Uterine Rupture During Labor Among Women with Prior Cesarean Delivery

1
Uterine Rupture During Labor Among Women with
Prior Cesarean Delivery

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

2
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. 20013453-8.

3
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

4
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

5
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.
6
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.
7
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.
8
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.
9
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.
10
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?

11
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

12
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).

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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
  gt42wks.
• 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.

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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.

15
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

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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.

17
Assessing the Risk of TOL vs. C/S
18
Table 4. Complications of Rupture

• Women with uterine rupture were more likely than
  women without rupture to experience

• Anemia
• Infection
• Bladder injury
• Paralytic ileus

• Hysterectomy
• Maternal hospital stay gt 5 d
• Death of infant

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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).

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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

21
References Cited

• ACOG Practice Bulletin Vaginal Birth After
  Previous Cesarean Section. No. 5, July 1999.
• 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.
• Gabbe S. Obstetrics - Normal and Problem
  Pregnancies, 3rd ed., Churchill Livingstone, Inc.
  1996.
• Gregory KD, Korst LM, Cane P, Platt LD, Kahn K.
  Vaginal birth after cesarean and uterine rupture
  rates in California. Obstet Gynecol
  199994985-9.
• McMahon MJ, Luther ER, Bowes WA Jr, Olshan AF.
  Comparison of atrial of labor with an elective
  second cesarean section. N Engl J Med
  1996335689-95.
• Rageth JC, Juzi C, Grossenbacher H. Delivery
  after previous cesarean a risk evaluation.
  Obstet Gynecol 199993332-7.
• Ratcliffe SD, Baxley EG, Byrd JE, Sakornbut EL,
  eds. Family Practice Obstetrics. Philadelphia
  Hanley Belfus. 2001.