Vaginal Birth After Cesarean Delivery

Although labor and birth are physiologic processes that have not changed in essence since women began to walk upright, obstetrical and midwifery guidelines have changed and evolved socially, culturally, and scientifically. This evolution has greatly benefited women, babies, and families as childbirth has become safer and more predictable. The progression and acceptance of evidence-based care has been slow in obstetrics but is improving. Archie Cochrane chose obstetrics for his first Cochrane review, because he felt that obstetrics was the specialty least invested in evaluation and adaptation of current evidence. The American College of Obstetricians and Gynecologists (ACOG) began issuing ACOG practice bulletins in 1998, with the aim of supplying obstetrical providers with current information and assistance with evidence-based decision making. The practice bulletins are subtitled as Clinical Management Guidelines for Obstetrician-Gynecologists. Practice bulletin number 115 was recently published in August 2010. As the obstetrical evidence grows and evolves, the practice bulletins have been updated with newer versions. For example, in 2009, 6 practice bulletins were replaced with versions more in line with current evidence. The topics covered by the newer practice bulletins include “Management of Stillbirth,” “Polycystic Ovarian Syndrome and Cervical Cytology Screening,” among other subjects. Relevant to the perinatal nurse are newer practice bulletins on “Induction of Labor and Intrapartum Fetal Heart Rate Monitoring.” Some of the new practice bulletins replaced previous practice bulletins originally published as early as 1999, while one of the new practice bulletins replaced a practice bulletin published in May 2009. Practice bulletin number 115 was published in August 2010 and is the fourth ACOG practice bulletin on “Vaginal Birth After Previous Cesarean Delivery” (VBAC).1–4 A review of the evolution of the 4 practice bulletins gives insight into the development of evidence-based guidelines. Practice bulletin number 2, VBAC, was published in October 1998. This was the first ACOG practice bulletin on VBAC. All 4 practice bulletins are titled the same, so each bulletin will be referred to by number. The practice bulletins on VBAC are number 2, October 1998; number 5, July 1999; number 54, July 2004; and number 115, August 2010. Practice bulletin number 2 and practice bulletin number 5 are virtually identical. These 2 bulletins have the same summary and recommendations and the same reference list. All evidences in the ACOG practice bulletins are evaluated for quality according to the methods described by the US preventive services task force (Table 1).4 Recommendations are graded from level A to level C (Table 2).5 The ACOG utilizes MEDLINE, the Cochrane Database, and ACOG practice bulletins and committee opinions in the formulation of recommendations. Unpublished research is not used, even if this research has been presented at conferences or meetings. Articles published only in english are reviewed.Table 1: Levels of evidenceTable 2: Levels of recommendationsAs the evidence and research surrounding VBAC grew, the references for the practice bulletins increased. Bulletin number 2 and bulletin number 5 have 71 references, bulletin number 54 has 105 references, and bulletin number 115 has 136 references. “Vaginal Birth After Previous Cesarean Delivery” was a fairly new concept in 1998, the year the first practice bulletin on the subject was published. At that time, the level of evidence in the reference list was approximately 57% on level l or level II. References for bulletin number 54 in 2004 were about 61%-level I or level II evidence. By 2010, the evidence referenced in bulletin number 115 was 80% on level I or level II. This increase reflects the increasing amount of research-following women who chose a trial of labor after cesarean (TOLAC). Interestingly, the rate of TOLAC and VBAC was decreasing during this time period because of the recommendations in bulletin number 54, which were interpreted by clinicians both to prohibit TOLAC after more than 1 previous cesarean delivery and to limit TOLAC to tertiary care centers with in-house obstetrics and anesthesia. In an editorial in Obstetrics and Gynecology in June 2010, Dr James Scott6 acknowledges that each new revision of the VBAC practice bulletin led to unintended consequences. Those consequences included the denial to some women of the chance for TOLAC and the inability of some physicians to provide a standard of care, which the physician felt was safe and appropriate. Comparison of recommendations for TOLAC and VBAC for women with more than 1 previous cesarean delivery reveals the importance of continuing to build evidence for safety in maternity care and for careful reevaluation of guidelines on the basis of current evidence. Practice bulletin number 54, 2004, references only 1 study following women who were attempting VBAC after 2 previous cesarean deliveries that control for confounding variables.7 In that study, women attempting a TOLAC after 2 previous cesarean deliveries had a nearly 5 times greater risk of uterine rupture those attempting a TOLAC after 1 previous cesarean delivery. This 1 study greatly influenced the statement in the practice bulletin that women with 2 previous cesarean deliveries should not attempt TOLAC unless they had also had a previous vaginal delivery. However, because of the paucity of evidence, the statement limiting vaginal delivery did not appear in the “Summary” recommendations. Despite this lack of inclusion in the “Summary” recommendations, this suggestion became policy in many institutions. Two large studies looking at uterine rupture were published in 2005 and 2006.8,9 One of these studies found no increased risk of rupture after more than 1 previous cesarean delivery, and the other study found that the risk of uterine rupture increased from 0.9% to 1.8%. Both studies found that the success rate for VBAC was similar in women with 1 previous cesarean delivery and in those with more than 1 cesarean delivery. Practice bulletin number 115, 2010, states that TOLAC would be a reasonable option to offer women who had 2 previous cesarean deliveries, even if they had not ever had a vaginal birth. This option is listed in the practice bulletin as a level B recommendation. This application of evidence to practice and ACOG guidelines has expanded options for birthing women and their providers. The increasing use of evidence to develop guidelines for practice has also led to greater transparency in medical decision making. Patients are sometimes well acquainted with the available published research and may seek an enlarged role in their own care. Practice bulletin number 115 unmistakably encourages physicians to develop partnerships with the women they care for, including in the level C recommendations, a statement supporting respect for patient autonomy and frank discussion of risk, benefit, and management alternatives regarding TOLAC and VBAC. Although not referenced or specifically recommended in practice bulletin number 115, the language in the “Summary” includes healthcare providers rather than physicians alone. Recognition that nurse-midwives manage TOLAC without increased untoward outcomes for women and infants is implicit in the “Summary.” The ACOG guidelines represent strategies and approaches to patient care that are supported by the best evidence to be had at the time the guidelines are written. Perinatal nurses can more easily keep up with the research and expert opinion in obstetrics by analysis and discussion of the ACOG practice bulletins with colleagues in nursing, medicine, and midwifery. The ACOG's readiness to continually reassess the evidence in the interest of providing the best care for women is commendable. Policy makers in healthcare may read the practice bulletins and develop unit standards that take advantage of the evidence available. However, care providers, including perinatal nurses, are encouraged to make use of all evidences obtainable, including nursing and midwifery literature. A critical eye and discussion will help with the application of research and evidence to contemporary practice. —Jackie Tillett, ND, CNM, FACNM Associate Clinical Professor University of Wisconsin School of Medicine and Public Health, Madison Director Midwifery and Wellness Center Aurora Sinai Medical Center Milwaukee, Wisconsin