Linking Evidence and Experience


Vaginal Birth After Cesarean Delivery

Current Status

 JAMA Vol. 287 No. 20,  May 22/29, 2002

Author Information <http://jama.ama-assn.org/issues/v287n20/rfull/#aainfo>
W. Benson Harer, Jr, MD, DHL
JCT10023
The dictum "Once a cesarean, always a cesarean" ruled for most of the 20th
century. 1 <http://jama.ama-assn.org/issues/v287n20/rfull/#r1>
Nevertheless, in the 1970s a small group of women who had prior cesarean
deliveries were eager to experience vaginal birth and risked a trial of
labor (a purposeful attempt to permit active labor development with
progression to vaginal delivery). 2
<http://jama.ama-assn.org/issues/v287n20/rfull/#r2>  Success in such cases
led the National Institutes of Health in 1981 to promote trial of labor for
patients who had previous cesarean deliveries. 2
<http://jama.ama-assn.org/issues/v287n20/rfull/#r2>
In 1981, the US rate of successful vaginal birth after a prior cesarean
delivery (VBAC) was only 3%, with the overall cesarean delivery rate of
17.9%. By 1997, the incidence of VBAC rose steadily to 27.4%. Despite this
dramatic increase in VBACs, the total US cesarean delivery rate rose to only
20.8% during the same time period ( Figure 1
<http://jama.ama-assn.org/issues/v287n20/fig_tab/jct10023_f1.html> ). 3
<http://jama.ama-assn.org/issues/v287n20/rfull/#r3> , 4
<http://jama.ama-assn.org/issues/v287n20/rfull/#r4>  The American College of
Obstetricians and Gynecologists (ACOG) stressed in 1984 5
<http://jama.ama-assn.org/issues/v287n20/rfull/#r5>  and 1995 6
<http://jama.ama-assn.org/issues/v287n20/rfull/#r6>  that VBAC should be
offered as an option to patients with fetuses in vertex presentations, with
1 or more low transverse uterine scars, and no known contraindication for
vaginal delivery. Informed consent for trial of labor and VBAC remained
necessary.
During the 1990s, managed care organizations identified VBAC as a way to
save money through shorter hospital stays and use of less costly resources.
Many such entities categorically demanded trial of labor in all cases. In
1993, Los Angeles County–University of Southern California Medical Center
adopted a policy requiring all women meeting ACOG criteria to attempt VBAC.
They calculated that each successful VBAC cost $2300 less than repeat
cesarean delivery. By 1997, the County of Los Angeles had paid $24 million
to settle 49 claims for adverse outcomes associated with VBAC. 7
<http://jama.ama-assn.org/issues/v287n20/rfull/#r7>  Millions more are
expected to be paid to provide lifetime care to children with brain injury
after labor complicated by uterine rupture. Denial of patient autonomy was
costly in both monetary value and human suffering, and the policy was
abandoned in 1995 in favor of informed patient choice.
The Los Angeles County–University of Southern California Medical Center
experience also showed that uterine rupture increased dramatically with the
number of prior cesarean deliveries. 8
<http://jama.ama-assn.org/issues/v287n20/rfull/#r8>  Such data led ACOG to
revise criteria in 1999 restricting VBAC attempts to patients with only 1 or
2 prior cesarean deliveries. 9
<http://jama.ama-assn.org/issues/v287n20/rfull/#r9>  A year later the ACOG
Task Force on Evaluation of Cesarean Delivery further restricted this to
only 1 prior low transverse cesarean delivery in a hospital setting with
capability for immediate response to a maternal or fetal emergency. The task
force report analyzed the extensive literature, which generated the current
recommendations and is recommended to readers desiring further information.
3 <http://jama.ama-assn.org/issues/v287n20/rfull/#r3>
The Los Angeles experience was mirrored nationwide as desired cost savings
from trial of labor and VBAC could not be demonstrated and cohort studies of
neonates born by VBAC and elective repeat cesarean delivery showed no
significant difference in fetal morbidity. 3
<http://jama.ama-assn.org/issues/v287n20/rfull/#r3> , 6
<http://jama.ama-assn.org/issues/v287n20/rfull/#r6>  In the current issue of
THE JOURNAL, Smith et al 10
<http://jama.ama-assn.org/issues/v287n20/rfull/#r10>  report the results of
a retrospective cohort study finding that the absolute risk of perinatal
death associated with trial of labor following cesarean delivery was low but
that the risk was significantly higher than that associated with planned
repeat cesarean delivery.
The ACOG bulletin noted that despite 800 citations in the literature, there
are no randomized controlled trials to show that maternal and neonatal
outcomes are better with VBAC than with repeat cesarean delivery. 9
<http://jama.ama-assn.org/issues/v287n20/rfull/#r9>  At present, there is no
hard evidence on the relative risks and benefits of term elective cesarean
delivery for nonmedical or nonobstetric reasons compared with vaginal
delivery. 11 <http://jama.ama-assn.org/issues/v287n20/rfull/#r11>
The most severe risk in trial of labor is uterine rupture, which occurs in
the range of 0.2% to 1.5% of attempted VBAC in patients who have a low
transverse uterine scar. 9
<http://jama.ama-assn.org/issues/v287n20/rfull/#r9>  Uterine rupture can be
a catastrophe in which immediate medical response is necessary to save the
life of both mother and fetus. Rupture is most likely in patients who had
classic (fundal) or other vertical incisions with prior cesarean deliveries
or uterine perforation during termination of a prior pregnancy. Low
transverse uterine scars are more likely to rupture if the patient has had
more than 1 prior cesarean delivery. Any condition that overdistends the
uterus can weaken the scar and increase risk, including multiple gestation,
polyhydramnios, or fetal macrosomia. The earliest sign of uterine rupture
usually is a fetal heart monitor tracing showing bradycardia, tachycardia,
or recurrent late decelerations, but change in abdominal configuration,
vaginal bleeding, or maternal hypovolemic shock may herald rupture. 3
<http://jama.ama-assn.org/issues/v287n20/rfull/#r3>  To enhance early
detection and intervention most obstetricians prefer continuous internal
monitoring of the fetal heart rate with one nurse for each patient
attempting trial of labor.
The ACOG recommendation for immediate response for a maternal or fetal
emergency has correctly been interpreted to mean that trial of labor or VBAC
should not be offered in level 1 or 2 maternity units that lack the
necessary teams of obstetrician, pediatrician, anesthesiologist, and support
staff in the hospital at all times. However, this may conflict with the
philosophy of a patient seeking a natural birth experience who wishes to
ambulate, delay or refuse intravenous fluids, and have only intermittent
external fetal auscultation instead of internal fetal heart rate monitoring.
This scenario is fraught with hazard in the event of uterine rupture as the
fetal heart rate pattern is usually one of steady and often rapid
deterioration with no early warning sign. Even 5 or 10 minutes' delay can
result in significant fetal harm. Nurse midwives and family practice
physicians may be more receptive to the natural birth philosophy but must
accept significant medical-legal liability risks if they offer patients
trial of labor and VBAC and cannot provide immediate, appropriate surgical
intervention in the case of maternal or fetal deterioration.



Current Standards



Current standards limit acceptable candidates for trial of labor and VBAC to
patients with only 1 prior low transverse scar, 37 to 40 weeks' gestation,
fetal vertex presentation, otherwise healthy pregnancy, and who are
monitored in a unit with capability to immediately respond to maternal and
fetal emergencies such as uterine rupture. 3
<http://jama.ama-assn.org/issues/v287n20/rfull/#r3>
Informed consent is essential for any patient who requests a trial of labor.
Extensive and witnessed discussion with the patients, and documentation of
this interchange, is crucial if there is liberalization of the above
criteria. This may include trial of labor in a patient who has had 2 or more
prior low transverse cesarean deliveries, an unknown or vertical uterine
scar, requested induction of labor, or preference to deliver in a unit where
time to respond to emergency might be 30 minutes or more with potentially
fatal consequences to mother, fetus, or both. Such situations are not
absolute contraindications, but require thoughtful individualized appraisal
of risks and benefits for the patient and fetus. The ultimate decision for
risk acceptance rests with the informed patient; physicians must also choose
their risk tolerance regarding availability of VBAC in their practice.
The trend is clearly to avoid formerly permissible situations for VBAC such
as multiple gestations, premature or postmature fetuses, possible fetal
macrosomia, and unknown uterine scar, all of which are associated with
increased incidence of uterine rupture. The risk of uterine rupture is also
significantly higher when labor is induced and particularly when a
prostaglandin is used during the induction process. 12
<http://jama.ama-assn.org/issues/v287n20/rfull/#r12>  Successful VBAC is
more likely in women who have had a prior successful vaginal delivery 13
<http://jama.ama-assn.org/issues/v287n20/rfull/#r13>  but many VBAC
candidates request repeat cesarean delivery to facilitate tubal ligation.
Vaginal birth after cesarean delivery has been promoted to decrease the
cesarean delivery rate. For any individual patient the risks of placenta
previa and placenta accreta increase progressively with each succeeding
cesarean delivery 14 <http://jama.ama-assn.org/issues/v287n20/rfull/#r14> ;
demographic shifts in developed nations show that many women now have only 1
or 2 children, minimizing this particular risk. 15
<http://jama.ama-assn.org/issues/v287n20/rfull/#r15>  Many women are
delaying pregnancy. In 1970, only 4% of primiparas were older than 30 years.
In 1994, that figure had increased to 21%. 3
<http://jama.ama-assn.org/issues/v287n20/rfull/#r3>  The rate of cesarean
delivery is significantly increased in women older than 30 years for many
reasons. Risks of cesarean deliveries appear to be as acceptable to many
women as the risks of vaginal birth, particularly operative vaginal
delivery. Urinary and fecal incontinence, pelvic organ prolapse, and sexual
dysfunction have an increased incidence following vaginal delivery. 16
<http://jama.ama-assn.org/issues/v287n20/rfull/#r16>  Sonographic studies
showed a 28% incidence of rectal sphincter damage in women who had visually
undamaged perineums after delivery. 17
<http://jama.ama-assn.org/issues/v287n20/rfull/#r17>  As this information
has entered the public domain, women are increasingly requesting both
primary and repeat cesarean deliveries. This is particularly true of VBAC
candidates who realize that the attempt may fail and result in a cesarean
delivery in 20% to 40% of trials of labor. 9
<http://jama.ama-assn.org/issues/v287n20/rfull/#r9>



Risks of Vaginal Delivery



A study of 583 000 births in California 18
<http://jama.ama-assn.org/issues/v287n20/rfull/#r18>  provides statistics of
intracranial hemorrhage in neonates. In mothers who had cesarean delivery
prior to initiation of labor, the rate of intracranial hemorrhage was the
lowest, 1 of 2750. When cesarean delivery was performed during labor, the
rate tripled to 1 of 907 and if it was done after a failed attempt to
deliver vaginally (by forceps or vacuum extraction), the incidence tripled
again to 1 of 334. The present increasing cesarean delivery rate reflects in
part a decline in operative deliveries by forceps and vacuum extraction
spurred by the perception of obstetricians that resorting to cesarean
delivery decreases liability because such statistics suggest modern cesarean
delivery may be safer than operative vaginal birth. 19
<http://jama.ama-assn.org/issues/v287n20/rfull/#r19>
The above statistics also reflect in part that fetal maturity can be
determined with a high degree of success in a patient who is monitored from
early pregnancy. This permits elective scheduling of a repeat cesarean
delivery. Alternatively, repeat cesarean delivery can be done at the first
signs of labor to minimize fetal risks associated with unanticipated
prematurity.
This enhanced safety of cesarean delivery is reflected in some international
statistics. Brazil has up to 80% cesarean delivery rate among private
insurance patients and about 50% to 60% overall. 20
<http://jama.ama-assn.org/issues/v287n20/rfull/#r20>  In these settings,
VBAC is almost nonexistent, which is a stark contrast to European countries
with VBAC rates of approximately 50%. 21
<http://jama.ama-assn.org/issues/v287n20/rfull/#r21>
Currently, there is no reliable method to select patients who will succeed
at VBAC. The International Federation of Gynecology and Obstetrics and ACOG
concur that the patient should make the decision to attempt VBAC after
thorough counseling of risks and benefits. 9
<http://jama.ama-assn.org/issues/v287n20/rfull/#r9> , 22
<http://jama.ama-assn.org/issues/v287n20/rfull/#r22>  Only the patient can
assess those relative values. Unfortunately, clear high-level scientific
evidence to guide the decision is lacking. Despite the increasing US
cesarean delivery rate, there is increasing demand for cesarean delivery by
women who must live with the consequences of adverse outcomes of trial of
labor or of traumatic vaginal births. The physicians who care for them on an
individual basis understand their concerns and their cumulative decisions
produce increasing rates for both primary and repeat cesarean deliveries. 23
<http://jama.ama-assn.org/issues/v287n20/rfull/#r23>
The situation has been further confused by the Joint Commission on
Accreditation of Healthcare Organizations (JCAHO) designation of VBAC rates
as 1 of 3 core measures of pregnancy care, which hospitals must report for
the ORYX program starting in July 2002. This JCAHO initiative collects data
for development of a nationwide database of performance measures. Many
hospital administrators, quality improvement managers, and obstetrical units
perceived this as a mandate to boost VBAC rates. In an effort to dispel that
incorrect perception, JCAHO sent a letter to all hospitals on December 6,
2001, explaining that "[t]his measure is configured as a neutral measure. Be
aware the Joint Commission does not intend to promote VBAC." 24
<http://jama.ama-assn.org/issues/v287n20/rfull/#r24>
This message must be understood so that maternity units not capable of
immediate emergency response will not allow women to attempt trial of labor
and VBAC under the mistaken belief that JCAHO expects these units to provide
VBAC service. Such units should not use VBAC as a core measure, but should
use the option to substitute a different measure appropriate to their actual
ranges of obstetrical care. In an unsafe setting VBACs might well be
perceived as a deficiency in obstetric care rather than a mark of
excellence.



Conclusion



The rise and incipient fall of VBAC exemplifies fundamental shifts in
medical care in the past 20 years. Previously, physicians made most medical
decisions; control then shifted to managed care dictates. Increasing
pressure by both physicians and the public is now shifting decisional
authority back to physicians and their patients. However, consumerism is
moving control of medical care increasingly into the hands of the patients
while physicians serve in more consultative and advisory roles. The current
status is thus a state of dynamic tension between women who want a natural
birth experience, women who want to avoid potential vaginal birth trauma,
entities promoting reduction of the cesarean delivery rate, and the
individual physicians who must care for each patient.
In 1997, an expert working group from the Department of Health and Human
Services established a 75th percentile target of 37% VBAC for suitable
candidates as then defined. 3
<http://jama.ama-assn.org/issues/v287n20/rfull/#r3>  The current shift of a
much more restricted cohort of carefully selected patients into the
exclusive domain of tertiary centers, coupled with increased patient
autonomy, will drive the national VBAC rate dramatically below that goal.



Author/Article Information


Author Affiliation: Department of Women's Health Care, Riverside County
Regional Medical Center, Moreno Valley, Calif.

Corresponding Author and Reprints: W. Benson Harer, Jr, MD, DHL, Department
of Women's Health Care, Riverside County Regional Medical Center, 26520
Cactus Ave, Moreno Valley, CA 92555 (e-mail: [log in to unmask]
<mailto:[log in to unmask]> ).

Contempo Updates Section Editor: Janet M. Torpy, MD, Fishbein Fellow.



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Edward E. Rylander, M.D.
Diplomat American Board of Family Practice.
Diplomat American Board of Palliative Medicine.