Presented by

Eunice Kennedy Shriver National Institute of Child Health and Human Development
Office of Medical Applications of Research
of the National Institutes of Health

Cosponsors

National Institute of Nursing Research, NIH
Office of Research on Women’s Health, NIH

The Agency for Healthcare Research and Quality and the Centers for Disease Control and Prevention provided additional conference development support.

About the Consensus Development Program

The National Institutes of Health (NIH) Consensus Development Program has been organizing major conferences since 1977. The Program generates Evidence-based consensus statements addressing controversial issues important to healthcare providers, policymakers, patients, researchers, and the general public. The NIH Consensus Development Program holds an average of three conferences a year. The Program is administered by the Office of Medical Applications of Research within the NIH Office of the Director. Typically, the conferences have one major NIH Institute or Center sponsor, with multiple cosponsoring agencies.

Topic Selection

NIH Consensus Development and State-of-the-Science Conference topics must satisfy the following criteria:

• Broad public health importance. The severity of the problem and the feasibility of interventions are key considerations.

• Controversy or unresolved issues that can be clarified, or a gap between current knowledge and practice that can be narrowed.

• An adequately defined base of scientific information from which to answer conference questions such that the outcome does not depend primarily on subjective judgments of panelists.

Conference Type

Two types of conferences fall under the purview of the NIH Consensus Development Program: State-of-the-Science Conferences and Consensus Development Conferences. Both conference types utilize the same structure and methodology; they differ only in the strength of the evidence surrounding the topic under consideration. When it appears that there is very strong evidence about a particular medical topic, but that the information is not in widespread clinical practice, a Consensus Development Conference is typically chosen to consolidate, solidify, and broadly disseminate strong Evidence-based recommendations for general practice. Conversely, when the available evidence is weak or contradictory, or when a common practice is not supported by high-quality evidence, the State-of-the Science label is chosen. This highlights what evidence about a topic is available and what directions future research should take, and alerts physicians that certain practices are not supported by good data.

Conference Process

Before the conference, a systematic evidence review on the chosen topic is performed by one of the Agency for Healthcare Research and Quality’s Evidence-based Practice Centers. This report is provided to the panel members approximately 6 weeks prior to the conference, and posted to the Consensus Development Program Web site once the conference begins, to serve as a foundation of high-quality evidence upon which the conference will build.

The conferences are held over 2-1/2 days. The first day and a half of the conference consist of plenary sessions, in which invited expert speakers present information, followed by “town hall forums,” in which open discussion occurs among the speakers, panelists, and the general public in attendance. The panel then develops its draft statement on the afternoon and evening of the second day, and presents it on the morning of the third day for audience commentary. The panel considers these comments in executive session and may revise its draft accordingly. The conference ends with a press briefing, during which reporters are invited to question the panelists about their findings.

Panelists

Each conference panel comprises 12 to 16 members, who can give balanced, objective, and informed attention to the topic. Panel members:

• Must not be employees of the U.S. Department of Health and Human Services.

• Must not hold financial or career (research) interests in the conference topic.

• May be knowledgeable about the general topic under consideration, but must not have published on or have a publicly stated opinion on the topic.

• Represent a variety of perspectives, to include:
  – Practicing and academic health professionals

  
  – Biostatisticians and epidemiologists

  – Clinical trialists and researchers

  – Non-health professionals with expertise in fields relevant to the specific topic (ethicists, economists,
     attorneys, etc.)

  – Individuals representing public-centered values and concerns

In addition, the panel as a whole should appropriately reflect racial and ethnic diversity. Panel members are not paid a fee or honorarium for their efforts. They are, however, reimbursed for travel expenses related to their participation in the conference.

Speakers

The conferences typically feature approximately 21 speakers: 3 present the information found in the Evidence-based Practice Center’s systematic review of the literature; the other 18 are experts in the topic at hand, have likely published on the topic, and may have strong opinions or beliefs on the topic. Where multiple viewpoints on a topic exist, every effort is made to include speakers who address all sides of the issue.

Conference Statements

The panel’s draft report is released online late in the conference’s third and final day. The final report is released approximately 6 weeks later. During the intervening period, the panel may edit its statement for clarity and correct any factual errors that might be discovered. No substantive changes to the panel’s findings are made during this period.

Each Consensus Development or State-of-the-Science Conference Statement reflects an independent panel’s assessment of the medical knowledge available at the time the statement is written; as such, it provides a “snapshot in time” of the state of knowledge on the conference topic. It is not a policy statement of the NIH or the Federal Government.

Dissemination

Consensus Development and State-of-the-Science Conference Statements have robust dissemination:

• A press briefing is held on the last day of the conference to assist journalists in preparing news stories on the conference findings.

• The statement is published online at consensus.nih.gov.

• The conference statement is published in a major peer-reviewed journal.

• Print copies are mailed to a wide variety of targeted audiences and are available at no charge through a clearinghouse.

Contact Us

For conference schedules, past statements, and evidence reports, please contact us:

NIH Consensus Development Program Information Center
P.O. Box 2577
Kensington, MD 20891
888–NIH–CONSENSUS (888–644–2667)
consensus.nih.gov

Upcoming Conferences

NIH State-of-the-Science Conference:	Preventing Alzheimer’s Disease and Cognitive Decline April 26–28, 2010
NIH Consensus Development Conference:	Inhaled Nitric Oxide Therapy for Premature Infants October 27–29, 2010

To receive registration notifications and updates about conferences and other program activities, please join the NIH Consensus Development Program Information Network at consensus.nih.gov/alerts.htm.

Recent Conferences

NIH Consensus Development Conference	Lactose Intolerance and Health February 22–24, 2010
NIH State-of-the-Science Conference:	Enhancing Use and Quality of Colorectal Cancer Screening February 2–4, 2010
NIH State-of-the-Science Conference:	Diagnosis and Management of Ductal Carcinoma In Situ (DCIS) September 22–24, 2009
NIH State-of-the-Science Conference:	Family History and Improving Health August 24–26, 2009
NIH Consensus Development Conference:	Management of Hepatitis B October 20–22, 2008
NIH Consensus Development Conference:	Hydroxyurea Treatment for Sickle Cell Disease February 25–27, 2008
NIH State-of-the-Science Conference:	Prevention of Fecal and Urinary Incontinence in Adults December 10–12, 2007
NIH State-of-the-Science Conference:	Tobacco Use: Prevention, Cessation, and Control June 12–14, 2006
NIH State-of-the-Science Conference:	Multivitamin/Mineral Supplements and Chronic Disease Prevention May 15–17, 2006
NIH State-of-the-Science Conference:	Cesarean Delivery on Maternal Request March 27–29, 2006
NIH State-of-the-Science Conference:	Manifestations and Management of Chronic Insomnia in Adults June 13–15, 2005
NIH State-of-the-Science Conference:	Management of Menopause-Related Symptoms March 21–23, 2005

To access previous conference statements, videocasts, evidence reports, and other conference materials, please visit consensus.nih.gov.

Background

Vaginal birth after cesarean (VBAC) is the delivery of a baby through the vagina after a previous cesarean delivery. For most of the 20th century, once a woman had undergone a cesarean (the delivery of a baby through an incision made in the abdominal wall and uterus), many clinicians believed that all of her future pregnancies would require delivery by cesarean as well. However, in 1980, a National Institutes of Health (NIH) Consensus Development Conference panel questioned the necessity of routine repeat cesarean deliveries and outlined situations in which VBAC could be considered. The option for a woman with a previous cesarean delivery to try to labor and deliver vaginally, rather than to plan a cesarean delivery, was therefore offered and exercised more often from the 1980s through the early 1990s. Since 1996, however, VBAC rates in the United States have consistently declined, while cesarean delivery rates have been steadily rising.

The exact causes of these shifts are not entirely understood. A frequently cited concern about VBAC is the possibility of uterine rupture during labor, because a cesarean delivery leaves a scar in the wall of the uterus at the incision site, which is weaker than other uterine tissue. Attempted VBAC may also be associated with endometritis (infection of the lining of the uterus), the need for a hysterectomy (removal of the uterus), and blood transfusion, as well as neurologic injury to the baby. However, repeat cesarean delivery may also carry a risk of bleeding or the need for a hysterectomy, uterine infections, and respiratory problems for the newborn. In addition, multiple cesarean deliveries may be associated with placental problems in future pregnancies. Other important considerations that may influence the decision include the number of previous cesarean deliveries a woman has experienced; the surgical incision used during previous cesarean delivery; the reason for the previous surgical delivery; the woman’s age; how far along the pregnancy is, relative to her due date; and the size and position of the baby. Given the complexity of this issue, a thorough examination of the relative balance of benefits and harms to mother and baby will be of immediate utility to practitioners and pregnant women in deciding on a planned mode of delivery.

A number of nonclinical factors are involved in this decision as well, and may be influencing the decline in VBAC rates. Some individual practitioners and hospitals in the United States have decreased or eliminated their use of VBAC. Professional society guidelines may influence utilization rates because some medical centers do not offer the recommended supporting services for a trial of labor after cesarean (e.g., immediate availability of a surgeon who can perform a cesarean delivery and onsite anesthesiologists). Information related to complications of an unsuccessful attempt at VBAC, medico-legal concerns, personal preferences of patients and clinicians, and insurance policies and economic considerations may all play a role in changing practice patterns. Improved understanding of the clinical risks and benefits, and how they interact with legal, ethical, and economic forces to shape provider and patient choices about VBAC, may have important implications for health services planning.

To advance understanding of these important issues, the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the NIH Office of Medical Applications of Research have convened a Consensus Development Conference, March 8–10, 2010. The conference will address the following key questions:

• What are the rates and patterns of utilization of trial of labor after prior cesarean, vaginal birth after cesarean, and repeat cesarean delivery in the United States?


• Among women who attempt a trial of labor after prior cesarean, what is the vaginal delivery rate, and the factors that influence it?


• What are the short- and long-term benefits and harms to the mother of attempting trial of labor after prior cesarean versus elective repeat cesarean delivery, and what factors influence benefits and harms?


• What are the short- and long-term benefits and harms to the baby of maternal attempt at trial of labor after prior cesarean versus elective repeat cesarean delivery, and what factors influence benefits and harms?


• What are the nonmedical factors that influence the patterns and utilization of trial of labor after prior cesarean?


• What are the critical gaps in the evidence for decision-making, and what are the priority investigations needed to address these gaps?

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About the Artwork

The illustration on this volume’s cover and used on a variety of materials associated with the conference depicts a mobile hanging over an infant’s crib. In addition to some traditional playthings, this mobile’s hanging elements hint at the delicate balance of issues to be considered by expectant parents and healthcare providers in whether to attempt a vaginal birth after a prior cesarean delivery.

The image was conceived and created by Bonnie Hamalainen of NIH’s Division of Medical Arts and is in the public domain. No permission is required to use the image. Please credit “Bonnie Hamalainen/NIH Medical Arts.”

Agenda

Monday, March 8, 2010

8:30 a.m.      Introduction and Opening Remarks

Alan E. Guttmacher, M.D.

Acting Director

Eunice Kennedy Shriver National Institute
  of Child Health and Human Development

National Institutes of Health

8:40 a.m.      Charge to the Panel

Jennifer M. Croswell, M.D., M.P.H.

Acting Director

Office of Medical Applications of Research

Office of the Director

National Institutes of Health

8:50 a.m.      Conference Overview and Panel Activities

F. Gary Cunningham, M.D.

Panel and Conference Chairperson

Beatrice and Miguel Elias Distinguished
  Chair in Obstetrics and Gynecology

Professor

Department of Obstetrics and Gynecology

University of Texas Southwestern Medical Center at Dallas

9:00 a.m.     Overview of the Topic

Caroline Signore, M.D., M.P.H.

Medical Officer

Pregnancy and Perinatology Branch

Eunice Kennedy Shriver National Institute of Child Health and Human Development

I.	What Are the Rates and Patterns of Utilization of Trial of Labor After Prior Cesarean, Vaginal Birth After Cesarean, and Repeat Cesarean Delivery in the United States?

9:15 a.m.      Trends and Patterns of Vaginal Birth After Cesarean Availability in the United States

Kimberly D. Gregory, M.D., M.P.H.

Vice Chairperson

Women’s Healthcare Quality and Performance Improvement

Department of Obstetrics and Gynecology

Cedars-Sinai Medical Center

II.	Among Women Who Attempt a Trial of Labor After Prior Cesarean, What Is the Vaginal Delivery Rate and the Factors That Influence It?

9:35 a.m.     Evidence-based Practice Center Presentation I: Trial of Labor, Vaginal Delivery Rates, and Relevant Factors

Karen B. Eden, Ph.D.

Investigator/Associate Professor

Department of Medical Informatics and Clinical Epidemiology

School of Medicine

Oregon Health & Science University

9:55 a.m.     Rates and Prediction of Successful Vaginal Birth After Cesarean

William A. Grobman, M.D., M.B.A.

Associate Professor

Division of Maternal Fetal Medicine

Department of Obstetrics and Gynecology

Feinberg School of Medicine

Northwestern University

10:15 a.m.   Discussion

Participants with questions or comments for the speakers should proceed to the designated microphones and wait to be recognized by the panel chairperson. Please state your name and affiliation. Questions and comments not heard before the close of the discussion period may be submitted on the computers in the registration area. Please be aware that all statements made at the microphone or submitted later are in the public domain.

III.	What Are the Short- and Long-Term Benefits and Harms to the Mother of Attempting Trial of Labor After Prior Cesarean Versus Elective Repeat Cesarean Delivery, and What Factors Influence Benefits and Harms?

10:45 a.m.   Evidence-based Practice Center Presentation II: Maternal Benefits and Harms, and Relevant Factors

Jeanne-Marie Guise, M.D., M.P.H.

Principal Investigator/Associate Professor

Departments of Obstetrics and Gynecology, and Medical Informatics
    and Clinical Epidemiology

School of Medicine

Oregon Health & Science University

11:05 a.m.    Birth After Prior Cesarean Delivery: Short-Term Maternal Outcomes

Mona T. Lydon-Rochelle, Ph.D., M.P.H., CNM

Perinatal Epidemiologist

National Perinatal Epidemiology Centre

Anu Research Centre

Cork University Maternity Hospital

Associate Professor

Department of Epidemiology and Public Health

University College Cork

11:25 a.m.   Discussion

11:45 a.m.    Lunch

Panel Executive Session

12:45 p.m.    Delivery After Previous Cesarean: Long-Term Maternal Outcomes

Robert M. Silver, M.D.

Professor and Chief

Division of Maternal-Fetal Medicine

Department of Obstetrics and Gynecology

University of Utah Health Sciences Center

1:05 p.m.      Predicting Uterine Rupture in Women Undergoing Trial of Labor After Prior Cesarean Delivery

Mark B. Landon, M.D.

Professor and Director

Division of Maternal-Fetal Medicine

Department of Obstetrics and Gynecology

The Ohio State University College of Medicine

1:25 p.m.     Discussion

IV.	What Are the Short- and Long-Term Benefits and Harms to the Baby of Maternal Attempt at Trial of Labor After Prior Cesarean Versus Elective Repeat Cesarean Delivery, and What Factors Influence Benefits and Harms?

1:45 p.m.      Evidence-based Practice Center Presentation III: Infant Benefits and Harms, and Relevant Factors

Cathy Emeis, Ph.D., CNM

Investigator/Assistant Professor

Department of Primary Care

School of Nursing

Oregon Health & Science University

2:05 p.m.      Delivery After Previous Cesarean: Short-Term Perinatal Outcomes

Lucky Jain, M.D., M.B.A.

Richard W. Blumberg Professor and Executive Vice Chairperson

Department of Pediatrics

Emory University School of Medicine

2:25 p.m.      Delivery After Previous Cesarean: Long-Term Outcomes in the Child

T. Michael O’Shea, M.D., M.P.H.

Professor

Department of Pediatrics

Chief

Department of Neonatal and Perinatal Medicine

Neonatology Division of Pediatrics

School of Medicine

Wake Forest University

2:45 p.m.      Vaginal Birth After Cesarean Synthesis: Overview of Efficacy and Safety of Vaginal Birth After Cesarean

George A. Macones, M.D., M.S.C.E.

Professor and Chairperson

Department of Obstetrics and Gynecology

Washington University School of Medicine

3:05 p.m.      Discussion

V.	What Are the Nonmedical Factors That Influence the Patterns and Utilization of Trial of Labor After Prior Cesarean?

3:45 p.m.      Trial of Labor Versus Elective Repeat Cesarean: An Administrator’s Perspective

Michael L. Socol, M.D.

Thomas J. Watkins Memorial Professor and Vice Chairperson

Department of Obstetrics and Gynecology

Division of Maternal-Fetal Medicine

Feinberg School of Medicine

Northwestern University

4:15 p.m.      Evaluating Professional Society Guidelines on Vaginal Birth After Cesarean

Emmanuel Bujold, M.D., M.Sc., FRCSC

Associate Professor

Maternal Fetal Medicine and Perinatal Epidemiology

Jeanne et Jean-Louis Lévesque Perinatal
  Research Chair

Department of Obstetrics and Gynaecology

Faculty of Medicine

Laval University

Québec City, Québec

Canada

4:35 p.m.      Discussion

5:00 p.m.      Adjournment

Tuesday, March 9, 2010

8:30 a.m.      Impact of Anesthesiologists on the Incidence of Vaginal Birth After Cesarean in the United States: Role of Anesthesia Availability, Productivity, Guidelines, and Patient Safety

David J. Birnbach, M.D., M.P.H.

Professor

Departments of Anesthesiology, Obstetrics and Gynecology,
   and Public Health

Executive Vice Chairperson

Department of Anesthesiology

Director

Center for Patient Safety

Jackson Memorial Hospital

University of Miami

Associate Dean

Miller School of Medicine

University of Miami

8:50 a.m.      The Immediately Available Physician Standard

Howard Minkoff, M.D.

Distinguished Professor of Obstetrics and Gynecology

State University of New York–Downstate Medical Center

Chairperson

Department of Obstetrics and Gynecology

Maimonides Medical Center

9:10 a.m.      Understanding Risk, Patient and Provider Preferences, and Obstetric Decision-Making: Approach to Delivery After Cesarean

Miriam Kuppermann, Ph.D., M.P.H.

Professor

Departments of Obstetrics, Gynecology, & Reproductive Sciences,
  and Epidemiology & Biostatistics

University of California, San Francisco

9:30 a.m.      Discussion

10:00 a.m.    The Ethics of Vaginal Birth After Cesarean

Anne Drapkin Lyerly, M.D., M.A.

Associate Professor

Department of Obstetrics and Gynecology

Core Faculty

Trent Center for Bioethics, Humanities, and History of Medicine

Duke University

10:20 a.m.    Mothers’ Stories

Rita Rubin

Medical Reporter

USA Today

10:40 a.m.    Vaginal Birth After Cesarean Section: Views From the Private Practitioner

Chet Edward Wells, M.D.

Professor

Department of Obstetrics and Gynecology

University of Texas Southwestern Medical Center at Dallas

11:00 a.m.     Discussion

11:30 a.m.     Adjournment

Wednesday, March 10, 2010

9:00 a.m.      Presentation of the Draft Consensus Statement

The panel chairperson will read the draft statement to the assembled audience.

9:30 a.m.      Public Discussion

The panel chairperson will call for questions and comments from the audience on the draft statement, beginning with the introduction and continuing through each subsequent section, in turn. Please confine your comments to the section under discussion. The chairperson will use discretion in proceeding to subsequent sections so that comments on the entire statement may be heard during the time allotted. Participants with comments should proceed to the designated microphones and wait to be recognized by the panel chairperson. Please state your name and affiliation. Questions and comments not heard before the close of the discussion period may be submitted on the computers in the registration area. For participants viewing the remote Webcast, comments may be submitted online at consensus.nih.gov/comments.htm. Comments will not be accepted after 11:30 a.m. Please be aware that all statements made at the microphone or submitted later are in the public domain.

11:00 a.m.    Adjournment
Panel Meets in Executive Session

The public portion of the conference ends at 11:00 a.m. The panel meets in its last executive session to review public comments on the draft statement. 

2:00 p.m.      Press Telebriefing

The panel will provide a summary of its findings to the press and will answer questions from reporters via telebriefing. Only members of the press are permitted to ask questions of the panel during this time. Interested conference participants who are not members of the press may call in (from a remote location) to listen to the live telebriefing. Please go to consensus.nih.gov for instructions on joining the call.

The panel’s draft statement will be posted to consensus.nih.gov as soon as possible after the close of proceedings, and the final statement will be posted 4 to 6 weeks later.

Abstracts

The abstracts are designed to inform the panel and conference participants, as well as to serve as a reference document for any other interested parties. We would like to thank the speakers for preparing and presenting their findings on this important topic.

The organizers would also like to thank the planning committee, the panel, the Oregon Evidence-based Practice Center, and the Agency for Healthcare Research and Quality. We would also like to thank the National Institute of Nursing Research and the Office of Research on Women's Health. We appreciate your continued interest in both the NIH Consensus Development Program and the area of vaginal birth after cesarean delivery.

Please note that where multiple authors are listed on an abstract, the underline denotes the presenting author.

Trends and Patterns of Vaginal Birth After Cesarean
Availability in the United States

Kimberly D. Gregory, M.D., M.P.H.; Moshe Fridman, Ph.D.;
Lisa Korst, M.D., Ph.D.

National Trends in Vaginal Birth After Cesarean (VBAC)

Since the advent of cesarean birth and the survival of the first patient, the question of what to do with subsequent pregnancy has been a topic of debate with case series publications dating back as early as 1959 establishing what is widely known and accepted today—VBAC is possible, is successful approximately 70% of the time, and is associated with uterine rupture approximately 1% of the time.¹

Three overlapping series of events or phenomena led to the widespread uptake of VBAC across the country. The first event was the National Institutes of Health Consensus Conference on Cesarean Childbirth in 1981.² The meeting ended with a series of recommendations to decrease the overall national cesarean rate, most prominent of which was to increase the utilization of VBAC. Second, in recognition of the growing body of literature supporting VBAC, and concurrent with the evolution of practice guideline development, the American College of Obstetricians and Gynecologists (ACOG) published a series of guidelines that were successively less restrictive.^3–7 The 1995 guideline was perhaps the most liberal and strongest endorsement, stating that “…all women ‘should’ undergo VBAC unless medical or obstetrical contraindications.”⁸ The third phenomenon contributing to the increase in VBAC utilization was interest by policymakers and third-party payers. The net effect of these phenomenal events led to the highest VBAC rate ever reported in the United States at 28.3% in 1996^9,10 (see Figure 1).

Since 1996, the national rate has plummeted to as low as 8.5%.¹⁰ The decline appears to have started around 1997, shortly after a publication by McMahon et al.¹¹ The publicity surrounding McMahon’s study solidified in the public’s eye the risks of adverse outcomes associated with failed trial of labor. Notably, adverse outcomes (uterine rupture, hysterectomy, transfusion, “major operative injury,” maternal or newborn death) are more likely with failed VBAC. Further decline in the national VBAC rate was noted after the release of an updated ACOG practice bulletin released in 1999.¹² In response to both ongoing patient safety concerns emphasized by the McMahon paper, as well as clinician concerns about malpractice liability, the language of ACOG’s recommendation was altered such that instead of “encouraging” VBAC, women should be “offered” VBAC if no contraindications, in settings where a physician capable of performing a cesarean is “immediately” available throughout active labor, in institutions equipped to respond to emergencies.^7,12 In the current medico-legal climate, the health system personnel requirements became burdensome for both physicians and hospitals and directly contributed to the abolition of VBAC at some facilities.^13,14

Factors Associated With Variation in VBAC Utilization

Regional Variation

In all states, across all hospital types, and for most women independent of age, race, or clinical conditions, the cesarean rate is going up and the VBAC rate is going down.^9,10 As shown in Table 1, using data from the Nationwide Inpatient Sample for the years 2000, 2003, and 2005 to calculate national cesarean and VBAC rates, the elective repeat cesarean rate increased during this time period (from 59% to 83%), while the VBAC process measures (VBAC attempt rate and VBAC success rate) as well as the overall VBAC rate declined.¹⁵

Table 1.  Method of Delivery for Women With Prior Cesareans, Nationwide Inpatient Sample, 2000, 2003, 2005

Patient Variation

Since 1996, VBAC utilization has decreased across all age groups.^9,10 Likewise, the VBAC rate has declined for all racial/ethnic groups.¹⁰ Several recent studies suggest that black women were more likely to attempt and fail VBAC, when compared to other ethnic groups.^16,17 Cesarean and VBAC rates vary by insurance status, and patient-specific clinical characteristics impact VBAC success.^2,18–28 Gregory et al. stratified patients into high risk (one or more maternal, fetal, or placental condition) and low risk (no conditions) and found attempted and successful VBAC rates varied widely by these conditions, ranging from 10–73%.²⁸ Similar findings by other investigators suggest that there may be promise in the development of models to predict ideal VBAC candidates or patients at increased risk for adverse events.^29–34 Several models have been proposed, but none has been integrated into standard obstetrical practice.

International Data

Publications from Europe consistently demonstrate that the majority of women with prior cesarean attempt VBAC (attempted VBAC rates approach 50–70%) with success rates ranging from 70–75%.^35–41 It is noteworthy that, unlike the United States, the model of care in these countries relies heavily on nurse midwives.

Access to VBAC

Decline in VBAC utilization is due, in part, to decreased access.^13,14,42,43 Physicians practicing in rural and suburban areas reported the largest decline in the use of VBAC/trial of labor.43 In surveys of hospital administrators, approximately 30% of hospitals stated they stopped allowing VBAC services.^13,14 Of the hospitals that still allow VBAC, more than half had to change their policies to be compliant with ACOG recommendations.

Gaps in Knowledge About VBAC

Since the risks of VBAC and elective repeat cesarean delivery are not directly comparable, how do clinicians communicate these risks to women so that they can make informed decisions?44 Who should communicate these risks? Clearly physicians are stakeholders in the outcome, and what they say and how they say it influences patient choices. Attitudes about childbirth, fear of labor, and perceptions about womanhood and vaginal birth are cultural phenomenon influenced by society, spouse, family, friends, and personal values. Women need to have access to non-biased, evidence-based information to engage in a collaborative partnership of equals with midwives and obstetricians.^45,46 What are the incentives and resources for the medical profession to develop this nonbiased evidence base? How and whether to use decision tools, and what type is the most meaningful/helpful for the patient? How and when do patient preferences get integrated into the decision-making process for VBAC?⁴⁵ Hierarchically, randomized trials are considered the gold standard for evaluating outcome and effectiveness. Are patients and obstetricians ready to subject the “natural” process of vaginal birth to a trial? Dodd et al. offer justification for a randomized trial and a patient preference study of planned VBAC versus planned repeat cesarean.⁴⁷ In conclusion, in addition to a better knowledge base about how to communicate risks and benefits to patients in a meaningful manner, clinicians need a better set of tools to bring about more rapid dissemination and change in provider practices. In the United States, where choice and autonomy are perceived as a basic human right, it is unlikely that a blanket universal VBAC policy will ever be possible. At best, one can hope for refined prediction tools that maximize success and minimize failure, and a healthcare system that maintains and perhaps even improves access so that those women who want to choose VBAC will be able to do so.

References

1. Cohen B, Atkins M. Brief history of vaginal birth after cesarean section. Clin Obstet Gynecol. 2001;44:604–608.



2. National Institutes of Health: Consensus Development Conference on Cesarean Childbirth. Pub. No. 82:2067. Washington, DC: NIH; 1981.



3. American College of Obstetricians and Gynecologists (ACOG). Committee Statement. Guidelines for Vaginal Delivery After a Cesarean Childbirth. Washington, DC: ACOG; January 1982.



4. American College of Obstetricians and Gynecologists (ACOG). Committee Statement. Guidelines for Vaginal Delivery After a Cesarean Birth. Washington, DC: ACOG; November 1984.



5. American College of Obstetricians and Gynecologists (ACOG). Guidelines for Vaginal Delivery After a Cesarean Birth. Committee Opinion No. 64. Washington, DC: ACOG; October 1988.



6. American College of Obstetricians and Gynecologists (ACOG). Vaginal Delivery After a Cesarean Birth. Washington, DC: ACOG; October 1994.



7. Zinberg S. Vaginal delivery after previous cesarean delivery: a continuing controversy. Clin Obstet Gynecol. 2001;44:561–570.



8. American College of Obstetricians and Gynecologists (ACOG). Vaginal Delivery After a Cesarean Birth. Practice Patterns No. 1. Washington, DC: ACOG; August 1995.



9. Martin JA, Hamilton BE, Sutton PD, et al. Births: final data for 2004. Natl Vital Stat Rep. 2006;55(1).



10. Martin JA, Hamilton BE, Sutton PD, et al. Births: final data for 2006. Natl Vital Stat Rep. 2009;57(7).



11. McMahon MJ, Luther ER, Bowes WA, et al. Comparison of a trial of labor with an elective second cesarean section. N Engl J Med. 1996;335:689–695.



12. American College of Obstetricians and Gynecologists. Vaginal Birth After Previous Cesarean Delivery. ACOG Practice Bulletin No. 5. 1999;1106–1112.


13. Shihady IR, Broussard P, Bolton LB, et al. Vaginal birth after cesarean: do California hospital policies follow national guidelines? J Reprod Med. 2007;52:349–358.



14. Roberts RG, Deutchman M, King VJ et al. Changing policies on vaginal birth after cesarean: impact on access. Birth. 2007;34:316–322.



15. Agency for Healthcare Research and Quality (AHRQ). Healthcare Cost and Utilization Project–Nationwide Inpatient Sample. Rockville, MD: AHRQ; 2005. (Unpublished data.)



16. Cahill AG, Samilio DM, Odibo AO, et al. Racial disparity in the success and complications of vaginal birth after cesarean delivery. Obstet Gynecol. 2008;111:654–658.



17. Hollard AL, Wing DA, Chung J. Ethnic disparity in the success of vaginal birth after cesarean delivery. J Matern Fetal Neonatal Med. 2006;19:483–487.



18. Mercer BM, Gilbert S, Landon MB, et al.; National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. Labor outcomes with increasing number of prior vaginal births after cesarean delivery. Obstet Gynecol. 2008;111:285–291.



19. Macones GA, Cahill A, Pare E, et al. Obstetric outcomes in women with two prior cesarean deliveries: is vaginal birth after cesarean delivery a viable option? Am J Obstet Gynecol. 2005;192:1223–1228.



20. Ford AA, Bateman BT, Simpson LL. Vaginal birth after cesarean delivery in twin gestations: a large nationwide sample of deliveries. Am J Obstet Gynecol. 2006;195:1138–1142.



21. Cahill A, Stamilio DM, Pare E, et al. Vaginal birth after cesarean (VBAC) attempt in twin pregnancies: is it safe? Am J Obstet Gynecol. 2005;193:1050–1055.



22. Varner MW, Leindecker S, Spong CY, et al.; National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. The Maternal-Fetal Medicine Unit Cesarean Registry: trial of labor with a twin gestation. Am J Obstet Gynecol. 2005;193:135–140.



23. Bujord E, Hammoud A, Schild C, Krapp M, Bauman P. The role of maternal body mass index in outcomes of vaginal births after cesarean. Am J Obstet Gynecol. 2005;193:1517–1521.



24. Hibbard JU, Gilbert S, Landon MB, et al.; National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. Trial of labor or repeat cesarean delivery in women with morbid obesity and previous cesarean delivery. Obstet Gynecol. 2006;108:125–133.



25. Quinones JN, Stamilio DM, Pare E, et al. The effect of prematurity on vaginal birth after cesarean delivery: success and maternal morbidity. Obstet Gynecol. 2005;105:519–524.



26. Durnwal CP, Rouse DJ, Leveno KJ, et al.; National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. The Maternal-Fetal Medicine Units Cesarean Registry: safety and efficacy of a trial of labor in preterm pregnancy after a prior cesarean delivery.Am J Obstet Gynecol. 2006;195:1119–1126.



27. Srinivas SK, Stamilio DM, Stevens EJ, et al. Safety and success of vaginal birth after cesarean delivery in patients with preeclampsia. Am J Perinat. 2006;23:145–152.



28. Gregory KD, Korst LM, Fridman M, et al. Vaginal birth after cesarean: clinical risk factors associated with adverse outcome. Am J Obstet Gynecol. 2008;198(452):e1–e10.



29. Grobman WA, Lai Y, Landon MB, et al. Development of a nomogram for prediction of vaginal birth after cesarean delivery. Obstet Gynecol. 2007;109:796–797.



30. Grobman WA, Lai Y, Landon MB, et al. Can a prediction model for vaginal birth after cesarean also predict the probability of morbidity related to a trial of labor? Am J Obstet Gynecol. 2009;200(56):e1–e6.



31. Grobman WA, Lai Y, Landon MB, et al. Prediction of uterine rupture associated with attempted vaginal birth after cesarean delivery. Am J Obstet Gynecol. 2008;199(30):31–35.



32. Hashima JN, Guise JM. Vaginal birth after cesarean: a prenatal scoring tool. Am J Obstet Gynecol. 2007;196:e22–e23.



33. Macones GA, Cahill AG, Samilio DM. Can uterine rupture in patients attempting vaginal birth after cesarean delivery be predicted? Am J Obstet Gynecol. 2007;195:1148–1152.



34. Harper LM, Macones GA. Predicting success and reducing the risks when attempting vaginal birth after cesarean. Obstet Gynecol Survey. 2008;63:538–545.



35. Case BD, Corcoran R, Jeffcoate N, et al. Cesarean section and its place in modern obstetric practice. J Obstet Gynaecol Br Commonw. 1971;78:203–214.



36. Selo-Ojeme D, Abulhassan N, Mandal R, et al. Preferred and actual delivery mode after a cesarean in London, UK. Int J Gynaecol Obstet. 2008;102(2):156–159.



37. Zwart JJ, Richters JM, Ory F, et al. Uterine rupture in the Netherlands: a nationwide population-based cohort study. BJOG. 2009;116(8):1069–1678.



38. Turner MJ, Agnew G, Langan H. Uterine rupture and labour after a previous low transverse caesarean section. BJOG. 2006;113:729–732.



39. Udayasankar V, Padmagirison R, Majoko F. National survey of obstetricians in Wales regarding induction of labour in women with a previous caesarean section. J Obstet Gynaecol. 2008;28(1):48–50.



40. Kwee A, Bots ML, Visser GH, et al. Obstetric management and outcome of pregnancy in women with a history of caesarean section in the Netherlands. Eur J Obstet Gynecol Reprod Biol. 2007;132(2):171–176.



41. Grossetti E, Vardon D, Creveuil C, et al. Rupture of the scarred uterus. Acta Obstet Gynecol Scand. 2007;86:572–578.



42. Coleman VH, Erickson K, Shulkin J, et al. Vaginal birth after cesarean delivery: practice patterns of obstetrician-gynecologists. J Reprod Med. 2005;50:261–266.



43. Gochnour G, Ratcliffe S, Stone MB. The Utah VBAC Study. Matern Child Health J. 2005;9(2):181–188.



44. Lyerly AD, Mitchel LM, Armstrong EM, et al. Risks, values, and decision making surrounding pregnancy. Obstet Gynecol. 2007;109:979–984.



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46. Emmett CL, Shaw ARG, Montgomery AA, et al.; DIAMOND Study Group. Women’s experience of decision making about mode of delivery after a previous caesarean section: the role of health professionals and information about health risks. BJOG. 2006;113:1438–1445.



47. Dodd JM, Crowther CA, Hiller JE. Birth after cesarean study―planned vaginal birth or planned elective repeat cesarean for women at term with a single previous cesarean birth: protocol for a patient preference study and randomized trial. BMC Pregnancy Childbirth. 2007;7:17.

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Evidence-based Practice Center Presentation I: Trial of
Labor, Vaginal Delivery Rates, and Relevant Factors

Jeanne-Marie Guise, M.D., M.P.H.; Mary Anna Denman, M.D.;
Cathy Emeis, Ph.D., CNM; Nicole Marshall, M.D.; Miranda Walker,
M.A.; Rongwei Fu, Ph.D.; Rosalind Janik; Peggy Nygren, M.A.;
Karen B. Eden, Ph.D.; Marian McDonagh, Pharm.D.

Introduction

Nearly one in three women (32.8%) were delivered by cesarean in 2007, the highest rate ever reported in the United States.¹ A major reason for the increase in cesareans is the rapid decline in vaginal birth after cesarean (VBAC) deliveries witnessed over the last decade. We undertook a systematic review to understand the incidence of trial of labor (TOL), VBAC, and the factors that influence it.

Methods

We searched MEDLINE^®, the Database of Abstracts of Reviews of Effectiveness, and the Cochrane databases (from 1980 through September 2009) for studies to estimate the trial of labor (TOL) and VBAC rates. To be included, studies had to be at least fair quality using U.S. Preventive Services Task Force quality criteria² and clearly define eligibility for TOL, as well as provide the number of women eligible for TOL, the number of women who had a TOL, and the number of women who had a VBAC. The overall strength of the body of evidence was rated (graded) using the methods described in the Methods Reference Guide for Effectiveness and Comparative Effectiveness Reviews used by the Evidence-based Practice Centers.^1,3 Studies of factors that influence TOL or VBAC (e.g., induction) also were reviewed to understand how those factors related to the reported rates.

Results and Discussion

Trial of Labor Rates

Thirty-five observational studies provided data on TOL. The overall TOL rate in studies conducted in the United States was 58%, with a range of 28% to 70%, compared with 64% among women in studies conducted outside the United States. Fewer women in studies conducted exclusively in term populations―both inside and outside the United States―had a TOL, 53% compared with 66% for studies that included any gestational age.

Factors That Predict Trial of Labor

Nine observational studies looked for factors known in the prenatal setting that may predict TOL. Three themes emerged from these studies: site of delivery, history of prior vaginal delivery, and race affected TOL. TOL was more likely in hospitals with higher delivery volumes, tertiary care centers, and teaching hospitals. Women with a prior vaginal delivery had more than double the likelihood of a TOL. Finally, nonwhite women were more likely to have a TOL than were white women.

Vaginal Birth After Cesarean

As the TOL rate is decreasing, it is important to examine what effect, if any, this has on the VBAC rate and what factors are contributing to vaginal delivery. Sixty-seven studies provided moderate strength of evidence for an overall summary estimate for VBAC of 74%. The rates of VBAC are highly variable in these studies. Most evidence of VBAC rates is from studies based in large tertiary care centers. While TOL rates have dropped over time, VBAC rates reported in observational studies have remained constant for women who have a TOL.

Induction of Labor and VBAC

Overall, the evidence regarding the rate of VBAC among women with induction of labor was low to moderate strength, indicating that 54–63% of these women will have a VBAC depending on the method of induction. Most studies were conducted in tertiary care settings. Less than half of these studies were conducted in the United States. The results were not stratified by age, race, ethnicity, or baseline obstetric or medical factors.

Factors That Predict Vaginal Birth After Cesarean

There is particular interest in whether demographic factors, nonclinical factors, and past obstetric factors may predict VBAC, since these factors are known prenatally and would allow clinicians to provide information on prognosis early in pregnancy. Twenty-three studies addressed predictive factors for VBAC.

Hispanic and African American women were more likely to have a TOL but less likely to have a VBAC compared with non-Hispanic and white women, respectively. Women at rural and private hospitals had a decreased likelihood of TOL and a decreased likelihood of VBAC. A prior history of vaginal delivery was consistently reported to increase likelihood of VBAC. Women delivering infants over 4 kilograms had a reduced likelihood of VBAC. Maximizing favorable clinical conditions such as waiting for a favorable cervical examination, if possible, improved the likelihood of VBAC.

Screening Tools for Predicting Vaginal Birth After Cesarean

The purpose of a screening tool is to help providers and patients better identify who will have a VBAC (and who is more likely to have a repeat cesarean delivery). Sophisticated mathematical models provide reasonable ability to identify women who are good candidates for VBAC, but none has discriminating ability to consistently identify women who are at risk for cesarean delivery.

References

1. Agency for Healthcare Research and Quality (AHRQ). Methods Reference Guide for Effectiveness and Comparative Effectiveness Reviews, Version 1.0. Rockville, MD: AHRQ; 2007.



2. Harris RS, Helfand M, Woolf S, et al. Current methods of the U.S. Preventive Services Task Force: a review of the process. Am J Prev Med. 2001;20(3 Suppl):21–35.



3. Deeks JJ, Dinnes J, D’Amico R, et al. Evaluating non-randomised intervention studies. Health Technol Assess. 2003;7(27):iii–x, 1–173.

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Rates and Prediction of Successful
Vaginal Birth After Cesarean

William A. Grobman, M.D., M.B.A.

There have been multiple observational studies that have assessed the probability that a woman who undertakes a trial of labor (TOL) after a previous cesarean will have a vaginal birth. These studies have demonstrated a population-level probability of a successful vaginal birth after cesarean (VBAC) that ranges between 60–80%.^1–3 However, within a population, the chances for an individual woman’s success may vary significantly on the basis of her particular characteristics and history.

Several demographic factors, including younger maternal age, lower maternal body mass index, and Caucasian race, have been consistently associated with a higher chance that a TOL results in a VBAC.^4–6 Women who are without medical illnesses that predate pregnancy, who have had a prior vaginal delivery, and whose prior cesarean was for an indication not related to arrest of labor also have higher chances of successful TOL.^4,7 Data regarding the number of prior cesareans have not consistently demonstrated marked differences in the chance of achieving VBAC.^8,9

Events that occur during the antepartum course of the current pregnancy of women who are considering a TOL also have been associated with the probability of achieving a VBAC. For example, a woman who develops preeclampsia appears to have a lower chance of successful TOL.¹⁰ Presenting for delivery at a lower gestational age with a more advanced (e.g., more dilated) cervical exam or with a fetus with a lower birth weight has been associated with a greater chance of VBAC.⁴ Spontaneous labor, in comparison to induction of labor, has been consistently associated with a greater chance of VBAC as well.¹¹

Lastly, several intrapartum factors may influence the probability that a TOL is successful.  Women who receive augmentation or have a nonreassuring fetal status have been reported to have a lower chance of VBAC, as do women who have received epidural analgesia.^4,12 It should be noted, however, that these factors are not equivalent to factors such as maternal age, given that intrapartum variables such as these may not be merely risk factors, but reflective of labor events that are directly related to or responsible for the failed TOL and corresponding cesarean.

Although the identification of these factors allows physicians to provide patients with some general guidance regarding the likelihood of achieving a VBAC, knowledge of these factors does not necessarily allow physicians to predict VBAC effectively. Even a strong association of a factor with an outcome does not guarantee that this factor predicts the outcome accurately.

Several investigators have attempted to develop models that could accurately predict whether a TOL would result in a VBAC.^12–21 Table 1 presents these studies as well as the different factors that have been incorporated into these models. As can be seen, many models have incorporated factors that are present at the start of prenatal care as well as factors that are not apparent until admission for delivery. Such models may be less useful for counseling women during their antepartum course, when they may start planning for their intended route of delivery. Other methodologic issues (e.g., no multivariable analysis, no formal evaluation of discriminatory accuracy) and limitations (e.g., scoring systems that result in a limited number of predictive categories, such that patients of very different risk may still appear to have an equivalent probability of VBAC) also have hampered the clinical usefulness of these predictive models.