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Uterine Rupture During Labor Among Women with Prior Cesarean Delivery

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					Uterine Rupture During Labor Among
Women with Prior Cesarean Delivery


       Michael Mendoza, MD, MPH
       Evidence Based Medicine Clerkship
                 August 2001
Overview

Vaginal Birth After Cesarean (VBAC)
   History
   Advantages and Disadvantages
   Current Practice as of 1999 ACOG Guidelines


Lydon-Rochelle, M, Holt VL et al. Risk of Uterine
Rupture During Labor Among Women with Prior
Cesarean Delivery. New England Journal of
Medicine. 2001;345:3-8.
History of VBAC

1900: “Once a cesarean, always a cesarean.”3
1981: NICHD Conference on Child Birth
concluded that vaginal delivery after cesarean
birth is an appropriate option.3
1987: Still more than 90 percent of women with
a prior cesarean delivery had a repeat
procedure.3
Recent History of VBAC

Limited studies
   Nova Scotia, Canada (1996): Too few women in
    sample to detect rare event.5
   Switzerland (1999) and California (1999):
    Demonstrated higher risk of uterine rupture in
    VBAC but did not account for obvious biases. 4,6
Still no randomized trials comparing neonatal
and maternal outcomes in VBAC vs. repeat
C/S…
Advantages of VBAC7

Lower risk of infection
Shorter hospital stays
Lower overall delivery costs
Opportunity to experience family-centered
birthing
More rapid recovery
Lower morbidity for mother and baby
Fewer blood transfusions
Lower overall mortality rate
  Ratcliffe SD, Baxley EG, Byrd JE, Sakornbut EL, eds. Family Practice Obstetrics. Philadelphia: Hanley & Belfus. 2001.
Disadvantages of VBAC7

Increased risk of uterine rupture (therefore
increased risk of hysterectomy)
Maternal fever
Cesarean delivery may still be required
Possibility of serious perineal lacerations
Maternal frustration and anger
VBAC cannot be scheduled in advance


  Ratcliffe SD, Baxley EG, Byrd JE, Sakornbut EL, eds. Family Practice Obstetrics. Philadelphia: Hanley & Belfus. 2001.
Current Practice

Recommendations based on good and
consistent evidence
   Most women with one previous cesarean delivery
    with a low-transverse incision are candidates for
    VBAC, should be counseled about VBAC, and
    should be offered a TOL.
   A previous uterine incision extending into the
    fundus is a contraindication for VBAC.


                  ACOG Practice Bulletin: Vaginal Birth After Previous Cesarean Section. No. 5, July 1999.
Current Practice (cont.)

Recommendations based on limited or
inconsistent evidence
   Women with two previous low-transverse
    cesarean deliveries and no contraindications who
    wish to attempt VBAC may be allowed a TOL.
   Use of oxytocin or prostaglandin gel for VBAC
    requires close patient monitoring
   Women with a vertical incision within the lower
    uterine segment that does not extend into the
    fundus are candidates for VBAC.
                  ACOG Practice Bulletin: Vaginal Birth After Previous Cesarean Section. No. 5, July 1999.
Current Practice (cont.)

Recommendations based primarily on
consensus and opinion
   VBAC should be attempted in institutions
    equipped to respond to emergencies with
    physicians immediately available to provide
    emergency care




                  ACOG Practice Bulletin: Vaginal Birth After Previous Cesarean Section. No. 5, July 1999.
The Research Question…

              Is the risk of uterine
              rupture among post-
              cesarean women who
              under go a spontaneous
              or induced trial of labor
              significantly higher than
              those who deliver by
              repeat cesarean without
              trial of labor?
Methods: Study Design

Population-based
retrospective cohort study
   Advantages: can detect rare
    outcomes (e.g., uterine
    rupture) in a study over longer
    duration, cheaper than
    prospective cohort studies,
    less subject to bias
   Disadvantages: limited to
    available dataset (may not
    have data on desired
    characteristics), dataset may
    be incomplete, possibility for
    improper coding into dataset
Methods: Sample Characteristics

              All primiparous women who
              gave birth to singleton infants
              by cesarean section in civilian
              hospitals in Washington State
              from 1/1/87 to 12/31/96 AND
              who delivered a singleton
              infant during the same period.
              Initial cohort: 20,525 (430
              excluded who had a second
              delivery before 1989 when
              “repeat cesarean no labor” was
              added to birth certificates).
Table 1. Demographics

At the time of second delivery, women with
spontaneous onset of labor and repeat cesarean were
similar with respect to demographic and perinatal
characteristics.
Women who underwent induction without PG were
more likely than women without TOL to deliver EGA
>42wks.
Women who got PG were less likely to deliver within
two years of their first deliver AND more likely to deliver
at a level II hospital than women without TOL.
Table 2. Perinatal Characteristics

The frequency of medical conditions and
complications of pregnancy differed:
   Women who had spontaneous labor were
    significantly less likely than women with no trial of
    labor to have DM, HTN, preeclampsia, breech,
    HSV, placenta previa.
   Women with induction without PG were less likely
    than women who did not undergo TOL to have
    breech, HSV, or placenta previa.
   Women with PG induction were significantly less
    likely to have breech or HSV than women who did
    not TOL.
Results: Rate of Uterine Rupture

                Repeated C/S without
                labor: 1.6 / 1000
                Spontaneous onset of
                labor: 5.2 / 1000
                Induction of labor
                without PG: 7.7 / 1000
                Induction of labor with
                PG: 24.5 / 1000
  Table 3. Relative Risk: C/S vs. TOL

A greater relative
risk (RR) was
observed among
women induced
without PG, and
an even greater
RR was observed
among those
induced with PG.
    Assessing the Risk of TOL vs. C/S

                               Absolute                                 Number
                                                             Relative
                 Incidence       Risk        Relative Risk              Needed
                                                               Risk
                 (per 1000)    Increase        (95% CI)                 to Harm
                                                             Increase
                              (per 1000)                                 (1/ARI)


 Repeat C/S
  (no TOL)         1.6           --              1.0           --          --

Spontaneous
onset of labor     5.2          3.6         3.3 (1.8-6.0)     2.3        277

 Induction
 without PG        7.7          6.1         4.9 (2.4-9.7)     3.9        165

  Induction
   with PG         24.5         22.9       15.6 (8.1-30.0)    14.6        43
Table 4. Complications of Rupture

Women with uterine rupture were more
likely than women without rupture to
experience:
   Anemia               Hysterectomy
   Infection            Maternal hospital
   Bladder injury        stay > 5 d
   Paralytic ileus      Death of infant
Conclusions

Trial of labor (of any kind) in women with prior
cesarean was associated with at least a three-fold
increase in risk of uterine rupture, but risk of rupture
remains low.
Even when controlling for preexisting medical
conditions or complications of pregnancy, results
were similar.
Even though induction with PG is associated with
greater risk of uterine rupture, the nature of this
association is unclear (i.e. it may be dose-
dependent).
Assessing the Validity of this Study

Internal Validity
   Bias?
External Validity
 Will this change my practice?
 CHN patients unlikely to match
  demographic characteristics of Washington
  State
     References Cited
1.   ACOG Practice Bulletin: Vaginal Birth After Previous Cesarean Section. No. 5,
     July 1999.
2.   Cesarean Childbirth: Report of a Consensus Development Conference
     Sponsored by the National Institute of Child Health and Human Development.
     DHHS Pub. No. 82-2067. Government Printing Office, Washington, DC,
     October 1981.
3.   Gabbe S. Obstetrics - Normal and Problem Pregnancies, 3rd ed., Churchill
     Livingstone, Inc. 1996.
4.   Gregory KD, Korst LM, Cane P, Platt LD, Kahn K. Vaginal birth after
     cesarean and uterine rupture rates in California. Obstet Gynecol
     1999;94:985-9.
5.   McMahon MJ, Luther ER, Bowes WA Jr, Olshan AF. Comparison of atrial of
     labor with an elective second cesarean section. N Engl J Med 1996;335:689-
     95.
6.   Rageth JC, Juzi C, Grossenbacher H. Delivery after previous cesarean: a risk
     evaluation. Obstet Gynecol 1999;93:332-7.
7.   Ratcliffe SD, Baxley EG, Byrd JE, Sakornbut EL, eds. Family Practice
     Obstetrics. Philadelphia: Hanley & Belfus. 2001.

				
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