The rise in cesarean delivery has led to increasing numbers of women who must subsequently choose between a trial of labor after cesarean delivery (TOLAC) or repeat cesarean delivery. Usually the result is repeat cesarean delivery based not solely on the woman's choice, but on availability of health care providers and facilities that offer TOLAC. The rate of vaginal birth after cesarean delivery (VBAC) in the United States decreased from 28.3% in 19961 to approximately 8% in 2006,2 contributing to a rise in overall cesarean delivery rates from 20.7% in 19962 to 32.8% in 2010.3 The decrease in VBAC has occurred because fewer women attempt TOLAC,4 because the rate of vaginal birth for women choosing TOLAC has remained stable over time at approximately 75%.
What changes caused so many fewer women to attempt VBAC? In March 2010, a National Institutes of Health Consensus Development Conference called for research to examine the factors causing the decline in TOLAC.5 The conference recommended that the American College of Obstetricians and Gynecologists (the College) and the American Society of Anesthesiologists reassess the College’s recommendation that TOLAC only be offered in “hospitals fully equipped to immediately provide emergency care,”6 interpreted by most sites as requiring the presence of an in-house surgical team and anesthesia personnel during TOLAC.7 Most rural and many urban hospitals do not offer TOLAC services.8,9 Explanations include lack of in-house obstetric surgeons or anesthesia personnel, higher malpractice rates for physicians and hospital, and health care provider and patient preference for repeat cesarean delivery.5,8,9
Similar to other states, the New Mexico VBAC rate decreased from 36.9% to 12% from 1996 to 2006.2,10 The primary aim of this study was to examine the change in TOLAC access in New Mexico's rural hospital maternity units from 1998 to 2012 and to identify barriers to TOLAC services. Secondary aims were to examine the emergency cesarean delivery response times and presence of on-site surgeons and anesthesia personnel. We also sought to examine whether New Mexico's maternity care providers would support statewide TOLAC clinical guidelines.11
MATERIALS AND METHODS
The directors of each hospital maternity unit in New Mexico were surveyed in 2003 to determine the availability of TOLAC in 1998 and 2003. Follow-up surveys were conducted in 2008 and 2012 to determine whether availability of TOLAC in each hospital changed since the last survey. In a second phase of the study, in 2008, a confidential survey was mailed out to obstetrician–gynecologists (ob-gyns), family medicine physicians, and certified nurse-midwives providing hospital-based maternity care in New Mexico. Maternity care providers were identified from mailing lists obtained from the New Mexico sections or chapters of the American Congress of Obstetricians and Gynecologists, the American Academy of Family Physicians, and the American College of Certified Nurse-Midwives. Maternity care providers who were not currently offering labor and delivery-based maternity care services were excluded from the study. The 31-question maternity care provider survey included demographic characteristics, practices and barriers related to TOLAC, the number of annual hospital births, and maternity care providers' opinions about their hospitals' resources for providing TOLAC and emergency cesarean deliveries.
“Urban hospitals” were those located in Bernalillo County (Albuquerque), Dona Ana County (Las Cruces), and Santa Fe County (Santa Fe); hospitals in all other counties were considered rural. Level III neonatal intensive care units and inpatient maternal–fetal medicine consultation in New Mexico are available only in Albuquerque hospitals. The maternity care provider survey included a question about usual response time to assemble an operating room team (physician, surgical technician, anesthesia personnel, and nursing staff) for a “true” emergency cesarean delivery (ie, cord prolapse, bradycardia, abruption, or uterine rupture) and included responses “within 20 minutes,” “21–30 minutes,” or “more than 30 minutes.” For maternity care providers working in hospitals without either an in-house obstetric surgeon or anesthesia provider, the survey included separate questions regarding the times for arrival of the obstetric surgeon and anesthesia personnel using the same response time categories as for the full operating room team. Thirty minutes represents the traditional acceptable time limit from decision to initiation for an emergency cesarean delivery; however, current recommendations from the College’s Guidelines for Perinatal Care are to individualize the response time based on the maternal and fetal risks of the particular clinical situation.12 We chose “within 20 minutes” as the shorter time interval based on two studies13,14 demonstrating excellent neonatal outcomes in the setting of uterine rupture with an 18-minute or less time period from decision to emergency cesarean delivery.
Survey completion reminders for the maternity care provider survey included telephone calls, e-mails, and mailed postcards. Confidentiality was preserved because responses were sent back in envelopes without return addresses. Surveys were identifiable only by the research number on the written or electronic survey. The University of New Mexico human research review committee approved the study.
Survey data were entered in electronic format15 and analyzed using SAS 9.1 software.16 Pearson χ2 and Fisher’s exact test or the Freeman-Halton extension of Fisher’s exact test was used for categorical analysis to identify differences among specialties and health care providers in rural and urban settings. Before initiating the study, statistical power for dichotomous variables such as perceived barriers was calculated assuming sample sizes of 50 for each specialty and equally spaced proportions averaging 0.50 among the three specialties. There is at least 80% power at an α of 0.05 if the spread among specialties is 0.34, 0.50, and 0.66 or larger. There is also at least 80% power at an α of 0.05 for the urban and rural comparison if the proportions are 0.38 and 0.62.
Of New Mexico's 33 counties, 22 (66.7%) had maternity care units from 2003 to 2012. All maternity unit directors responded to the questionnaires about availability of TOLAC at each of the four time points (1998, 2003, 2008, and 2012). The proportion of New Mexico counties with TOLAC available within the county had decreased 68% from 1998 to 2008. In 1998, all 22 counties with inpatient maternity units had TOLAC available within the county (Fig. 1). By 2003, only 13 of 22 (59.1%) counties had inpatient maternity care units with TOLAC access within the county. In 2008, TOLAC was available in only seven of the 22 counties (31.8%). As of 2012, TOLAC was available in two additional counties (9/22 [40.9%]).
The 2008 maternity care provider survey was completed by 89% of certified nurse-midwives, 92% of family medicine physicians, and 78% of ob-gyns for an overall response rate of 85.5% (206/241). Family medicine physicians were evenly distributed in urban and rural sites, whereas the majority of certified nurse-midwives and ob-gyns practiced in urban sites (Table 1). A majority of rural maternity providers (55.4%) serve at hospitals with 500 or fewer deliveries per year (Table 1). In 2008, nearly 90% of urban maternity care providers offered TOLAC services compared with fewer than half of rural health care providers (P<.001) (Table 2). Few rural maternity units have 24-hour in-house obstetric surgeons or anesthesia personnel; thus, the time to provide a cesarean delivery was longer in rural hospitals (Tables 2 and 3).
Seventy-nine percent of rural health care providers (n=69) reported the ability to assemble a full operative team within 30 minutes (Table 2). Of the 57 maternity providers in rural hospitals not offering TOLAC, 73% estimated a timeframe of 20 minutes or shorter for the presence of an obstetric surgeon, although only 43% estimated that an anesthesia provider could be available in the same timeframe (P<.001). Eighty-five percent of these health care providers indicated an obstetric surgeon could be available for cesarean delivery within 30 minutes, but only 70% indicated an anesthesia provider was available within the same timeframe (P=.008). All the maternity care providers based in facilities that could have an anesthesia provider in either the 20-minute or 30-minute timeframe were also able to have an obstetric surgeon in the specified time.
New Mexico maternity providers in hospitals without TOLAC identified anesthesia availability (88%), hospital policy (80%), medical malpractice policies (80%), malpractice cost (69%), and obstetric surgeon availability (59%) as the primary barriers to TOLAC access (Table 3). Family medicine physicians were more likely to report lack of an obstetric surgeon as a barrier than certified nurse-midwives and ob-gyns (P<.012) (Table 3). Ob-gyns and certified nurse-midwives were more likely than family medicine physicians to list malpractice concerns as a barrier (P<.012). A greater proportion of rural and urban family medicine physicians (33/60 [55%]) and rural maternity providers (36/74 [49%]) is covered by the Federal Tort Claims Act (P<.001), which provides liability coverage to health care providers at federally qualified health centers and Indian Health Service facilities. For urban and certified nurse-midwives and ob-gyn providers, employer or practice group purchase of malpractice insurance predominated with few using Federal Tort Claims Act (10% urban, 10% certified nurse-midwives, 12% ob-gyns).
Patient and health care provider preference were uncommonly reported as a barrier to offering TOLAC. Two thirds of all maternity care providers estimated that more than 40% of their eligible patients would choose TOLAC if available. More than 85% of all maternity care providers (certified nurse-midwives and family medicine 93% each and ob-gyns 86%) indicated they would offer TOLAC if the hospital was supportive and malpractice insurance covered TOLAC. Certified nurse-midwives (100%) and family medicine physicians (76%) were more likely than ob-gyns (47%) to consider statewide clinical guidelines useful in reducing malpractice risk and increasing TOLAC access (P<.02).
The availability of TOLAC in New Mexico diminished over the past decade with a slight increase in 2012 compared with 2008. The primary barriers reported by maternity care providers were lack of in-hospital personnel and hospital policies prohibiting TOLAC with few interspecialty differences in perceived barriers. The reduction in TOLAC availability appears most likely the result of inability to comply with the College’s “immediate availability” standard.
When rural hospitals discontinue TOLAC services, women face difficult choices: schedule a repeat cesarean delivery, move in late pregnancy to an area with a hospital offering TOLAC, or assume the risk of traveling in labor to access TOLAC services. Our study suggests that rural New Mexico women desiring TOLAC but lacking the ability to relocate to another hospital must plan a repeat cesarean delivery.
With fewer TOLAC attempts, more women experience multiple cesarean deliveries with a concomitant increase in the incidence of placenta previa and accreta,17 surgical complications, and other maternal morbidity.4,18–20 The incidence of placenta previa in New Mexico increased from 3.7 cases per 1,000 births (n=371) in 2003–2007 to 6.8 cases per 1,000 births (n=687) in 2008–2011 according to the New Mexico State Inpatient Discharge data set. Some women who strongly desire TOLAC may choose home birth, an option that may lead to catastrophic uterine rupture in a far riskier setting than that of a rural hospital unable to meet the “immediate availability” guideline.21 Although uncommon, the incidence of home VBAC in the United States increased by almost 50% from 2003 to 2008.22
Strengths of our study include 100% participation of New Mexico hospital-based maternity units and a high response rate from all three maternity care provider groups. Selection bias could occur if the maternity care providers' decision to complete the survey was affected by their attitudes toward TOLAC; the high response rate makes it unlikely that selection bias influenced our results. The small number of maternity care providers practicing in hospitals without TOLAC services limited the statistical power to identify differences in barriers reported by different health care provider groups. The large proportion of family medicine maternity care providers covered by the Federal Tort Claims Act (mainly Indian Health Service units) may limit applicability of these results to other practice settings.
The restriction of maternal choice of TOLAC and the downstream effects of multiple repeat cesarean deliveries led the National Institutes of Health consensus conference to advocate for increased access to TOLAC. The College’s guideline recommendations for women desiring TOLAC who live in areas without TOLAC services included referral to a facility offering TOLAC, creation of regional referral centers, or an understanding that increased medical risk is incurred when attempting vaginal birth at hospitals that do not have immediate availability of a surgical team. The College’s practice guideline acknowledges that.
“In areas with fewer deliveries and greater distances between delivery sites, organizing transfers or accessing referral centers may be untenable. Respect for patient autonomy supports the concept that patients should be allowed to accept increased levels of risk, however, patients should be clearly informed of such potential increase in risk and management alternatives.”7
Many New Mexico hospitals fit this “untenable” description. The average distance from the 19 hospitals whose maternity care units did not offer TOLAC in 2008 to hospitals offering TOLAC was 121 miles. Only eight of the hospitals were within 100 miles of a unit offering TOLAC and none were within 35 miles. Most New Mexico maternity care providers without TOLAC access serve at units that can provide emergency cesarean delivery within 20–30 minutes, the usual recommended timeframe for initiating an emergency cesarean delivery. The overall rate of emergency cesarean delivery for all indications other than uterine rupture (ie, cord prolapse, placental abruption, or fetal bradycardia) is far greater than that for uterine rupture.23 Increased availability of TOLAC in these units with informed patient consent should be encouraged.
The availability of anesthesiologists or certified registered nurse anesthetists in rural maternity care units is a limiting factor nationwide; anesthesia workforce estimates indicate that a requirement for in-house anesthesia personnel is not practical from staffing and financial perspectives.24 The development of local or regional guidelines may increase TOLAC availability; a systematic review demonstrated a greater effect of regional than national guidelines on increasing VBAC rates.25 The Vermont/New Hampshire vaginal birth after cesarean delivery project of the Northern New England Perinatal Quality Improvement Network created a local definition of “immediately available,” developed patient education materials discussing risks and benefits of TOLAC, and acknowledged the difference in resources between community and level III hospitals.11 Risk stratification determined the appropriateness of caring for women in hospitals with varying resources. In-house anesthesia was not required for “low-risk” patients undergoing TOLAC.11 Most New Mexico maternity care providers indicated willingness to undertake TOLAC services if guidelines were developed to address perceived medicolegal risk and hospital policy restrictions.
Despite the well-documented increased risk from repeat cesarean delivery and the National Institutes of Health recommendations to increase availability of TOLAC, many women in New Mexico may not be able to choose an attempt at vaginal birth after a prior cesarean delivery. Maternity care providers, hospital administrators, and public health planners should identify strategies to afford all women the option to attempt a vaginal birth. Providing such opportunities respects women's choices and may improve long-term obstetric outcomes.
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