Vaginal Birth After Cesarean Delivery

From Medscape Medical News
Draft NIH Consensus Statement Released
Laurie Barclay, MD

March 10, 2010 — An independent expert panel released today a draft consensus statement on vaginal birth after cesarean delivery (VBAC) at the close of a 3-day conference.

The National Institutes of Health (NIH) Consensus Development Conference on Vaginal Birth After Cesarean (VBAC): New Insights, was held from March 8-10 in Bethesda, Maryland. When choosing VBAC or repeat cesarean delivery, parents' preferences and risk factors should be carefully considered, the panel said.

VBAC was not generally accepted as a viable option until the 1980s. VBAC rates in the United States have increased steadily until they reached 28% in 1996, but they have consistently decreased since 1996, despite a steady increase in the rates of repeat cesarean delivery.

The current overall cesarean delivery rate is 31%, whereas the VBAC rate is less than 10%.

"The exact causes of these shifts are not known and are likely multifactorial," Catherine Y. Spong, MD, chief, and Caroline Signore, MD, medical officer, Pregnancy and Perinatology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, told Medscape Ob/Gyn & Women's Health.

"On one hand, the VBAC rate peaked in the mid-1990s, and then there was the publication of some studies that suggested increased risk with VBAC vs a repeat cesarean; at the same time, there was the malpractice crisis, especially in obstetrics, and the [American Congress of Obstetricians and Gynecologists] guidelines were modified to require that a physician capable of performing an emergency cesarean is immediately available through active labor. These events may have started the decline in VBAC utilization," Dr. Spong explained.

The panel noted that pregnant women, even those at low risk for complications, currently have limited access to clinicians and facilities capable of and willing to offer a trial of labor after previous cesarean delivery.

"Many women bemoan the fact that they have not had access to a trial of labor after prior cesarean section," Consensus Development Panel Chair F. Gary Cunningham, MD, Beatrice and Miguel Elias Distinguished Chair in Obstetrics and Gynecology at the University of Texas Southwestern Medical Center at Dallas, said during a telebriefing held after the conference.

The consensus conference aimed to explore the reasons underlying the changing practice patterns resulting in lower rates of VBAC, to clarify the clinical risks and benefits of both types of delivery procedures, and to describe the interaction of these risks with legal, ethical, and economic forces affecting clinician and patient choices regarding VBAC.

"A frequently cited concern [about VBAC] is the concern of safety — specifically the risk of uterine rupture, along with other risks," Dr. Spong and Dr. Signore said.
"In addition, there are nonclinical factors, including hospital practices and physician practices, professional society guidelines, medicolegal concerns, personal preferences of patients and clinicians, insurance policies, and economic considerations."

VBAC a Reasonable Option for Many

Despite the lack of widespread availability, a trial of labor is a reasonable option for many women with a previous cesarean delivery, and it is successful in nearly 75% of cases, the panel concluded.

Women in whom VBAC may be considered are those with 1 prior cesarean section, a single low transverse incision, singleton gestation, and no medical or obstetrical complicating conditions.
Data to support the safety of VBAC in women not meeting these criteria are lacking. Age itself does not preclude VBAC, but the rates of large babies, hypertension, diabetes, and dysfunctional labor are higher in older women.

Maternal mortality is lower for women who have a trial of labor, regardless of whether the baby is ultimately delivered vaginally or by cesarean section.
However, women who have an unsuccessful trial of labor and undergo repeat cesarean delivery have higher morbidity rates than those who have a successful VBAC.

Further complicating decision-making regarding VBAC is that benefits for the mother may come at the price of increased risks for the baby, and vice versa.
Although hysterectomy rates are similar for both forms of delivery, risk for uterine rupture is higher in women who have a trial of labor. VBAC has been linked to reduced abnormalities of placental growth and position in subsequent pregnancies. However, high-quality evidence about medical and nonmedical risk factors is limited or lacking.

"In general, there are short- and long-term risks and benefits for both the mother and the baby that need to be considered," Dr. Spong and Dr. Signore said. "Basically, they include — for the mother — risks of uterine rupture, transfusion and hemorrhage, operative risks including injury to the bowel and bladder, hysterectomy, death, infection, problems with placentation in subsequent pregnancies, [and] possible risk of stillbirth and ectopic pregnancies. For the baby, the risks include transition problems for the newborn, respiratory distress, neonatal encephalopathy and hypoxic ischemic encephalopathy, death, and brachial plexus injury."

Current VBAC Guidelines Should be Reassessed

The panel recommended that current VBAC guidelines from professional societies be reassessed, particularly the recommendation for "immediate availability" of surgical and anesthesia personnel before a trial of labor can be offered.

According to 2 recent surveys of hospital administrators, 30% of hospitals no longer offer a trial of labor or VBAC services because they could not meet the immediate availability standard suggested by the American College of Obstetricians and Gynecologists and the American Society of Anesthesiologists guidelines. However, the panel found no evidence that outcomes were improved by the immediate availability of surgical and anesthesia personnel.

" 'Nonmedical' factors affecting VBAC utilization [were also] considered at the conference, based on talks by expert presenters," Dr. Spong and Dr. Signore said. "The panel [considered], for example, the influence of hospital administrative policies, healthcare expenditures, resource utilization, the threat of malpractice litigation and the associated financial ramifications (insurance premiums, settlements and awards), the impact of professional society recommendations and standards, the role of maternal and provider preferences, understanding how risk is communicated and understood, the medical ethics of choice and access to childbirth options, and availability of surgical and anesthesiology staff."

Other Recommendations

Other recommendations of the panel are that malpractice concerns be addressed and that additional research be performed to better understand the medical and nonmedical factors that affect decision making for women with previous cesarean deliveries. Also needed are clear, evidence-based risk assessment tools to facilitate the decision-making process from early pregnancy through delivery, considering individual risk factors as well as maternal values and preferences.

"All women who have had a prior cesarean section should talk to their provider about VBAC and reassess the safety of a trial of labor," panel member Emily Spencer Lukacz, MD, MAS, associate professor of clinical reproductive medicine at the University of California–San Diego, said during the telebriefing.

Some women prefer to attempt a trial of labor because they would like their partner to be involved in the delivery, they perceive labor and vaginal delivery as deeply empowering, and/or they believe it will enhance maternal–infant bonding, breast-feeding, and recovery. In contrast, preferences favoring planned cesarean delivery include scheduling convenience, avoidance of labor pain or possible emergency cesarean section, and/or desire for surgical sterilization at the time of delivery.

The panels hopes the conference findings will have important implications for health services planning as well as for informed clinical decisions. The panel strongly urged policymakers and healthcare providers to collaborate in developing and implementing appropriate strategies to address and alleviate malpractice concerns.

"Pregnancy is something of a risky endeavor," concluded Carol J. Rowland Hogue, PhD, MPH, Jules & Uldeen Terry Professor of Maternal and Child Health at Emory University in Atlanta, Georgia. "Problems occur irrespective of the mode of delivery.... It's a tradeoff between making the pregnancy as safe as possible for the mother and making the pregnancy as safe as possible for the baby."

The statement issued by the impartial, independent Consensus Development Conference panel synthesized their evaluation of the available evidence from a systematic literature review prepared through the Agency for Healthcare Research and Quality Evidence-Based Practice Centers program by the Oregon Evidence-Based Practice Center. The panel included 15 experts in obstetrics and gynecology, urogynecology, maternal and fetal medicine, pediatrics, midwifery, clinical pharmacology, medical ethics, internal medicine, family medicine, perinatal and reproductive psychiatry, anesthesiology, nursing, biostatistics, epidemiology, healthcare regulation, and risk management, and a public representative.

The panel also considered evidence from expert presentations and audience input at the conference to provide a basis for informed patient and clinician decisions concerning VBAC. The statement also includes specific recommendations for future research.

The draft consensus statement is available on the NIH Consensus Development Program Web site.

NIH Consensus Development Conference on (VBAC): New Insights. March 8-10, 2010.