumont A. Abrahamowicz M. et al.A cluster-randomized trial to reduce cesarean delivery rates in Quebec.N Engl J Med. 2015; 372: 1710-1721Google Scholar, 9Neal J.L. Lowe N.K. Phillippi J.C. Carlson N.S. Knupp A.M. Dietrich M.S. Likelihood of cesarean birth among parous women after applying leading active labor diagnostic guidelines.Midwifery. 2018; 67: 64-69Google Scholar, 10Bernitz S. Dalbye R. Zhang J. et al.The frequency of intrapartum caesarean section use with the WHO partograph versus Zhang's guideline in the Labour Progression Study (LaPS): a multicentre, cluster-randomised controlled trial.Lancet. 2019; 26: 340-348Google Scholar, 11Thuillier C. Roy S. Peyronnet V. Quibel T. Nlandu A. Rozenberg P. Impact of recommended changes in labor management for prevention of the primary cesarean delivery.Am J Obstet Gynecol. 2018; 218: 341.e1-341.e9Google Scholar, 12Zipori Y. Grunwald O. Ginsberg Y. Beloosesky R. Weiner Z. The impact of extending the second stage of labor to prevent primary cesarean delivery on maternal and neonatal outcomes.Am J Obstet Gynecol. 2019; 220: 191.e1-191.e7Google Scholar Our skepticism about the new approach has recently been validated by an important study by De Vries et al.32De Vries B.S. McDonald S. Joseph F.A. et al.Impact of analysis technique on our understanding of the natural history of labour: a simulation study.BJOG. 2021; 128: 1833-1842Google Scholar It helps us to understand what has occurred to alter labor management by introducing new CPGs based on the work of Zhang et al.14Zhang J. Troendle J.F. Yancey M.K. Reassessing the labor curve in nulliparous women.Am J Obstet Gynecol. 2002; 187: 824-828Google Scholar, 15Vahratian A. Troendle J.F. Siega-Riz A.M. Zhang J. Methodological challenges in studying labour progression in contemporary practice.Paediatr Perinat Epidemiol. 2006; 20: 72-78Google Scholar, 16Zhang J. Troendle J. Mikolajczyk R. Sundaram R. Beaver J. Fraser W. The natural history of the normal first stage of labor.Obstet Gynecol. 2010; 115: 705-710Google Scholar, 17Laughon S.K. Branch D.W. Beaver J. Zhang J. Changes in labor patterns over 50 years.Am J Obstet Gynecol. 2012; 206: 419.e1-419.e9Google Scholar, 18Zhang J. Troendle J. Grantz K.L. Reddy U.M. Statistical aspects of modeling the labor curve.Am J Obstet Gynecol. 2015; 212: 750.e1-750.e4Google Scholar, 19Zhang J. Duan T. The physiologic pattern of normal labour progression.BJOG. 2018; 125: 955Google Scholar De Vries et al32De Vries B.S. McDonald S. Joseph F.A. et al.Impact of analysis technique on our understanding of the natural history of labour: a simulation study.BJOG. 2021; 128: 1833-1842Google Scholar created 2 large databases, each with 500,000 simulated labor curves replicating the populations in the databases used by Friedman33Friedman E.A. Labor: clinical evaluation and management.First ed. Appleton Century Crofts, New York, NY1967Google Scholar,34Friedman E.A. Labor: clinical evaluation and management.Second ed. Appleton Century Crofts, New York, NY1978Google Scholar and by Zhang14Zhang J. Troendle J.F. Yancey M.K. Reassessing the labor curve in nulliparous women.Am J Obstet Gynecol. 2002; 187: 824-828Google Scholar, 15Vahratian A. Troendle J.F. Siega-Riz A.M. Zhang J. Methodological challenges in studying labour progression in contemporary practice.Paediatr Perinat Epidemiol. 2006; 20: 72-78Google Scholar, 16Zhang J. Troendle J. Mikolajczyk R. Sundaram R. Beaver J. Fraser W. The natural history of the normal first stage of labor.Obstet Gynecol. 2010; 115: 705-710Google Scholar, 17Laughon S.K. Branch D.W. Beaver J. Zhang J. Changes in labor patterns over 50 years.Am J Obstet Gynecol. 2012; 206: 419.e1-419.e9Google Scholar, 18Zhang J. Troendle J. Grantz K.L. Reddy U.M. Statistical aspects of modeling the labor curve.Am J Obstet Gynecol. 2015; 212: 750.e1-750.e4Google Scholar, 19Zhang J. Duan T. The physiologic pattern of normal labour progression.BJOG. 2018; 125: 955Google Scholar, respectively. The value of simulated data studies to assess the worthiness of research data of this kind is well established.35Lindsey J.C. Ryan L.M. Tutorial in biostatistics methods for interval-censored data.Stat Med. 1998; 17: 219-238Google Scholar One group consisted of a broad range of possible dilatation patterns that corresponded to the linear portions of the traditional sigmoid shape, intended to represent the latent and active phases described by Friedman for both observational measurements and computer-designed curves.36Friedman E.A. Kroll B.H. Computer analysis of labour progression.J Obstet Gynaecol Br Commonw. 1969; 76: 1075-1079Google Scholar, 37Friedman E.A. Kroll B.H. Computer analysis of labor progression. II. Distribution of data and limits of normal.J Reprod Med. 1971; 6: 20-25Google Scholar, 38Friedman E.A. Kroll B.H. Computer analysis of labor progression. 3. Pattern variations by parity.J Reprod Med. 1971; 6: 179-183Google Scholar, 39Friedman E.A. Kroll B.H. Computer analysis of labor progression. IV. Diagnosis of secondary arrest of dilatation.J Reprod Med. 1971; 7: 176-178Google Scholar, 40Friedman E.A. Kroll B.H. Computer analysis of labor progression. V. Effects of fetal presentation and position.J Reprod Med. 1972; 8: 117-121Google Scholar The other group of simulated labor curves was based on the spectrum of hyperbolic forms in the database used by Zhang et al.3Afshari A. De Hert S. Pitfalls of clinical practice guidelines in the era of broken science: let's raise the standards.Eur J Anaesthesiol. 2018; 35: 903-906Google Scholar, 4Kung J. Miller R.R. Mackowiak P.A. Failure of clinical practice guidelines to meet Institute of Medicine standards: two more decades of little, if any, progress.Arch Intern Med. 2012; 172: 1628-1633Google Scholar, 5Shaneyfelt T. In guidelines we cannot trust.Arch Intern Med. 2012; 172: 1633-1634Google Scholar, 6Graham R, Mancher M, Wolman DM, Greenfield S, Steinberg E. Clinical practice guidelines we can trust. Institute of Medicine. Washington, DC: National Academies Press; 2011.Google Scholar, 7Rosenbloom J.I. Stout M.J. Tuuli M.G. et al.New labor management guidelines and changes in cesarean delivery patterns.Am J Obstet Gynecol. 2017; 217: 689.e1-689.e8Google Scholar Importantly, because the raw dilatation data were completely known in advance by virtue of the simulation process, De Vries et al32De Vries B.S. McDonald S. Joseph F.A. et al.Impact of analysis technique on our understanding of the natural history of labour: a simulation study.BJOG. 2021; 128: 1833-1842Google Scholar could assess the statistical analytical methods of Zhang et al14Zhang J. Troendle J.F. Yancey M.K. Reassessing the labor curve in nulliparous women.Am J Obstet Gynecol. 2002; 187: 824-828Google Scholar, 15Vahratian A. Troendle J.F. Siega-Riz A.M. Zhang J. Methodological challenges in studying labour progression in contemporary practice.Paediatr Perinat Epidemiol. 2006; 20: 72-78Google Scholar, 16Zhang J. Troendle J. Mikolajczyk R. Sundaram R. Beaver J. Fraser W. The natural history of the normal first stage of labor.Obstet Gynecol. 2010; 115: 705-710Google Scholar, 17Laughon S.K. Branch D.W. Beaver J. Zhang J. Changes in labor patterns over 50 years.Am J Obstet Gynecol. 2012; 206: 419.e1-419.e9Google Scholar, 18Zhang J. Troendle J. Grantz K.L. Reddy U.M. Statistical aspects of modeling the labor curve.Am J Obstet Gynecol. 2015; 212: 750.e1-750.e4Google Scholar, 19Zhang J. Duan T. The physiologic pattern of normal labour progression.BJOG. 2018; 125: 955Google Scholar for their ability to correctly summarize the dilatation pattern for both the simulated modified sigmoid curves and the simulated hyperbolic patterns of labor progression. De Vries et al32De Vries B.S. McDonald S. Joseph F.A. et al.Impact of analysis technique on our understanding of the natural history of labour: a simulation study.BJOG. 2021; 128: 1833-1842Google Scholar tried to replicate both the repeated measures polynomial regression (used to generate a graph of mean cervical dilatation over time) and the interval-censored regression (used to calculate estimates of centimeter-by-centimeter cervical dilatation times) of Zhang et al.14Zhang J. Troendle J.F. Yancey M.K. Reassessing the labor curve in nulliparous women.Am J Obstet Gynecol. 2002; 187: 824-828Google Scholar, 15Vahratian A. Troendle J.F. Siega-Riz A.M. Zhang J. Methodological challenges in studying labour progression in contemporary practice.Paediatr Perinat Epidemiol. 2006; 20: 72-78Google Scholar, 16Zhang J. Troendle J. Mikolajczyk R. Sundaram R. Beaver J. Fraser W. The natural history of the normal first stage of labor.Obstet Gynecol. 2010; 115: 705-710Google Scholar, 17Laughon S.K. Branch D.W. Beaver J. Zhang J. Changes in labor patterns over 50 years.Am J Obstet Gynecol. 2012; 206: 419.e1-419.e9Google Scholar, 18Zhang J. Troendle J. Grantz K.L. Reddy U.M. Statistical aspects of modeling the labor curve.Am J Obstet Gynecol. 2015; 212: 750.e1-750.e4Google Scholar, 19Zhang J. Duan T. The physiologic pattern of normal labour progression.BJOG. 2018; 125: 955Google Scholar When De Vries et al32De Vries B.S. McDonald S. Joseph F.A. et al.Impact of analysis technique on our understanding of the natural history of labour: a simulation study.BJOG. 2021; 128: 1833-1842Google Scholar Subjected their simulated modified sigmoid labor patterns to the Zhang method, all the curves were converted to hyperbolas and the durations of their nonlinear latent and active phases were markedly prolonged. Furthermore, when the Zhang approach was applied to the simulated hyperbolic curves, the results deviated even more from the underlying "true" data. In other words, using Zhang et al's mathematical approach to curve fitting led to changes that would likely alter both the understanding of the physiological labor process and the clinical decision-making regarding labor management by virtue of their marked deviations, in time and pattern, from traditional concepts of the progress of dilatation in labor. Among other important specific issues related to the Zhang methods, De Vries et al32De Vries B.S. McDonald S. Joseph F.A. et al.Impact of analysis technique on our understanding of the natural history of labour: a simulation study.BJOG. 2021; 128: 1833-1842Google Scholar found that they were unable to detect the expected change from the slow latent phase to the rapid acceleration that was represented in the simulated Friedman curves; they overestimated the lengths of the component parts of the labor curve, especially at small cervical dilatations. The dilatation rates from 4 cm to 5 cm and from 5 cm to 6 cm were prolonged, and the traverse times were also longer when examination intervals were >0.5 to 1.5 hours apart. Zhang et al14Zhang J. Troendle J.F. Yancey M.K. Reassessing the labor curve in nulliparous women.Am J Obstet Gynecol. 2002; 187: 824-828Google Scholar, 15Vahratian A. Troendle J.F. Siega-Riz A.M. Zhang J. Methodological challenges in studying labour progression in contemporary practice.Paediatr Perinat Epidemiol. 2006; 20: 72-78Google Scholar, 16Zhang J. Troendle J. Mikolajczyk R. Sundaram R. Beaver J. Fraser W. The natural history of the normal first stage of labor.Obstet Gynecol. 2010; 115: 705-710Google Scholar, 17Laughon S.K. Branch D.W. Beaver J. Zhang J. Changes in labor patterns over 50 years.Am J Obstet Gynecol. 2012; 206: 419.e1-419.e9Google Scholar, 18Zhang J. Troendle J. Grantz K.L. Reddy U.M. Statistical aspects of modeling the labor curve.Am J Obstet Gynecol. 2015; 212: 750.e1-750.e4Google Scholar, 19Zhang J. Duan T. The physiologic pattern of normal labour progression.BJOG. 2018; 125: 955Google Scholar acknowledged that they seldom, if ever, encountered database cases in which the frequency of examinations was so close together. This pointed to another issue with the composition of Zhang's database insofar as the methodologic limitations related to case characteristics, particularly because the best approximation of fit for summary dilatation curves in the study by De Vries et al32De Vries B.S. McDonald S. Joseph F.A. et al.Impact of analysis technique on our understanding of the natural history of labour: a simulation study.BJOG. 2021; 128: 1833-1842Google Scholar was found among the very cases not (or seldomly) encountered in Zhang's database. Moreover, the Zhang-analyzed curves were all prolonged relative to the "true" simulated dilatation data. The researchers thus concluded that "repeated-measures polynomial regression and interval-censored41Morris TP, White IR, Crowther MJ. Using simulation studies to evaluate statistical methods. Stat Med 2019;38:2074–2102.Google Scholar regression should not be routinely used to define labour progress because they do not accurately reflect the underlying data." The results of this investigation32De Vries B.S. McDonald S. Joseph F.A. et al.Impact of analysis technique on our understanding of the natural history of labour: a simulation study.BJOG. 2021; 128: 1833-1842Google Scholar serve to question the validity of the Zhang et al14Zhang J. Troendle J.F. Yancey M.K. Reassessing the labor curve in nulliparous women.Am J Obstet Gynecol. 2002; 187: 824-828Google Scholar, 15Vahratian A. Troendle J.F. Siega-Riz A.M. Zhang J. Methodological challenges in studying labour progression in contemporary practice.Paediatr Perinat Epidemiol. 2006; 20: 72-78Google Scholar, 16Zhang J. Troendle J. Mikolajczyk R. Sundaram R. Beaver J. Fraser W. The natural history of the normal first stage of labor.Obstet Gynecol. 2010; 115: 705-710Google Scholar, 17Laughon S.K. Branch D.W. Beaver J. Zhang J. Changes in labor patterns over 50 years.Am J Obstet Gynecol. 2012; 206: 419.e1-419.e9Google Scholar, 18Zhang J. Troendle J. Grantz K.L. Reddy U.M. Statistical aspects of modeling the labor curve.Am J Obstet Gynecol. 2015; 212: 750.e1-750.e4Google Scholar, 19Zhang J. Duan T. The physiologic pattern of normal labour progression.BJOG. 2018; 125: 955Google Scholar approach and the utility of the ACOG/SMFM guidelines, which were grounded principally on Zhang's methodology. These recent disclosures about the Zhang model should give us pause. In addition to the concerns about curve fitting, we have previously pointed out the biases that may have been introduced into the new guidelines by issues related to case selection and discounting of potentially important confounders.23Cohen W.R. Friedman E.A. Perils of the new labor management guidelines.Am J Obstet Gynecol. 2015; 212: 420-427Google Scholar, 24Cohen W.R. Friedman E.A. Misguided guidelines for managing labor.Am J Obstet Gynecol. 2015; 212: 753.e1-753.e3Google Scholar, 25Cohen W.R. Sumersille M. Friedman E.A. Management of labor: are the new guidelines justified?.J Midwifery Womens Health. 2018; 63: 10-13Google Scholar, 26Cohen W.R. Friedman E.A. The assessment of labor: a brief history.J Perinat Med. 2018; 46: 1-8Google Scholar, 27Cohen W.R. Friedman E.A. Obstetric practice guidelines: labor's love lost.J Matern Fetal Neonatal Med. 2019; 32: 1567-1570Google Scholar, 28Cohen W.R. Friedman E.A. Guidelines for labor assessment: failure to progress?.Am J Obstet Gynecol. 2020; 222: 342.e1-342.e4Google Scholar When considered in concert with a number of comparative studies that showed little or no evident benefit associated with the new guidelines (other than a small, but inconsistent, fall in the cesarean delivery rate) and that, at the same time, suggested they are accompanied by risk accrual,7Rosenbloom J.I. Stout M.J. Tuuli M.G. et al.New labor management guidelines and changes in cesarean delivery patterns.Am J Obstet Gynecol. 2017; 217: 689.e1-689.e8Google Scholar, 8Chaillet N. Dumont A. Abrahamowicz M. et al.A cluster-randomized trial to reduce cesarean delivery rates in Quebec.N Engl J Med. 2015; 372: 1710-1721Google Scholar, 9Neal J.L. Lowe N.K. Phillippi J.C. Carlson N.S. Knupp A.M. Dietrich M.S. Likelihood of cesarean birth among parous women after applying leading active labor diagnostic guidelines.Midwifery. 2018; 67: 64-69Google Scholar, 10Bernitz S. Dalbye R. Zhang J. et al.The frequency of intrapartum caesarean section use with the WHO partograph versus Zhang's guideline in the Labour Progression Study (LaPS): a multicentre, cluster-randomised controlled trial.Lancet. 2019; 26: 340-348Google Scholar, 11Thuillier C. Roy S. Peyronnet V. Quibel T. Nlandu A. Rozenberg P. Impact of recommended changes in labor management for prevention of the primary cesarean delivery.Am J Obstet Gynecol. 2018; 218: 341.e1-341.e9Google Scholar, 12Zipori Y. Grunwald O. Ginsberg Y. Beloosesky R. Weiner Z. The impact of extending the second stage of labor to prevent primary cesarean delivery on maternal and neonatal outcomes.Am J Obstet Gynecol. 2019; 220: 191.e1-191.e7Google Scholar it is difficult to defend their use. The new guidelines thus do not seem to have advanced our understanding of how labor progresses or how best to manage labor safely. It is highly unlikely that the fundamental nature of human labor has changed substantially over the last 60+ years, an infinitesimal moment in evolutionary terms. Although the basic pattern of labor progression has undoubtedly remained the same, one cannot deny the possibility that it may have changed somewhat in response to altered demographic characteristics of mothers and fetuses, such as more frequent obesity, older age and diabetes in mothers, and macrosomia in fetuses. Yet, a new analytical approach had many convinced that the physiological process of labor had indeed changed or, worse, that we had been wrong about it all along. The admonitions against accepting medical practice innovations without proper pre- and post-testing and objective verification of their underlying premises seem to have been ignored. We have been advised to accept a hyperbolic course of dilatation devoid of variable inflection points to accurately mark the transition of any given labor from latent phase into active phase labor. We have been assigned 6 cm or more as the fixed transition point at (or after) which all labors should be expected to enter the active phase, in contradistinction to the variable inflections found heretofore among all labors plotted on the basis of sequential cervical examinations.33Friedman E.A. Labor: clinical evaluation and management.First ed. Appleton Century Crofts, New York, NY1967Google Scholar,34Friedman E.A. Labor: clinical evaluation and management.Second ed. Appleton Century Crofts, New York, NY1978Google Scholar At the same time, we have been told that labor patterns previously considered abnormal before 6 cm dilatation are probably normal. And we have modified clinical management guidelines on the basis of these claims. It is quite probable that there are more dysfunctional labor patterns observed today mainly because of the changed population characteristics listed earlier. We agree with the ACOG/SMFM guidelines that some of the diagnoses of arrested or protracted active-phase labors, particularly those seeming to occur in the latent phase of labor, are not justified. But creating a fixed dilatation level of 6 cm or more for transition from latent phase to active phase, according to the CPGs for labor management, mislabels many parturients who are already in the active phase well before 6 cm is reached as still being in the latent phase. Even Zhang et al14Zhang J. Troendle J.F. Yancey M.K. Reassessing the labor curve in nulliparous women.Am J Obstet Gynecol. 2002; 187: 824-828Google Scholar, 15Vahratian A. Troendle J.F. Siega-Riz A.M. Zhang J. Methodological challenges in studying labour progression in contemporary practice.Paediatr Perinat Epidemiol. 2006; 20: 72-78Google Scholar, 16Zhang J. Troendle J. Mikolajczyk R. Sundaram R. Beaver J. Fraser W. The natural history of the normal first stage of labor.Obstet Gynecol. 2010; 115: 705-710Google Scholar, 17Laughon S.K. Branch D.W. Beaver J. Zhang J. Changes in labor patterns over 50 years.Am J Obstet Gynecol. 2012; 206: 419.e1-419.e9Google Scholar, 18Zhang J. Troendle J. Grantz K.L. Reddy U.M. Statistical aspects of modeling the labor curve.Am J Obstet Gynecol. 2015; 212: 750.e1-750.e4Google Scholar, 19Zhang J. Duan T. The physiologic pattern of normal labour progression.BJOG. 2018; 125: 955Google Scholar acknowledged this to be true. According to this directive, a finite proportion of such mothers and babies are exposed to risk by preventing clinicians from recognizing a potentially serious disorder of labor. Suppressing this information means they are unable to act expeditiously to assess and to aggressively intervene when there is ample cause for them to do so. The ability to recognize patterns of real abnormal labor and to respond to them appropriately has not been enhanced by adoption of the new guidelines for labor assessment. Arguably, that critically needed identification and intervention, if called for, have instead been hampered. There are lessons to be drawn from these recent experiences and revelations. The Cold War's oxymoronic admonition to "trust but verify" comes to mind. The clinical guidelines for labor management did not sufficiently document that every one of the important Institute of Medicine's rules for producing trustworthy guidelines were followed, including the importance of ensuring against bias.6Graham R, Mancher M, Wolman DM, Greenfield S, Steinberg E. Clinical practice guidelines we can trust. Institute of Medicine. Washington, DC: National Academies Press; 2011.Google Scholar Verification takes time and clear-sighted, knowledgeable probing. We have to ask, what was the hurry? If serious about practicing evidence-based medicine, the panel that authored the guidelines should have delved into whether there was a problem with the structure and content of the evidence that served to support the guidelines and with the database and the analytical issues that have been raised. We recognize that the urgency to drastically overhaul long-standing traditional guidelines for labor management arose primarily from concerns about the rising cesarean delivery rate. But the cesarean delivery rate, as we have previously emphasized,24Cohen W.R. Friedman E.A. Misguided guidelines for managing labor.Am J Obstet Gynecol. 2015; 212: 753.e1-753.e3Google Scholar is merely a symptom and not the root problem that we feel must be corrected. There are many factors that have contributed to the rising rate. We are persuaded, for example, that a major one has to do with the manifestly disconcerting atrophy of fundamental clinical skills among trainees and practitioners. The wherewithal exists to practice obstetrics with a moderate-to-low cesarean delivery rate while maximizing good outcomes.25Cohen W.R. Sumersille M. Friedman E.A. Management of labor: are the new guidelines justified?.J Midwifery Womens Health. 2018; 63: 10-13Google Scholar, 26Cohen W.R. Friedman E.A. The assessment of labor: a brief history.J Perinat Med. 2018; 46: 1-8Google Scholar, 27Cohen W.R. Friedman E.A. Obstetric practice guidelines: labor's love lost.J Matern Fetal Neonatal Med. 2019; 32: 1567-1570Google Scholar As a specialty, we should focus on using those tools skillfully and teaching them respectfully before leaning on untested guidelines based on uncertain evidence. That is not a recipe for optimizing care for pregnant women and their offspring. They deserve better. We acknowledge with sincere thanks the valuable contribution by Bradley S. De Vries, BSc(Med), PhD, who graciously helped to clarify details related to his group's report on their investigation.

During labor mother and fetus are evaluated at intervals to assess their well-being and determine how the labor is progressing. These assessments require skillful physical diagnosis and the ability to translate the acquired information into meaningful prognostic decision-making. We describe a coordinated approach to the assessment of labor. Graphing of serial measurements of cervical dilatation and fetal station creates "labor curves," which provide diagnostic and prognostic information. Based on these curves we recognize nine discrete labor abnormalities. Many may be related to insufficient or disordered contractile mechanisms. Several factors are strongly associated with development of labor disorders, including cephalopelvic disproportion, excess analgesia, fetal malpositions, intrauterine infection, and maternal obesity. Clinical cephalopelvimetry involves assessing pelvic traits and predicting their effects on labor. These observations must be integrated with information derived from the labor curves. Exogenous oxytocin is widely used. It has a high therapeutic index, but is easily misused. Oxytocin treatment should be restricted to situations in which its potential benefits clearly outweigh its risks. This requires there be a documented labor dysfunction or a legitimate medical reason to shorten the labor. Normal labor and delivery pose little risk to a healthy fetus; but dysfunctional labors, especially if stimulated excessively by oxytocin or terminated by complex operative vaginal delivery, have the potential for considerable harm. Conscientiously implemented, the approach to the evaluation of labor outlined in this review will result in a reasonable cesarean rate and minimize risks that may accrue from the labor and delivery process.

Objective: We compared the association between cord arterial catecholamine levels and fetal oxygenation in newborns of mothers with diabetes mellitus to those of nondiabetic pregnancies. Methods: Cord blood obtained at delivery in 25 term appropriate-for-gestational age newborns of women with diabetes and 27 nondiabetic controls were assayed for norepinephrine, epinephrine, insulin, glucose, and blood gases. Results: There was no statistical difference in parity, birth weight, gestational age, delivery mode, use of epidural analgesia, or frequency of low 1-min Apgar scores between the groups. The pO(2) and frequency of cord arterial pH < 7.20 were also similar. Diabetic pregnancies had somewhat higher fetal glucose and substantially higher insulin levels than controls. Regression analysis using cord arterial pH to reflect oxygenation revealed significant inverse relationships between cord artery pH and ln norepinephrine (Prob > F = .001) and ln epinephrine (Prob > F = .019) in controls. In newborns of women with diabetes, however, neither relationship was significant. Conclusion: The expected surge in catecholamines associated with diminished oxygenation was attenuated in fetuses of diabetic mothers. This suggests the possibility that fetal exposure to hyperglycemia or other metabolic derangements in pregnant diabetics might compromise the fetal ability to adapt to changes in oxygenation, and might thereby contribute to the risk of fetal death.

Noninvasive fetal heart rate monitoring using transabdominal fetal electrocardiographic detection is now commercially available and has been demonstrated to be an effective alternative to traditional Doppler ultrasonographic techniques. Our objective in this study was to compare the results of computerized identification of fetal heart rate patterns generated by ultrasound-based and transabdominal fetal electrocardiogram-based techniques with simultaneously obtained fetal scalp electrode-derived heart rate information . We applied an objective computer-based analysis for recognition of fetal heart rate patterns (Monica Decision Support) to data obtained simultaneously from a direct fetal scalp electrode, Doppler ultrasound, and the abdominal-fetal electrocardiogram techniques. This allowed us to compare over 145 hours of fetal heart rate patterns generated by the external devices with those derived from the scalp electrode in 30 term singleton uncomplicated pregnancies during labor. The direct fetal scalp electrode is considered to be the most accurate and reliable technique used in current clinical practice, and was, therefore, used as the standard for comparison. The program quantified the baseline heart rate, long- and short-term variability. It indicated when an acceleration or deceleration was present and whether it was large or small. Ultrasound was associated with significantly greater deviations from the fetal scalp electrode results than the abdominal fetal electrocardiogram technique in recognizing the correct baseline heart rate, its variability, and the presence of small and large accelerations and small decelerations. For large decelerations the two external methods were each not significantly different from the scalp electrode results. Noninvasive fetal heart rate monitoring using maternal abdominal wall electrodes to detect fetal cardiac activity more reliably reproduced the computerized analysis of heart rate patterns derived from a direct fetal scalp electrode than did traditional ultrasound-based monitoring. Abdominal-fetal electrocardiogram should, therefore, be considered a primary option for externally monitored patients.

Introduction Noninvasive fetal heart rate monitoring using transabdominal fetal electrocardiographic detection is now commercially available and has been demonstrated to be an effective alternative to traditional Doppler ultrasonographic techniques. Our objective in this study was to compare the results of computerized identification of fetal heart rate patterns generated by ultrasound-based and transabdominal fetal electrocardiogram-based techniques with simultaneously obtained fetal scalp electrode-derived heart rate information. Material and methods We applied an objective computer-based analysis for recognition of fetal heart rate patterns (Monica Decision Support) to data obtained simultaneously from a direct fetal scalp electrode, Doppler ultrasound, and the abdominal-fetal electrocardiogram techniques. This allowed us to compare over 145 hours of fetal heart rate patterns generated by the external devices with those derived from the scalp electrode in 30 term singleton uncomplicated pregnancies during labor. The direct fetal scalp electrode is considered to be the most accurate and reliable technique used in current clinical practice, and was, therefore, used as the standard for comparison. The program quantified the baseline heart rate, long- and short-term variability. It indicated when an acceleration or deceleration was present and whether it was large or small. Results Ultrasound was associated with significantly greater deviations from the fetal scalp electrode results than the abdominal fetal electrocardiogram technique in recognizing the correct baseline heart rate, its variability, and the presence of small and large accelerations and small decelerations. For large decelerations the two external methods were each not significantly different from the scalp electrode results. Conclusions Noninvasive fetal heart rate monitoring using maternal abdominal wall electrodes to detect fetal cardiac activity more reliably reproduced the computerized analysis of heart rate patterns derived from a direct fetal scalp electrode than did traditional ultrasound-based monitoring. Abdominal-fetal electrocardiogram should, therefore, be considered a primary option for externally monitored patients.

The ongoing debate about what models of cervical dilatation and fetal descent should guide clinical decision-making has sown uncertainty among obstetric practitioners. We previously argued that the adoption of recently published labor assessment guidelines promoted by the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine may have been premature. Before accepting any new clinical approaches as the standard of care, their underlying hypotheses should be thoroughly tested to ensure they are at least equivalent (or, preferably, superior) to existing management paradigms. Some of the apparent urgency to subscribe to new clinical tactics has been fueled by legitimate concerns about the rise in the cesarean delivery rate over the past several decades. A major contributor to this change in practice patterns is that more cesarean deliveries are being done for diagnoses that fall under the rubric of dystocia than ever before. As a consequence, traditional labor curves-fundamental for assessing labor progress-and the practice paradigms associated with them have received intense scrutiny as a possible contributor to this delivery trend. Moreover, the recent proposal of new labor curves and accompanying management guidelines has, understandably, fed the appetite to correct a perceived problem. However, the cesarean delivery rate rose most rapidly during decades when there was no major change in traditional labor curves or in the guidelines for their interpretation. Also, during the years since the new guidelines were first published, there has been no major fall in cesarean delivery frequency. This raises the question of whether there was truly a fundamental flaw in the traditional labor management paradigms or whether their proper interpretation and use had been somehow forgotten, ignored, or corrupted. More important, existing studies have shown that application of the new guidelines often (but not always) results in a modest fall in the cesarean delivery rate, but that this change may be accompanied by significant increases in maternal and neonatal morbidity. These results strongly suggest more caution in the adoption of the American College of Obstetricians and Gynecologists / Society for Maternal-Fetal Medicine labor assessment recommendations. They are based on a hypothesis that has yet to undergo thorough evaluation of its risks and benefits.

Objective The objective of this study was to compare performance of a maternal surface electrode patch with ultrasound- and tocodynamometer-based monitoring to detect fetal heart rate and uterine contractility in late preterm labors. Study Design Thirty women between 340/7 and 366/7 weeks' gestation were monitored simultaneously with a Doppler/tocodynamometer system and a wireless fetal–maternal abdominal surface electrode system. Fetal and maternal heart rate and uterine contraction data from both systems were compared. Reliability was measured by the success rate and percent agreement. Deming regression and Bland–Altman analysis estimated the concordance between the systems. Uterine contractions were assessed by visual interpretation of monitor tracings. Results The success rate for the surface electrode system was 89.5% (95% confidence interval [CI], 85.7–93.3), and for ultrasound it was 88.4% (95% CI, 84.9–91.9; p = 0.73), with a percent agreement of 88.1% (95% CI, 84.2–92.8). Results were uninfluenced by the patients' body mass. The mean Deming slope was 1 and the y-intercept was −3.0 beats per minute (bpm). Bland–Altman plots also showed a close relationship between the methods, with limits of agreement less than 10 bpm. The percent agreement for maternal heart rate was 98.2% (95% CI, 97.4–98.8), and for uterine contraction detection it was 89.5% (95% CI, 85.5–93.4). Conclusion Fetal heart rate and uterine contraction monitoring at 340/7 to 366/7 weeks using abdominal surface electrodes was not inferior to Doppler ultrasound/tocodynamometry for fetal–maternal assessment. Registration clinicaltrials.gov/February 20, 2017/identifier NCT03057275. Key Points

Objective: This clinical perspective reviews the causes, prevention and treatment of accidental hypothermia in severe obstetric hemorrhage. Results: Hypothermia commonly accompanies hemorrhagic shock. Hypothermia can inhibit blood coagulation, reduce cardiac contractility, predispose to arrhythmias, contribute to acidosis, and suppress immune function. Several techniques for warming a patient or reducing heat loss are available. Keeping the patient dry, covering her with blankets, and raising the ambient temperature in the room are valuable. Methods to transmit heat actively are more effective. Forced warm air blowers are efficient. Heating intravenous fluids is important, and warm fluid lavage of the open abdomen can be effective. Conclusion: Monitoring core temperature in the operating room and choosing therapy is a shared responsibility of surgeon and anesthesiologist.