Background Questions

• What are the rates and patterns of utilization of trial of labor after prior cesarean, vaginal birth after cesarean, and repeat cesarean deliveries in the United States?
• What are the nonmedical factors (provider type, hospital type, etc.) that influence the patterns and utilization of trial of labor after prior cesarean?

Background questions will be addressed in the introduction of the report with information from reputable sources; however, these data are not part of the systematic review process.

Key Questions

1. Among women who attempt a trial of labor after prior cesarean, what is the vaginal delivery rate and the factors that influence it?
2. 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?
3. 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?
4. What are the critical gaps in the evidence for decision-making, and what are the priority investigations needed to address these gaps?

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?

Cesarean delivery rates continue to rise in the developed world. A recent report from the Organization for Economic Cooperation and Development (OECD) that provides health statistics and indicators for 30 countries, reports that the U.S. has one of the highest cesarean delivery rates in the world (Figure 2).¹²

Figure 2

Cesarean delivery by country - percent for live births (2007) . Note: Data for Norway, Ireland, Australia, United States, and Italy are from 2006

The cesarean delivery rate in the U.S. reached an all time high of 32.8 percent in 2007, far exceeding the national goal of 15 percent.^{1, 7} Though there are many potential causes, the decline in VBACs has certainly contributed to this trend. Cesarean delivery and VBAC rates differ considerably by state ranging from 2.5 to 20.9 percent (Figure 3).

Figure 3

Vaginal birth after cesarean rates* by state for 2006. *Percentage of women with a previous cesarean who then have a subsequent vaginal delivery

The effects of declining VBAC on cesarean rates are particularly pronounced after 1996. When the VBAC rate rapidly began to decline from a high of 28.3 percent in 1996 to its current low of 8.7 percent of live births, the cesarean rate climbed by more than 50 percent (from a rate of 20.7 percent in 1996, Figure 1).¹ Increases in cesarean delivery between 2006 and 2007 were reported for all age groups and for the three largest racial groups, white, Black, and Hispanic.⁸ The coupling of this trend with a concomitant increase in the primary cesarean delivery rate portends a continued escalation in the overall national cesarean delivery rate.

Both vaginal deliveries and cesareans hold inherent risks. Thus, mothers and clinicians are faced with complex decisions and must weigh possible risks and benefits associated with VBAC versus ERCD. How these decisions are made could have dramatic effects on the health of mothers and their children.

Patient decisionmaking. Several prior studies reported that up to half (48 percent) of women make decisions about a future trial of labor (TOL) before becoming pregnant again.^13–17 An additional 34 to 39 percent decide to have a TOL by the midpoint of the pregnancy.^{15, 17, 18}

A prior systematic review¹³ and several recent studies report that patients’ birth choices are complex and are driven by multiple competing factors. Women are balancing perceived health risks to themselves and their infants while also processing prior birth experiences and family and societal influences.^{13, 18, 19} Few studies have examined the reasons behind women’s decisions for ERCD or VBAC.^{15, 20} Table 1 lists the reasons behind women’s decisions for ERCD by study.

Table 1

Reasons behind women’s decisions for repeat cesarean delivery.

A woman’s perception of self-efficacy^{21, 22} and inability to fulfill family obligations²² have been cited as reasons for women choosing VBAC. Patient involvement in decisionmaking as well as VBAC counseling and educational programs have also been associated with increased choice for VBAC, in addition to increased patient satisfaction.^23–27 The timing of VBAC education seems to be important, with earlier timing of VBAC education in pregnancy being associated with higher TOL rates.^{27, 28} Conversely, two studies, one out of Scotland and one from the U.S., found that a lack of education or discussion with their clinician was associated with ERCD.^{23, 29} Interestingly, discussion of uterine rupture does not appear to have undue negative influence on patient decisionmaking.^{29, 30} Studies examining external influences on a woman’s choice for VBAC have found that women highly value the opinion of their healthcare provider^{18, 23, 29} and to a lesser extent sought input from their partners, family, friends, or other outside sources such as the Internet.^{18, 23}

Decision aids/interventions. Recently, decision aids have emerged to help a woman set priorities or understand her childbirth preferences, and ultimately help her make decisions. Decision aids are available in several formats: DVDs, paper booklets, and interactive computer or Web-based decision aids. Studies of VBAC decision aids have shown that they reduce a woman’s decisional conflict and increase knowledge scores; however, their impact on actual decisionmaking is uncertain.^31–34

What are the nonmedical factors (provider type, hospital type etc) that influence the patterns and utilization of trial of labor after prior cesarean?

Despite increasing evidence to inform women and clinicians about the medical benefits of a TOL versus ERCD, the rate of TOL attempts continue to decline.⁸ Nonmedical factors that influence the patterns and utilization of TOL after cesarean delivery are numerous, yet relatively little research has been devoted to acknowledging and understanding their influence on the patterns and utilization of TOL after prior cesarean delivery. Nonmedical factors that have been suggested to contribute to this decline include professional liability concerns, professional and institutional polices, patient insurance type, as well as provider and patient attitudes.^{35, 36}

Medical liability and provider decisionmaking. Examination of closed malpractice cases for obstetricians and midwives indicates that VBAC is an important cause of obstetric lawsuits for maternity providers.^37–40 According to a recent American College of Obstetricians and Gynecologists (ACOG) professional liability survey, 91 percent of obstetric and gynecologic physicians responding to the survey reported that they experienced at least one liability claim in their career and 62 percent of those claims related to obstetric care.³⁷ More than half of respondents reported making changes in their practice due to the availability or affordability of malpractice insurance with 19.5 percent reporting increasing their cesarean rate, 19.0 percent decreasing their VBAC rate, 21 percent decreasing their number of high-risk pregnant patients, and 6 percent stopping obstetric practice entirely.

Though the studies are few, the literature generally supports the association between medical-legal pressures and both increased likelihood to perform cesarean deliveries and reduced likelihood to perform VBACs.^{37, 41–43} Both regional and hospital malpractice claims have been associated with higher cesarean delivery rates. One study of hospitals in New York reported that the odds of cesarean delivery were three times higher in high premium regions compared with low premium regions (95 percent CI: 2.13 to 4.24).⁴¹ Similarly, higher hospital-level claims were significantly associated with higher cesarean rates after controlling for clinical risk (1.26; 95 percent CI: 1.10 to 1.43), and physicians’ perceptions of risk of suit was also associated with almost a two-fold increased odds of cesarean (1.96; 95 percent CI: 1.53 to 2.93). One study demonstrated that for each annual $10,000 increase in medical liability insurance premium, the primary cesarean rate increased by 15.7 per 1,000 for term nulliparous women.⁴² Looking specifically at tort reform, caps on noneconomic damages were the leading predictor of delivery method, in one study, with VBAC rates being significantly higher and cesarean delivery rates significantly lower in states where caps on noneconomic damages existed. A dose response of sorts was found among noneconomic tort caps suggesting that noneconomic caps at $250,000 would be associated with 9,000 additional VBACs and 12,000 fewer cesarean deliveries.⁴³ Overall the literature supports a connection between malpractice liability and even provider perception of risk of liability and use of cesarean.

Several studies have tried to understand providers’ attitudes toward TOL after a prior cesarean delivery.^44–49 These studies note disparity in the management approaches of providers in women who desire a TOL as well as a perceived increased risk of liability when caring for women who attempt a VBAC. Upon examination of 109 closed malpractice claims from a single liability insurer, Clark et al concluded that 80 percent of VBAC lawsuits were potentially avoidable by a management style that limited VBAC to spontaneously laboring women without repetitive moderate to severe variables.³⁹ Some authors have suggested checklists, structured guidelines, and simulation of obstetric emergencies to enhance consistency and reduce adverse events, but to date, there is insufficient evidence about their effectiveness.^50–52

More recently, reports of limited access to hospitals and providers willing to provide a TOL after a previous cesarean have emerged.²⁵ Much of this decline in VBAC services is thought to be in response to a shift in professional and hospital guidelines indicating that “VBAC should be attempted in institutions equipped to respond to emergencies with physicians immediately available to provide emergency care.”⁵³ Smaller hospitals with limited staff and resources have difficulty meeting these requirements, interpreted as in-house presence of obstetric surgical providers, and many institutions have discontinued offering VBAC services. Declines in rural hospitals offering TOL after cesarean have resulted in VBAC services becoming centralized, many times far away from where women live and work.⁵⁴ In a descriptive, comparative study, Misra et al found that VBAC attempts had declined in Maryland from 2000 to 2005 (4.65 versus 3.58 percent, respectively) while the total (primary and repeat) cesarean rate rose from 21.71 percent in 1995 to 24.03 percent in 2005.⁵⁵ In a study of all institutions (N=312) providing birth services in a four state region, Roberts et al found 30.6 percent of hospitals previously offering VBAC services prior to the 1999 ACOG policy recommendation had ceased doing so.⁵⁶ This study also found that access to VBAC services in smaller or more rural hospitals was disproportionately affected. The ethical, social, and financial implication of women delivering subsequent pregnancies by cesarean because of limited options for a TOL after cesarean delivery within their community is unstudied.

Several studies have explored the relationship between private and public health insurance and VBAC.^57–59 Wagner et al found that Medicaid insured women were more likely than privately insured women to attempt a TOL (64 versus 50 percent, p=0.001) and to have a VBAC (62 versus 60 percent, p=not significant [NS]).⁵⁸ In a recent review of state Medicaid coverage and utilization of cesarean delivery, Grant found that an increase in the amount physicians are reimbursed for cesarean deliveries versus vaginal delivery does account for a slight increase in the number of cesareans being performed.⁵⁹ Specifically, a $1,000 increase in the reimbursement for performing a cesarean increases cesarean delivery rates by 1 percent. A major factor that distinguishes VBAC from ERCD is the labor process that could take hours to days and requires constant provider supervision. The current structure for provider reimbursement reimburses the delivery event (e.g., vaginal versus cesarean delivery) rather than the process. No studies were found that addressed the effect of this structure of reimbursement on provider’s willingness to offer VBAC.

In summary, the nonmedical factors that influence the patterns and utilization of TOL after prior cesarean delivery are numerous and complex. Studies consistently suggest that these nonmedical factors play an important role in decisionmaking and patient access. A better understanding of nonmedical issues and the significance of their impact on utilization of VBAC is warranted.