c-sections and vbacs – past, present, and future russell s. kirby, phd, ms, face professor and...
TRANSCRIPT
C-Sections and VBACs – Past, Present, and Future
Russell S. Kirby, PhD, MS, FACEProfessor and Vice Chair
Department of Maternal and Child HealthSchool 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
0.0
5.0
10.0
15.0
20.0
25.0
30.0
1989 1990 19911992 199319941995199619971998 19992000 2001 2002
Year
Per
cen
t o
f L
ive
Bir
ths
Total C- Section RatePrimary C-Section Rate
VBAC Rate
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 Rateby Race of Mother, 2001
United States Compared to Wisconsin and Alabama
US
Rate Rate State Rank Rate State Rank
Total C-Section Rate 24.4 19.1 45th highest 27.6 4th highest White Non-Hispanic 24.5 19.7 28.5 Black Non-Hispanic 25.9 16.9 26.8 Hispanic 23.6 18.4 21.5
VBAC Rate 16.4 23.0 43rd lowest 11.8 6th lowest White Non-Hispanic 16.8 22.3 11.0 Black Non-Hispanic 16.7 28.8 13.5 Hispanic 14.7 22.9 12.3
Wisconsin Alabama
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 Total
No. % No. % No. %
< 20 9 3.2 271 97.1 279 15
20 - 24.9 31 3.9 759 96.1 790 42
25 - 25.9 28 6.5 407 93.8 434 23
30 + 28 7.4 348 92.6 376 20
Total 96 5.1 1785 94.9 1881
Chi-Square (3 df) = 10.19, p<0.018
Univariate Odds of Cesarean Delivery, SSMC CNM Patients, 1994-98
Variable Odds Ratio 95 % C.I. p-value
Primigravida 1.53 1.02, 2.28 0.038
First Live Birth 2.69 1.75, 4.14 0.001
Married 0.83 0.38, 1.82 0.646
Maternal Race
Black 0.95 0.54, 1.69 0.871
White reference
Hispanic 0.90 0.34, 2.38 0.835
Other 0.71 0.09, 5.60 0.744
Univariate Odds of Cesarean Delivery, SSMC CNM Patients, 1994-98
Variable Odds Ratio 95 % C.I. p-value
Maternal Age
< 15 1.19 0.27, 5.17 0.815
15-17 1.36 0.75, 2.47 0.305
18-19 1.37 0.78, 2.40 0.275
20-24 reference
25-29 1.64 0.85, 3.15 0.142
30-34 1.15 0.39, 3.35 0.800
35+ 3.61 1.31, 9.93 0.013
Variable Odds Ratio 95 % C.I. p-value
Body Mass Index < 20 0.81 0.38, 1.73 0.591 20-24.9 reference
25-29.9 1.68 1.00, 2.85 0.052 30 + 1.97 1.16, 3.34 0.012Maternal Ht. <155 cm 2.45 1.41, 4.26 0.001Mother Smoked 0.75 0.43, 1.30 0.302
Univariate Odds of Cesarean Delivery, SSMC CNM Patients, 1994-98
Adjusted Odds of Cesarean Delivery, SSMC CNM Patients, 1994-1998
Characteristic Odds Ratio 95 % C.I. p-value
Obesity (BMI 30 +) 3.26 (1.60, 6.67) 0.0012Weight Gain > Recommended 2.09 (1.06, 4.11) 0.0326Short Stature (< 155 cm) 2.52 (1.12, 5.64) 0.0252No Previous Live Births 4.30 (1.78, 10.37) 0.0012Age 35 + 4.93 (1.08, 22.61) 0.0399Failure to Progress 60.42 (29.86, 122.24) 0.0001Breech Presentation 458.34 (133.74, 999) 0.0001Placental Abruption 82.56 (19.00, 358.67) 0.0001Fetal Distress 5.71 (2.58, 12.64) 0.0001Severe Pre-eclampsia 8.68 (1.09, 69.20) 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 double-suturing 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:
Adjusted Odd Ratio for Physician Vacuum/Forceps Use
Ph
ysic
ian
C S
ecti
on R
ate
3 02 82 62 42 22 01 81 61 41 21 086420
.3 0
.2 5
.2 0
.1 5
.1 0
.0 5
0 .0 0
Least Squares Regression: R2 =.23; F1,28 = 8.2 , p <.01
Figure 1 Relationship Between Physician Vacuum/Forceps Use and Cesarean Section Rates
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 EvidenceI: 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 case-control 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 Lydon-Rochelle 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 well-designed 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
0.0
5.0
10.0
15.0
20.0
25.0
30.0
19891990 199119921993199419951996199719981999 20002001 2002
Year
Per
cen
t o
f L
ive
Bir
ths
Total C- Section RatePrimary C-Section Rate
VBAC Rate
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?
