Epidemiologic Data

During the 1970's, the cesarean birth rate in the United States increased about threefold, from 5.5 percent in 1970 to 15.2 percent in 1978, and appears to be continuing to increase. This trend is pervasive, affecting hospitals and patients in all parts of the country.

An increase in cesarean rates is also evident internationally. The Canadian rate has most closely paralleled that of the United States, moving from 7.5 percent in 1972-1973 to 13.9 percent in 1979. In western European nations, cesarean delivery rates are considerably lower than in Canada and the U.S.; however, a trend toward an increase in cesarean delivery is reported in France, England, Norway, and The Netherlands. Other than the increase in Norway between 1975 and 1978, the U.S. has experienced the sharpest increase.

Concurrent with the rise in cesarean delivery rates is an international trend toward greater reliance on medical specialists for management of childbirth. This includes more deliveries performed by obstetricians as compared with general practitioners or midwives and better access to a full complement of hospital resources.

In the United States, the diagnostic categories having the largest effect on the increase in the cesarean birth rate between 1970 and 1978 are:

The cesarean birth experience in New York City, an area for which data from birth and death certificates are available to assess changes in methods of delivery from 1968-1977, is consistent with the national data. In addition, along with the rise in cesarean births, there is a trend away from forceps delivery.

Low birth weight is associated with relatively high rates for primary cesarean birth. However, because more than 90 percent of all infants weigh over 2500 grams at birth, the normal birth weight group makes the largest contribution to the number of cesarean births.

The rate of increase in primary cesarean birth in New York City over the decade was similar at almost all birth weights. The incidence of low birth weight decreased both overall and among cesarean births. These changes in incidence of low birth weight run counter to the upward trend in cesarean birth rates.

Neonatal mortality decreased markedly in New York City between 1967-68 and 1976-77. The largest decrease occurred in the group of infants weighing 1000-2500 grams. In this group, both primary cesarean and vaginal births had large decreases in neonatal mortality. These decreases may have been influenced by concomitant improvements in factors such as neonatal intensive care. In births above 2500 grams there was a small decrease in neonatal mortality. No decrease is found in neonatal mortality among all primary cesarean births when allowing for shifts that may have occurred from forceps to cesarean delivery.

Dystocia

The term dystocia encompasses two systems of classification of abnormal labor. The first relates to problems of fetal position or size. The second is less well-defined and includes functional classification of labor with a fetus in the vertex position. The largest contribution (30 percent) to the overall rise in the cesarean delivery rate from 1970 to 1978 came from the diagnostic category of dystocia. Almost all of this contribution is accounted for by the increased frequency of the diagnosis of dystocia. In the New York City data, the diagnosis of dystocia is concentrated among infants with birth weights over 2500 grams, and cesarean delivery is not associated with survival advantage in this group when compared with vaginal births. Adequate data relating to infant morbidity, and specifically abnormal neurologic development, in association with dystocia are unavailable.

Problems of fetal position and size (fetopelvic disproportion) are generally easily recognized; appropriate guidelines for obstetrical conduct in these situations are available; and fetal and maternal outcome effects are reasonably well known. These problems, excluding the breech birth, which is discussed as a separate category, are not a major reason for the increase in cesarean birth rates in the dystocia category.

The functional classification of labor as dystocia with a fetus in vertex presentation is more complex. The ability of the fetus weighing less than 1000 grams to tolerate vaginal or cesarean birth has not been adequately evaluated. Similarly, the fetus weighing more than 4000 grams, when recognized, requires particularly cautious obstetrical management of labor. The remainder of vertex births (over 90 percent) are of normal size fetuses.

Recommendations

1. In the absence of fetal distress, management of dysfunctional labor may include such measures as patient rest, hydration, ambulation, sedation, and use of oxytocin, prior to considering cesarean birth.
2. There is a compelling reason to examine the diagnostic category of dystocia because of its prominent association with the increase in primary cesarean birth rate and the absence of a survival advantage for the cesarean births over 2500 grams.
3. Included among approaches to the issue of dystocia should be (1) peer review within hospitals, (2) examination of the efficacy of methods for assessing the progress of labor, with specific attention to infant and maternal mortality and morbidity, and (3) research clarifying the factors which affect the progress of labor including the effects of emotional support, ambulation, rest, sedation, and oxytocin stimulation.

Repeat Cesarean Delivery

Prior cesarean delivery is one of the two major reasons cited for cesarean birth at this time, and is likely to increase further if present trends continue. This diagnostic category accounted for 25 to 30 percent of the increase in cesarean rate from 1970 to 1978.

Following a cesarean delivery, more than 98 percent of women in the United States undergo a repeat cesarean for any subsequent pregnancy. This practice began in the early 1900's to avoid the risk of uterine rupture at the scar site during labor. At that time the "classical" cesarean incision (a vertical incision in the body of the uterus) predominated, and the cesarean birth rate was extremely low. The incidence of scar rupture is higher in the classical, low vertical, and the inverted T incisions, compared with the low segment transverse incision. Following an initial cesarean birth and during subsequent pregnancies and labors, the low segment transverse uterine incision now in general use is associated with lower maternal and fetal morbidity and mortality. With any uterine scar, however, rupture is unpredictable.

Based on maternal and neonatal mortality rates, the practice of routine repeat cesarean birth is open to question. Repeat cesarean carries two times the risk for maternal mortality of vaginal delivery, and the maternal mortality rate for repeat cesarean has not fallen since 1970. At birth weights below 2501 grams, the New York City data show a consistent neonatal mortality disadvantage for cesarean as compared with vaginal births; at birth weights above 2500 grams, cesarean deliveries have the same mortality rates as vaginal births. Data from national and international sources suggest that labor and vaginal delivery after a previous low segment transverse cesarean birth is of low risk to mother and fetus in properly selected cases.

Recommendations

1. In hospitals with appropriate facilities, services, and staff for prompt emergency cesarean birth, a proper selection of cases should permit a safe trial of labor and vaginal delivery for women who have had a previous low segment transverse cesarean birth. Informed consent should be obtained before a trial of labor is attempted.
2. No changes in present practices are recommended for the delivery by elective repeat cesarean of patients who have had a previous classical, inverted T, or low vertical incision, or for whom there is no documentation of the site and type of the previous cesarean incision.
3. In hospitals without appropriate facilities, services, and staff, the risk of a trial of labor in women who have had a previous cesarean may exceed the risk for both mother and infant from a properly timed, elective repeat cesarean birth. Patients should be informed in advance of the limits of a particular institution's capabilities and of the availability of other institutions capable of offering this service, so that they may make a choice.
4. More adequate information is needed on risks and benefits in trials of labor for patients with previous low segment transverse uterine incisions. Studies designed to provide this information must be of sufficient sample size and include morbidity and mortality information on both mother and infant.
5. Institutions offering trials of labor following a low segment transverse cesarean birth should develop guidelines for the management of those labors.
6. Patient education relating to cesarean birth and repeat cesarean birth should continue throughout pregnancy as an important part of patient participation in decisions concerning anesthesia, elective repeat cesarean birth, or trial of labor following previous cesarean birth.

Breech Presentation

Breech presentation is associated with an increase in both morbidity and mortality when compared with vertex presentation, irrespective of whether delivery is vaginal or cesarean. There is a continuing trend toward delivery of infants in breech presentation by cesarean. Nationally the proportion of breech presentations delivered by cesarean rose from 11.6 percent in 1970 to 60.1 percent in 1978, accounting for about 10-15 percent of the rise in cesarean rate during those years.

In the New York City data, among breech presentations, there is no consistent difference in neonatal mortality at low birth weights (2500 grams or less) between primary cesarean births and vaginal breech deliveries. But, at mature birth weights, breech-presenting infants delivered by cesarean have a fivefold better neonatal mortality rate than those delivered vaginally. The strong qualification, however, is that at birth weights above 2500 grams there has been no overall decrease in mortality over a 10-year period for the total group of breech presentations (vaginal and cesarean combined). This seeming contradiction may reflect a shift of the better risk breech births from the vaginal delivery group to the cesarean birth category. Further exploration of the effect of changes in mode of delivery would require information on infant morbidity and development, not now available.

Evaluation of outcome in breech presentation is complicated by problems related to the increased frequency of prematurity in breech presentations, the different types of breech presentation, congenital anomalies associated with breech presentation, and influence of maternal pelvic size and fetal size on ease of vaginal breech delivery. Maternal morbidity following surgery or difficult breech delivery is a consideration in choosing the method of delivery . Most clinical reviews suggest that abdominal breech delivery may be associated with less risk to the premature fetus, but lack of data on infant morbidity prevents a firm conclusion.

The large fetus presenting as breech, the fetus presenting as a complete or footling breech, and the fetus with marked hyperextension of the head presenting as breech, have a better outcome if delivered by cesarean birth.

Recommendations

1. Vaginal delivery of the term breech should remain an acceptable obstetrical choice for delivery when the following conditions are present:

   1. anticipated fetal weight of less than 8 pounds;
   2. normal pelvic dimensions and architecture;
   3. frank breech presentation without a hyperextended head; and
   4. delivery to be conducted by a physician experienced in vaginal breech delivery.
2. Data are insufficient to make a firm recommendation on the preferable method of delivery for the low birth weight (less than 2501 grams) fetus in the breech presentation.
3. More data should be collected to evaluate the best mode of delivery for fetuses in the breech presentation.
4. Because all breech births have inherent risks that are often uncertain and unpredictable, this information should be shared with the family whenever possible as part of the decision-making process.

Fetal Distress

Asphyxia during labor, which may lead to brain damage, is the most dangerous clinical correlate of fetal distress. Fetal distress ranks third in importance, along with breech presentation, in the rise of cesarean birth rates, accounting for about 10 to 15 percent of the increase. While evidence is lacking that the actual incidence of fetal distress has changed, the diagnosis of fetal distress has been made more frequently during the past 10 years. The use of electronic fetal monitoring is associated with an increased frequency of diagnosis of fetal distress. The diagnosis of fetal distress occurs most frequently in fetuses weighing over 2500 grams. Fetal distress cannot be reliably explored within the New York City data for risk of mortality in relation to method of delivery because the actual number of affected infants is small.

Recommendation

Further studies are needed to improve the accuracy of the diagnosis of fetal distress, and to develop new techniques for making the diagnosis. These advances may be expected to improve fetal outcome and to lower cesarean birth rates.

Other Maternal and Fetal Considerations

Because of a need for early delivery, many maternal and fetal medical problems lead to cesarean birth. Examples include maternal diabetes, pregnancy-induced hypertension, and erythroblastosis fetalis. This entire group contributes only a small part of the cesarean birth rate increase.

Recommendation

If vaginal delivery is to be used in this group, an effective method is needed to stimulate preterm labor safely.

Maternal Mortality and Morbidity

Although overall maternal mortality is extremely uncommon (9.9 deaths/100,000 births in 1978), cesarean birth carries two to four times the risk for mortality when compared with vaginal delivery. Some maternal mortality following cesarean birth is related to maternal illness rather than to the surgery. Maternal mortality rates are still underreported.

Cesarean birth is a major surgical procedure with morbidity greater than vaginal delivery. Infections constitute the greatest portion of this morbidity. The most common infections are endometritis and urinary tract and wound infections. The morbidity may reflect the demographic features of the population cared for, as well as the events of labor and birth.

Recommendations

1. Better data collection is needed to identify the reasons for operative and non-operative maternal deaths.
2. The National Center for Health Statistics should consider revising (1) the standard certificates of birth and fetal death to include items that distinguish between cesarean and vaginal delivery, and (2) the standard certificates of death to include or modify items that improve the identification of maternal deaths. State Health Departments should adopt similar revisions in certificates of birth and death, and a uniform definition of maternal death.
3. For statistical analysis, maternal death certificates should be matched with the corresponding birth and fetal death certificates.
4. Comprehensive studies of morbidity studies with respect to cesarean births, vaginal births and forceps births are needed.
5. Delivery of medical care to patients undergoing cesarean birth should be made equal to that available to general surgical patients.

Anesthesia

Obstetric anesthesia is unique in that it requires attention to the health of at least two patients. Maternal deaths, related to anesthesia, although infrequent, continue to occur. Most anesthesia-related deaths are potentially avoidable. Appropriate anesthetic selection and technique can minimize the inherent medical risks, including the risk of maternal death. There is considerable variation and room for improvement in the number, quality, and availability of obstetric anesthesia services throughout the United States.

Recommendations

1. Choices for the kind of anesthesia should be available and discussed among patient, obstetrician, and anesthesiologist. In particular, where not medically contraindicated, the patient should have the option of receiving regional anesthesia.
2. More comprehensive and continuing data collection is needed to determine the training, availability, and quality of anesthesia support systems and personnel for the obstetric patient.
3. Further study of the effects of obstetric anesthesia on maternal mortality and morbidity and the physiology and conduct of labor is required.
4. The short and long term effects of anesthetic drugs and techniques on the neurobehavioral development of the newborn are poorly described in the existing literature. Understanding these effects is critical to an evaluation of benefits and risks to infant development, and they warrant further study.

Neonatal Respiratory Distress Syndrome

Cesarean birth, particularly in the absence of labor, appears to be associated with an increase in neonatal respiratory distress at all gestational ages. Iatrogenic neonatal respiratory distress due to premature termination of pregnancy should be avoidable by appropriate antenatal use of clinical, biophysical, and biochemical estimators of gestational age. Among fetuses with lungs previously demonstrated as mature, postnatal respiratory distress is unlikely to be a problem, whatever the route chosen for their delivery.

Recommendations

1. Continuing efforts to avoid iatrogenic prematurity are needed. There must be improvement in professional and patient education regarding the necessity for safe and effective antenatal assessment of gestational age and fetal maturity before elective intervention in labor and delivery.
2. Further studies are needed of the influence on neonatal pulmonary function of events surrounding labor and delivery.

Psychological and Developmental Effects

There is limited research concerning the psychological impact on parents following cesarean birth. Nevertheless, surgery is clearly an increased psychological and physical burden when compared with a normal vaginal delivery. In addition, negative responses from mother and father have been reported in the available retrospective studies. In some hospitals, family centered maternity care has been extended to the cesarean birth family, and in these cases there is no evidence of harm to mother, neonate, or father. The presence of fathers in the operating room and closer contact between mother and neonate appear to improve the post-cesarean behavioral responses of the families. One consistent finding from small scale studies of post-cesarean birth families is the greater involvement of fathers with their infants. Improved educational programs for all families so that they may understand the cesarean birth, and specific educational programs for previous cesarean birth families, are methods to improve the birth experience.

Comparative studies of the influence of cesarean birth on infant development often lack a statement on the obstetrical indications for cesarean birth or whether the father was present in the delivery room. Several studies have noted that, although the infant delivered by cesarean has usually received more medication than a control infant delivered vaginally, assessments of neonatal behavior did not reveal depressive effects. Virtually no differences associated with delivery mode have been found in the few reports available on infant development beyond the neonatal period. The published studies in this field are often inadequate in study design and incomplete in infant followup.

Recommendations

1. Parent education during pregnancy by health care providers and in childbirth education classes should include information relating to the possibility of a cesarean birth, an explanation of the technical procedures surrounding the cesarean birth, and discussion of choices available to parents.
2. During labor and at the time a decision to perform a cesarean is made, as time and circumstances permit, a discussion of the indications, procedures, and parental options should take place between the physician or his/her staff and the parents.
3. Information exchange about the entire cesarean birth experience should continue in the postoperative period and at later postpartum visits.
4. In the absence of scientific evidence regarding benefit or risk; the presence at a cesarean birth of the father or surrogate should represent a joint decision among parents, physician, and hospital representatives.
5. Hospitals are encouraged to liberalize their policies concerning the option of having the father or surrogate attend the cesarean birth.
6. The healthy neonate should not be separated routinely from mother and father following delivery.
7. There is a need for longitudinal development followup studies of infants and their parents. These studies should include study populations of sufficient size for meaningful statistical analysis, suitable control groups, and standardized methods of assessment.

Recommendations

1. Although it would be useful to know how the medical benefits of cesarean birth compare with its costs in various situations, until these benefits can be better defined and measured, no recommendation can be made to conduct economic evaluations to address this issue.
2. Research is needed into the nature of economic incentives for and against cesarean birth and into the effect of these incentives on the behavior of physicians and patients.

Legal Concerns

Malpractice suits may be brought against a physician for negligent performance of a cesarean, for not performing a necessary cesarean, or for performing an unnecessary cesarean. Of major concern is the malpractice suit for negligent nonperformance of an allegedly necessary cesarean. The physician defendant is successful in most of these cases. Liability, when found, generally involves gross deviation from the recognized standards of patient care. Appropriate application of the doctrine of informed consent by providing a patient sufficient information to make a knowledgeable treatment choice is protective for the physician. The law also deems the rights of the unborn child worthy of protection. Although commonly cited, there is no evidence that fear of litigation and the possible consequent practice of defensive medicine is a major cause of the increased cesarean birth rate.

Recommendations

1. The courts should recognize that if a vaginal delivery resulted in a "less than perfect" baby, this does not necessarily mean that the physician was negligent for not performing a cesarean birth.
2. Physicians should make a determination as to the need for a cesarean delivery based solely on sound medical judgment.
3. Physicians should support the patient's right to participate in the decision-making process concerning whether to have a cesarean by proper application of the doctrine of informed consent.

Ethical Concerns

The ethical principles associated with cesarean birth are generally not specific to this procedure. They correspond to established patterns governing relationships between health care providers and their patients. They are consistent with providers' traditional commitment to giving patients' interests priority over their own; they acknowledge the right of patients to make informed decisions regarding their own bodies, including the right of proxy consent; they recognize the independent rights of the unborn relative to those of the mother; and they take into account the special needs and concerns of teaching institutions and the ethical difficulties involved in achieving distribution equity in health care.

Recommendation

Further studies are needed to discover whether the increase in cesarean delivery rates in fact represents a violation of any of these general principles.

Research Needs

Throughout this consensus statement, recommendations appear for the development of new data and research studies. The task force has found at all stages of its assessment of problems and issues related to cesarean childbirth that evidence to reach hard conclusions is often not available. In part, it may be due to the complexity of the subject; in part, this may be due to the lag in developing information that identifies the critical questions needing intensive investigations. The epidemiologic analysis of the national and New York City experiences has clarified many of these issues. There is a need for data similar to New York City's for other population groups. However, it is urgent that studies that have the potential for more effectively answering questions concerning the reasons for and efficacy of cesarean birth be conducted. This will require a range of different methodologies, including well designed medical record-based sources of information, interview surveys, case control studies and randomized clinical trials.

Randomized clinical trials are difficult, time-consuming, and expensive. However, in certain circumstances, they offer the only way to address problems definitively. The question of ethics is often raised as an obstacle to the conduct of randomized trials for procedures or managements which are already routine, whether or not they are established. However, failure to conduct feasible randomized trials in the case of clinical practices whose efficacy is not established and is being persuasively challenged, raises ethical issues of greater concern.

Another area of necessary research focus is that of physician practice. The effects of medical training, hospital policy, and ethical and legal concerns on the choice of delivery procedure are currently unexamined subjects deserving greater scrutiny by means of a combination of epidemiological, economic, and social science methods.

Most issues of pivotal importance concerning cesarean birth will require longitudinal infant evaluation. Such studies are expensive and logistically difficult, but they should be regarded by funding agencies as high priority areas.

Major information sources used by the Task Force included a complete bibliography of the world literature since 1966 relating to cesarean births provided by the National Library of Medicine; some yet unpublished studies made specially available; data from government officials and professionals in Canada and Western Europe; national data on cesarean births from the National Center for Health Statistics; information from the Public Health Service, Indian Health Service, and the military services on their cesarean delivery rates; data from the Professional Activity Study of the Commission on Professional and Hospital Activities on the method of delivery employed when various complications of pregnancy were diagnosed in the years 1970, 1974, and 1978; and New York City birth and death record data for the years 1968- 1977. Copies of the full report of the Task Force, containing a description and analysis of the literature and data on which this statement is based, may be obtained from the Office of Research Reporting, NICHD, Building 31, Room 2A34, NIH, 9000 Rockville Pike, Bethesda, Maryland 20205.

Panel of Review

Cesarean childbirth is a medical practice entailing numerous broad social problems and many complex scientific and clinical issues. Accordingly, the sponsor of this conference, the National Institute of Child Health and Human Development (NICHD), established a Task Force of 19 members to gather and analyze data for the Consensus Conference and to produce a draft report with a set of tentative conclusions and recommendations for discussion at a public meeting. This report was widely distributed prior to the consensus meeting. Task Force members were selected to provide expertise and viewpoints from the pertinent medical specialties, as well as from the disciplines of law, ethics, psychology, sociology, and economics and from public interests. Data were gathered from many sources, including various agencies of the Federal government, the New York City government, the Commission of Professional and Hospital Activities, and the governments of Canada, Great Britain, France, and the Netherlands. Based on these data, as well as on information contained in many reports and professional periodicals, the Task Force reached tentative agreement on many of the issues prior to the conference, and subsequently assumed the role of the Consensus Panel for this conference. The role of a Consensus Panel is to reach agreement on a consensus statement that reflects all valid viewpoints presented by participants in the consensus meeting.

While this process is both conceptually sound and consistent with accepted scientific practice, it differed from the process generally used in previous NIH Consensus Development Conferences. The Task Force selected, analyzed, and presented data in its role as a Task Force and then defended the same data, as well as integrated new information in its capacity as a Consensus Panel. Because of the potential for bias on conflicting interest in such an arrangement, the Director, NIH, and the Director, NICHD, impaneled an independent group, the Panel of Review, to evaluate this consensus process and the extent to which the Consensus Statement integrated the viewpoints presented.

The deliberations and findings of this Panel are summarized in this attachment to the Consensus Statement.

This is the first time that such a Panel of Review has been used in a Consensus Development Conference. It appears to have been useful in this particular instance, and might be used again when circumstances indicate the need for an independent assessment of a Consensus Development Conference.

Report of the Panel

The charge to the Panel of Review was set forth by Donald S. Fredrickson, M.D., Director of the National Institutes of Health, and Norman Kretchmer, M.D., Ph.D., Director of the National Institute of Child Health and Human Development, as follows:

The Panel of Review will participate in the Conference by providing an independent view of the process employed and a judgment of the extent to which the consensus statement integrated the data, task force conclusions, and the contributions made by the audience. The Panel of Review will make no recommendations with respect to health care practices.

The Panel of Review received the draft report of the Task Force about a month preceding the meeting, assembled for the first time on September 21, 1980, for discussion of its charge and to develop a general approach to the conference. No members of the Panel of Review had been present at any meeting of the Task Force. The Panel established its own rules of procedures and made its judgments independently.

On September 23, 1980, the Panel of Review met to formulate a report. It has subsequently been modified by comments received by the Chairman from members of the Panel of Review.

Composition of the Task Force

In its charge to prepare a draft report and recommendations on cesarean childbirth, the Task Force had a dual role: to present and analyze the data and to forge a consensus. Each of the two roles is inherently difficult to accomplish. If the two roles had been kept separate, optimal composition of one Task Force would likely have differed from that of the other. For example, in the presentation and analysis of data, stronger representation from health care professionals, epidemiologists, and data experts might have been called for, and credibility strengthened.

The Process

The questions developed by the Task Force were well-framed to permit development of a consensus on the issues of importance to the public. However, the charge to respond to all of these questions may have been overly broad for a single Task Force functioning in this format. As a consequence, conclusions in some instances were limited to those that could be drawn from selected statistical data when other significant information might have contributed to a more complete exposition of the problem. This observation is illustrated by comments from the audience which called attention to the need for consideration and further evaluation of the desire to avoid newborn morbidity and its effect on the rising cesarean birth rate; the overlap between economic, legal, and ethical issues; and the social impact resulting from cesarean childbirth.

As the first step in developing a basis for a consensus statement and as background for the Consensus Development Conference, the Task Force prepared a draft report which was circulated in advance of the conference. Although the report was massive, the Panel of Review has some concern about the way in which data were selected, collected, evaluated, and analyzed.

If a consensus is to be developed, data relevant to all of the issues of concern to all person involved in consensus development need to be included. The judgments used to evaluate validity and reliability of the data (including both original data and that from the literature) need to be stated. The conclusion must be substantiated on the basis of the data presented or if no data are included the reasons for the conclusion must be given and consistent criteria should be used.

Data relevant to many of the issues are not included in the draft; for example, information about public opinion and attitudes, and discussion of controversial issues. Research from behavioral and social sciences might have been amplified. Judgments about the quality of the data which were used or their appropriateness for the project are not presented. Frequently, the basis for a conclusion is not given.

Given the complexity of the problem, the volume of the data, and the diversity of sources, the process of integrating and summarizing the information in written form is recognized as a formidable task. Public comments and discussions among members of the Panel of Review suggest several problems with this aspect of the process. The lack of clear summarizations makes it difficult for the reader to relate the large amount of often conflicting data to the actual conclusions stated at the end of each chapter. Graphic presentation of aggregated data sets and summary recommendations in tabular form would aid in conveying to the public the process of achieving consensus. Such an approach could serve to make explicit the distinction between those situations in which either vaginal or cesarean delivery is clearly superior and those in which such choices cannot be made on the basis of current scientific evidence. Further, the "Summary and Consensus" needs to be more consistent with the individual chapters, integrating and relating the findings in one area with relevant findings in other areas for the preparation of a soundly based consensus statement.

Since the Task Force had already prepared a large report with tentative conclusions and recommendations, the purpose of the meeting was to allow all interested parties to present evidence and opinions. In this way, the Task Force's final report could reflect a general consensus (to the extent that one was found to exist) on the questions the Task Force set out to answer.

To achieve this objective, the Chairman of the Task Force could have presented the summary conclusions on each topic and then solicited the views of the audience, who already had had an opportunity to read the report. Instead, a great deal of time on both days was devoted to oral reiteration of the report, thus greatly reducing the time scheduled for public comment. The actual time was further reduced because the Task Force dominated the discussion; in addition to the principal speaker on each topic, other members also felt obligated to defend their work.

This points to a general impact that the design of this consensus process had on the conduct of the meeting: the Task Force's dual role as both witnesses and judges naturally put them on the defensive. Consequently, the public participants apparently felt the need to be more adversarial in their remarks in trying to have their views taken into account.

The comments of the invited reviewers were generally very helpful in focusing discussion on the salient issues. Unfortunately, the discussion of the economic, ethical, and legal aspects of the subject were relegated to a final few hours of the conference, after the major opportunity for public comments had concluded. This implied (intentionally or not) that these issues are not central to formulating policies on cesarean birth.

Strengths and Weaknesses

The format used to develop a consensus on cesarean childbirth differs in several important respects from most preceding Consensus Development Conferences. In preceding conferences a consensus panel was created to evaluate the evidence presented by the public and by speakers invited to address specific aspects of the problem. In this case, the Task Force that was to arrive at a consensus was created almost a year prior to the Consensus Development Conference to evaluate the information on which the consensus was to be based. It developed a set of preliminary conclusions and drafted a report that presented these conclusions, along with the supporting evidence and rationale. This draft report with its conclusions was then circulated to interested parties and became one of the main focal points of the Consensus Development Conference. Invited reviewers and the public commented on the report as well as presenting their own points of view about the questions being addressed. After discussing the issues raised in the meeting, the Task Force met to assimilate the new information and to arrive at a Consensus Statement. An independent Panel of Review was created to evaluate the process by which a consensus was reached, to help ensure that all the pertinent information and points of view were incorporated in the final consensus.

This format has both strengths and weaknesses. The following are considered to be important strengths:

• By meeting for several months prior to the Consensus Development Conference, the Task Force had the opportunity to synthesize data from many different sources and to perform original analyses. This additional time could potentially improve the quality of information on which the Consensus Statement was based.
• The writing and circulation of the draft report had the potential for making the reasoning of the Task Force explicit, for broadening the access of the public to its deliberations, and for enabling interested parties to review in advance of the Consensus Conference the evidence and rationale for its conclusions.

The format also was felt to have some weaknesses:

• The Task Force was given a dual role; it was put in the position of both providing information and judging that information. This might have biased the process.
• As stated above, the dual function of the Task Force made it difficult to achieve an appropriate composition. Those best qualified to develop and present the information necessary for a consensus may not be best qualified to integrate that information and draw conclusions.
• By submitting a written report with conclusions, the Task Force was put in the awkward position of having to defend its preliminary conclusions. This could inhibit the incorporation of new information and points of view raised by others in the Consensus Development Conference.
• The 2 days allowed for the public to present new information and opinions and to suggest changes in the draft report may have been too short.
• Similarly, it was difficult for the Task Force to assimilate the new information and opinion presented at the conference and reach and write a consensus in 2 days.
• The Panel of Review was charged with reviewing the process by which a consensus was reached, but did not have access to some of the most important deliberations. It could only study the draft report, listen to the comments of the invited reviewers and public, and evaluate the responses of the Task Force members. It could not review the way evidence was collected or analyzed prior to the meeting, or the way the final Consensus Statement was developed.
• The evaluation of the Panel of Review was not available to the Task Force before it had to reach its final consensus.

The Panel of Review believes that it is possible to retain the strengths and correct some of the weaknesses of this format. The following elements might be part of this consensus development process:

• Commissioning a set of papers that address important aspects of the problem;
• Creation of an independent Consensus Development Panel;
• Circulation of the papers well in advance of the consensus meeting to the Consensus Development Panel and to the public;
• Presenting summaries of invited papers at the Consensus Development Conferences; the authors would be available for questioning by both the panelists and the public. The public can contribute additional information and opinions at that time;
• Development and announcement by the Consensus Development Panel of a preliminary consensus statement at the end of the conference;
• Development of a final statement by the Consensus Development Panel in a later meeting after the panelists have had ample time to assimilate and analyze the comments raised at the Consensus Development Conference.

In sum, the Panel of Review agrees that, in general, the final report of the Task Force on Cesarean Childbirth integrated the data, Task Force conclusions, and the contributions made by the audience.