C-Sections and VBACs –
Past, Present, and Future
Russell S. Kirby, PhD, MS, FACE
Professor and Vice Chair
Department of Maternal and Child Health
School of Public Health
University of Alabama at Birmingham
Objectives
 Identify trends in Cesarean delivery and VBAC
 Discuss the clinical and public health
significance of recent trends
 Describe evidence-based practice and its role
in clinical decision making
 Review several recent influential publications
and their impact
 Speculate on the future of obstetrics and
labor/delivery management
Brief Summary for Those Who Are Knitting, Doing
Crossword Puzzles, or Discerning the Geometric
Pattern in the Carpeting
 Since the mid-1990s, both the total C-section rate and
the VBAC rate have risen dramatically, both nationally
and in Wisconsin.
 Although the reasons for these trends are many,
changes in clinical management, patient preferences,
and ‘defensive medicine’ all may be playing a role.
 These trends should be concerning from both the
clinical and public health perspectives.
 Hidden within the recent trends is a parable about the
practice of ‘evidence-based practice’.
Trends in Cesarean Deliveries and VBACs,
United States 1990-2002
30.0
Percent of Live Births
25.0
20.0
15.0
Total C- Section
Rate
10.0
Primary C-Section
Rate
5.0
VBAC Rate
0.0
1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002
Year
Trends
 The velocity of the increase in the primary
Cesarean section rate and the decline in
VBAC rates in the past three years is
unprecedented.
 In less than five years, more than ten years
of increasing VBAC rates has disappeared.
 Is this a good thing, or even a matter of
concern?
Is this a public health concern?
 Con: public health does not focus on clinical
management of patients. That is in the
responsibility of the health care system, peer
review, quality compliance, and provider
organizations.
 Pro: Cesarean section is among the most
common surgical procedures. It is more
expensive per total hospital stay than vaginal
delivery, and leads to more complications
and re-hospitalizations.
Is this a public health concern?
(continued)
 The Public Health Service has established
goals for the year 2010 promoting continued
reduction in overall Cesarean section rates
and increases in VBAC rates for the United
States.
– Objective 16-9a: Reduce C-S among low-risk
nulliparous women
– Objective 16-9b: Reduce C-S among women with
prior Cesarean birth
Where does Wisconsin fit in?
 Historically, Wisconsin has had one of
the lowest C-section rates in the US.
 In 1960, the rate was 4%, and from the
1970s on the C-section rate has tended to
be 25-33% lower than the national rate.
 Wisconsin has also been a leader in the
use of vaginal birth after Cesarean
section.
Total Cesarean Section Rate and VBAC Rate
by Race of Mother, 2001
United States Compared to Wisconsin and Alabama
US
Rate
Total C-Section Rate 24.4
Wisconsin
Rate State Rank
Alabama
Rate State Rank
27.6
28.5
26.8
21.5
4th highest
White Non-Hispanic 24.5
Black Non-Hispanic 25.9
Hispanic
23.6
19.1 45th highest
19.7
16.9
18.4
16.4
16.8
16.7
14.7
23.0 43rd lowest
22.3
28.8
22.9
11.8
11.0
13.5
12.3
6th lowest
VBAC Rate
White Non-Hispanic
Black Non-Hispanic
Hispanic
Risk Factors Associated with
Cesarean Delivery
 Many patient, health care system, and physician
characteristics are associated with higher or
lower rates of Cesarean section.
 A partial list includes maternal age (increased
risk), parity (decreased risk), obesity and short
stature (increased risk), estimated fetal weight >
4000g (increased risk), breech presentation
(increased risk), delivery in teaching hospital
(decreased risk), private insurance (increased
risk), fear of malpractice suits (greatly increased
risk).
Method of Delivery by Body Mass Index (BMI)
Sinai Samaritan CNM Patients, 1994-1998
BMI
Cesarean Vaginal
No. %
No. %
Total
No. %
< 20
20 - 24.9
25 - 25.9
30 +
Total
9
31
28
28
96
279
790
434
376
1881
3.2
3.9
6.5
7.4
5.1
271
759
407
348
1785
97.1
96.1
93.8
92.6
94.9
Chi-Square (3 df) = 10.19, p<0.018
15
42
23
20
Univariate Odds of Cesarean Delivery,
SSMC CNM Patients, 1994-98
Variable
Primigravida
First Live Birth
Married
Maternal Race
Black
White
Hispanic
Other
Odds Ratio
95 % C.I.
p-value
1.53
2.69
0.83
1.02, 2.28
1.75, 4.14
0.38, 1.82
0.038
0.001
0.646
0.95
0.54, 1.69
0.871
0.34, 2.38
0.09, 5.60
0.835
0.744
reference
0.90
0.71
Univariate Odds of Cesarean Delivery,
SSMC CNM Patients, 1994-98
Variable
Maternal Age
< 15
15-17
18-19
20-24
25-29
30-34
35+
Odds Ratio
95 % C.I.
p-value
1.19
1.36
1.37
0.27, 5.17
0.75, 2.47
0.78, 2.40
0.815
0.305
0.275
0.85, 3.15
0.39, 3.35
1.31, 9.93
0.142
0.800
0.013
reference
1.64
1.15
3.61
Univariate Odds of Cesarean Delivery,
SSMC CNM Patients, 1994-98
Variable
Odds Ratio
Body Mass Index
< 20
0.81
20-24.9
reference
25-29.9
1.68
30 +
1.97
Maternal Ht.
<155 cm
2.45
Mother Smoked 0.75
95 % C.I.
p-value
0.38, 1.73
0.591
1.00, 2.85
1.16, 3.34
0.052
0.012
1.41, 4.26
0.43, 1.30
0.001
0.302
Adjusted Odds of Cesarean Delivery,
SSMC CNM Patients, 1994-1998
Characteristic
Odds Ratio 95 % C.I. p-value
Obesity (BMI 30 +)
3.26
Weight Gain > Recommended 2.09
Short Stature (< 155 cm)
2.52
No Previous Live Births
4.30
Age 35 +
4.93
Failure to Progress
60.42
Breech Presentation
458.34
Placental Abruption
82.56
Fetal Distress
5.71
Severe Pre-eclampsia
8.68
(1.60, 6.67)
(1.06, 4.11)
(1.12, 5.64)
(1.78, 10.37)
(1.08, 22.61)
(29.86, 122.24)
(133.74, 999)
(19.00, 358.67)
(2.58, 12.64)
(1.09, 69.20)
0.0012
0.0326
0.0252
0.0012
0.0399
0.0001
0.0001
0.0001
0.0001
0.0412
Adjusted for race of mother (black), marital status,
primigravidity and very low birth weight.
Source: Kaiser and Kirby Ob Gyn 2001.
Clinical Documentation of
Previous Cesarean Section
 Most clinicians practice in settings that
do not have comprehensive, unified
clinical informatics applications.
 In a patient who’s previous delivery was
with another provider, how likely is it
that the patient’s history will document
the type of incision, the position of the
uterine scar, whether single- or doublesuturing was used, etc?
Are physicians who are more likely
to perform operative vaginal
deliveries more or less likely to
deliver by Cesarean section?
Answer: Yes, more likely
 Two studies demonstrate this convincingly:
 1) Sandmire and DeMott Am J Ob Gyn
1996;174:1557-64
 In a population-based study in Green Bay,
physicians who had lower C-S rates had lower
operative vaginal delivery rates.
 These physicians also had lower rates of use
of epidurals, and lower rates of induction.
 In contrast, they had higher rates of ambulation
during labor, and greater use of fetal heart rate
monitoring.
Operative Vaginal vs. C-Section Rates
(continued)
 2) Webb, Culhane, Tolosa 2003 (unpublished Mss)
 The method of delivery was analyzed for all
physicians with more than 100 deliveries in the
Philadelphia metropolitan area.
 The individual physician odds ratio for use of
vacuum/forceps was calculated, controlling for
patient demographic and reproductive health
characteristics.
 The odds ratios were plotted against the individual
physician C-section rate:
Figure 1 Relationship Between Physician
Physician C Section Rate
Vacuum/Forceps Use and Cesarean Section Rates
Least Squares Regression:
R2 =.23; F1,28 = 8.2 , p <.01
Adjusted Odd Ratio for Physician Vacuum/Forceps Use
The Realistic Evidence-Based Rating Scale
 Class 0: Things I believe
 Class 0a:Things I believe despite the available data
 Class 1: Randomized controlled clinical trials that
agree with what I believe
 Class 2: Other prospectively collected data
 Class 3: Expert opinion
 Class 4: Randomized controlled clinical trials that
don’t agree with what I believe
 Class 5: What you believe that I don’t
The Practice of Evidence-based Practice
 “integrating individual clinical expertise with
the best available external clinical evidence
from systematic research”
 individual clinical expertise: the proficiency
and judgment acquired through experience
and practice in clinical settings
 external clinical evidence: clinically relevant
research, from basic medical science and
patient-centered clinical research
How Do We Practice EBP?
 EBP is a life-long process of self-directed learning, in which
caring for patients creates for the clinician a need for
clinically important information about diagnosis, therapy,
prognosis, and other clinical and health services issues. In
this process, we:
– Convert information needs into answerable questions
(testable hypotheses)
– Track down the best evidence with which to answer them
– Critically appraise the evidence for validity and
usefulness
– Apply the results of this appraisal in clinical practice
– Evaluate performance
Why EBP?
 New types of evidence are being generated which, when
known and understood, have the potential to create
frequent and major changes in the way we care for our
patients
 Although we need this evidence daily, we usually fail to
get it
 Because of this, both our up-to-date knowledge and
clinical performance deteriorate over time
 Trying to remedy this personally through traditional
CME/CEU programs generally doesn’t improve clinical
performance
 A different approach to clinical learning has been shown
to keep its practitioners up-to-date. EBP is that different
approach.
Quality of Evidence
I:
Evidence obtained from at least one properly randomized
controlled trial.
II-1: Evidence obtained from well-designed controlled trials
without randomization.
II-2: Evidence obtained from well-designed cohort or casecontrol analytic studies, preferably from more than one center
or research group.
II-3: Evidence obtained from multiple time series with or
without the intervention. Dramatic results in uncontrolled
experiments (i.e. results of introduction of penicillin treatment
in 1940s) could also be regarded as this type of evidence.
III:
Opinions of well-respected authorities, based on clinical
experience; descriptive studies and case reports; or reports
of expert committees.
Key Publications Influencing Obstetrical
Management of Labor and Delivery
 Three publications in the past four years have
or will exert vast influence on physician
management of labor and delivery:
– Sachs BP, et al. NEJM 1999;340:54-57.
– Greene MF. NEJM 2001;345:54-55 (editorial
elaborating on Lydon-Rochelle M, et al. NEJM
2001;345:3-8.
– Minkoff H, Chervenak FA. NEJM 2003;348:946-50.
Sachs et al. on “The risks of lowering
the Cesarean-delivery rate”
 Argued that there is no basis for a national
public health goal targeting a C-section rate
of 15% (or any other level).
 Recommended that trials of labor not be
mandated for women with prior Cesarean
deliveries, and not be conducted at all in
facilities unable to perform emergency
Cesarean delivery.
Greene on “Vaginal delivery after
Cesarean section: is the risk acceptable?”
 Editorializes on Lydon-Rochelle et al.,
opining that the risks of uterine rupture
associated with VBAC are so great that
physicians should counsel all patients
with previous Cesareans concerning
these risks and obtain informed consent
before undergoing trial of labor.
 Do we have randomized studies on this
question?
A Look Inside
 Lydon-Rochelle et al. conducted a population-based,
retrospective study using linked hospital discharge
and vital statistics data.
 There are issues with documentation of risk factors
and outcomes in both vital statistics and hospital
discharge data.
 This study showed an increased risk for uterine
rupture with trial of labor, and even greater risks with
induction (in turn greater still with use of
prostaglandins).
 No data was presented concerning the location of the
uterine rupture in relation to the uterine scar.
What Level of Evidence Does
This Study Represent?
 Maybe II-2, or perhaps II-3
 Or perhaps, based on Greene’s editorial:
– Class 2: Other prospectively collected data or Class 3:
Expert opinion
 Does this study provide convincing evidence
sufficient to recommend against recommending
trial of labor? No – but it definitely argues against
the increased risks associated with induction
without or with prostaglandins for trial of labor.
 There may be a cautionary tale in the LydonRochelle paper, but it is not a blanket injunction
against VBACs.
Minkoff and Chervenak on “Elective
primary Cesarean delivery”
 Reviews history of this concept since 1985.
 Describes risks and benefits of elective primary
Cesareans for both mother and fetus.
 Does not perform either a systematic review or a
meta-analysis.
 Summarizes the research literature (without any
documentation to substantiate the statement):
– “Unfortunately, the interpretation of many of the
relevant studies on the subject is limited by their
designs and by conclusions that sometimes
conflict.”
Minkoff and Chervenak on “Elective
primary Cesarean delivery” (continued)
 Concludes with the following statement:
– “Although the evidence does not support the
routine recommendation of elective cesarean
delivery, we believe that it does support a
physician’s decision to accede to an informed
patient’s request for such a delivery”.
– NEJM 2003 Mar 6;348:949.
Commentary on Elective Cesareans
“That women are seeking elective cesarean
deliveries is probably more significant in that it
indicates failures of modern medicine and society at
large in the sense that women may fear the
experience of labor, and birth attendants may fear
the legal risks of allowing appropriate women to have
a trial of labor. Modern management of labor should
be reassessed to address the concerns raised by
proponents of elective cesarean delivery. If elective
cesarean delivery becomes an acceptable
alternative, we may never be able to undo the
practice.”
How do these influential
publications rate in terms of EBP?
 Do any of them provide systematic
reviews or meta-analytic summaries
of the evidence?
 Are they based on randomized
controlled clinical trials? Or welldesigned multi-center cohort or
case-control studies?
 Are they based on ‘expert’ opinion?
Evidence-based Malpractice
 Perhaps these studies are the leading edge of a
new phenomenon in clinical care: Evidence-based
Malpractice.
 Practitioners of EBP sometimes forget the criteria
for making clinical decisions, but none of the
proponents of EBP would ever recommend that
editorials and commentaries by influential
physicians should form the basis for sea changes
in clinical management.
 And yet, in the case of C-sections and VBACs,
this appears to be what has happened in the US in
the past four years.
Trends in Cesarean Deliveries and VBACs,
United States 1990-2002
Percent of Live Births
30.0
25.0
20.0
15.0
Total C- Section
Rate
Primary C-Section
Rate
10.0
5.0
VBAC Rate
0.0
1989 1990 19911992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002
Year
What does the future hold?
 Will rates of primary C-section rise
dramatically in the coming years?
 Will any obstetricians be willing to permit
women with previous Cesarean delivery to
undergo trial of labor?
 Will anyone care?
Questions or thoughts?
rkirby@uab.edu
205-934-2985