Williams ch.26 Prior Cesarean Delivery

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Williams ch.26Prior Cesarean Delivery

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• For many decades, a scarred uterus was believed
  to contraindicate labor out of fear of uterine
  rupture
• Cragin (1916)
• Once a cesarean, always a cesarean
• When this statement was made, the classical
  vertical uterine incision was used almost
  universally
• The ACOG (1998)
• In the absence of a contraindication, a woman
  with one previous low-transverse cesarean
  delivery be counseled to attempt labor in a
  subsequent pregnancy
• VBAC
• Vaginal birth after cesarean
• Pronounced Vee back

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• Trial of labor versus repeat cesarean delivery
• Candidates for a trial of labor
• Labor and delivery considerations
• Uterine rupture

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Trial of labor versus repeat cesarean delivery
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Risks and benefits

• Beginning in 1989, VBAC increased,
• A number of reports that suggested that
• VBAC might be riskier than anticipated
• Scott (1991) 12 uterine rupture
• Two women hysterectomy
• Three perinatal death
• Two infants long-term neurological impairment
• Porter and colleages (1998) 26 uterine rupture
• 23 of the infants were dead or damaged
  (intrapartum asphyxia)
• Fewer women with a prior cesarean incision
  attempting vaginal delivery
• -gt increased cesarean delivery rate

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Magnitude of risk

• Although uterine rupture and its complications
  clearly are increased with a trial of labor,
• -gt The absolute risk of complications is quite
  low
• These factors should weigh only minimally in the
  decision to attempt VBAC
• The absolute risk of uterine rupture resulting in
  death or injury to the fetus about 1 per 1000
• The major controversy surrounding the management
  thus stems from the question
• Is a 1 per 1000 risk of having an otherwise
  healthy
• fetus die or be damaged as a result of a
  trial of
• labor acceptable ?

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Maternal morbidity

• Maternal mortality not appear to differ
  significantly compared with an elective repeat
  cesarean
• Maternal morbidity conflicting result
• In 2000, Mozurkewich and Hutton
• about half required a blood transfusion or
  hysterectomy
• compared with an elective repeat cesarean
• In 2004, Landon
• the risks of transfusion and infection were
  significantly
• greater for a trial of labor
• In 1996, McMahon
• the major complication (hysterectomy,
  uterine rupture,
• operative injury) were twice as common in a
  trial of labor
• fivefold greater at a vaginal delivery
  failed

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Costs

• Grobman (2000), cohort of 100,000
• The safety of VBAC as well as cost effectiveness
• Routine repeat cesarean for a second birth was
  calculated to result in an increased cost of
  179million
• DiMaio (2002)
• Nearly 1100 higher for each elective repeat
  cesarean
• Clark (2000)
• The cost of long-term care for neurologically
  injured infants is taken into account, trial of
  labor is unlikely to be associated with a
  significant cost saving for the health care
  system

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Elective repeat cesarean delivery

• Preference
• In spite of increased risks (anesthesia,
  hemorrhage, damage to the bladder and other
  organs, pelvic infection, scarring), an elective
  repeat cesarean is considered to be preferable to
  attempting a trial of labor
• Frequent reasons
• ? the convenience of a scheduled delivery
• ? the fear of a prolonged and potentially
  dangerous labor
• Abitbol (1993)
• 312 women studied, 125(40) opted for a repeat
  cesarean
• No complications in the elective cesarean group
• Two unanticipated fetal deaths in the VBAC
  group
• ? Scheduled cesarean 93 were satisfied with
  their choice
• ? Elected a trial of labor only 53
• ? Uncomplicated trial of labor 80

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Elective repeat cesarean delivery

• Fetal maturity
• If elective repeat cesarean delivery is planned,
  it is essential that the fetus be mature

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Candidates for a trial of labor
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Type of prior uterine incision
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Type of prior uterine incision

• The lowest risk of scar separation
• the lower uterine segment transverse scar
• The highest rates of rupture
• the classical incision (extending into the
  fundus)
• In about one third classical incision, the scar
  will rupture before the on set of labor
• Not infrequently, rupture may take place several
  weeks before term
• With uterine malformations, the risks for uterine
  rupture as high as with a classical incision
• In 1999, Ravasia
• 8 rupture with unicornuate, bicornuate,
  didelphic, septate uterus

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Type of prior uterine incision

• A prior vertical incision that did not extend
  into the fundus the risk of uterine rupture is
  controversial
• Martin and Shipp (1997)
• low-vertical uterine incision did not have an
  increased risk for rupture
• The ACOG (2004)
• low-vertical incision without fundal
  extension may be candidates for VBAC
• Previously sustained a uterine rupture are at
  increased risk for recurrence
• A rupture confined to the lower segment 6
  recurrence risk
• Prior rupture included the upper uterus 32
  recurrence risk

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Closure of prior incision

• Whether the risk of subsequent uterine rupture is
  related to the number of layers is controversial
• Chapman (1997), Tucker (1993)
• no relationship between a one-and two-layer
  closure and risk of subsequent uterine rupture
• Durnwald and Mercer (2003)
• single layer closure -gt no increased risk of
  rupture, uterine dehiscence
• Bujold (2002)
• single layer closure -gt a fourfold increased
  risk of rupture compared with a double layer
  closure
• Videaff and Lucas (2003)
• double layer closure -gt wound healing have
  not demonstrated any advantages

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Closure of prior incision

• Healing of the cesarean incision
• Willians (1921)
• By regeneration of the muscular fibers and
• not by development of scar tissue
• Inspection of the unopened uterus at repeat
  c/sec
• -gt no trace of the former incision
• -gt almost invisible linear scar
• Schwarz (1938)
• By fibroblast proliferation
• the proliferation of connective tissue is
  minimal,
• -gt the normal relation of smooth muscle to
• connective tissue gradually is
  reestablished

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Interdelivery interval

• If the hysterotomy scar did not have sufficient
  time to heal
• -gt The risk of uterine rupture would be
  increased
• Completer uterine involution and restoration of
  anatomy (by studies using MRI)
• -gt At least 6 months
• Shipp (2001)
• Interdelivery intervals of 18months or less
• -gt threefold increased risk of symptomatic
  uterine
• rupture

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Number of prior cesarean incision

• The risk of uterine rupture increases with the
  number of previous cesarean deliveries
• Landon (2004)
• twice as high in women with multiple prior
  cesareans compared with only one (1.4 versus
  0.7)
• Caughey (1999)
• five fold in two previous cesareans compared
  with only one (3.7 versus 0.8)
• Any previous vaginal delivery (before or after
  c/sec)
• -gt significantly improves the prognosis for a
  
• subsequent successful VBAC
• -gt lowers the risk of subsequent uterine
  rupture
• ACOG (2004)
• two prior low-transverse c/sec with a prior
  vaginal delivery
• should be considered for VBAC

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Indication for prior cesarean delivery

• The success rate for a trial of labor depends to
  the indication for the previous c/sec
• Wing and Paul (1999), OHerlihy(1998)
• breech presentation -gt 91 successful VBAC
• fetal distress -gt 84 successful VBAC
• dystocia -gt 68 successful VBAC
• Hoskins and Gomez (1997)
• (relation to cervical dilation)
• cervix 5cm or less -gt 67 successful VBAC
• cervix 6 to 9cm -gt 73 successful VBAC

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Fetal macrosomia

• Increasing fetal size would increase the risk of
  uterine rupture with VBAC
• Zelop (2001)
• weighed less than 4000g -gt 1.0 rupture
• Infants weighed at least 4000g -gt 1.6
  rupture
• birth weight exceeded 4250g -gt 2.4 ruptuer
• Elkousy (2003)
• no previous vaginal deliveries, the
  birthweight at
• least 4000g
• -gt the doubled risk of uterine rupture

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Maternal obesity

• Carroll (2003)
• As maternal weight increased, the rate of
• VBAC success decreased
• Edward (2003)
• Puerperal infection was higher in obese
• women attempting a trial of labor

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Labor and Delivery Considerations
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• Guidelines for women with a prior cesarean who
  have chosen a trial of labor (the ACOG,2002)
• ? Prompt evaluation of the laboring patient
  must be
• performed
• ? Continuous electronic monitoring of fetal
  heart rate and
• uterine contractions should be considered
• ? Personnel familiar with the potential
  complications of a trial of
• labor should be vigilant for nonreassuring
  fetal heart rate
• patterns and inadequate progress of labor
• ? Attempts should be limited to institutions
  with physicians
• immediately available to provide emergency
  care

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• The ACOG (2002) recommend that the following
  issues be addressed before the ultimate decision
  to attempt a vaginal delivery
• ? Advantages of a successful vaginal delivery,
  for
• example, shorter postpartum hospital stay
  less
• painful, more rapid recovery and others
• ? Contraindications to a trial of labor, for
  example,
• prior classical cesarean, placenta previa,
  and others
• ? Risk of uterine rupture (approximately 1)

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• ? Increased risk of uterine rupture with more
  than one
• prior cesarean delivery, attempts at
  cervical ripening
• or labor induction, macrosomia, and oxytocin
  
• augmentation
• ? In the event of rupture, there is a 10 to 25
  percent
• risk of significant adverse fetal sequelae
• ? Although catastrophic uterine rupture leading
  to
• perinatal death or permanent neonatal injury
  is rare,
• occurring less often than 1 per 1000 VBAC
  attempts,
• it dose occur despite the best available
  resources

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Cervical ripening and labor stimulation

• Any attempt to induce cervical ripening or
• to induce or augment labor
• gt Increases the risk of uterine rupture in
• women undergoing a trial of labor

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Cervical ripening and labor stimulation

• Oxytocin
• Use of oxytocin to induce or augment labor has
  been implicated in uterine ruptures in women
  attempting VBAC
• Oxytocin dose and duration correlated directly
  with uterine rupture
• The ACOG (2002)
• Oxytocin may be used for both labor induction
  
• and augmentation with close patient
  monitoring in
• women with a prior cesarean delivery
  undergoing
• a trial of labor

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Cervical ripening and labor stimulation

• Experiences at Parkland Hospital
• Between 1986 and 1990
• 1482 delivered vaginally,
• uterine rupture 1.5 per 1000
• Another 307 women received oxytocin,
• uterine rupture 10 per 1000
• gt Our experience with uterine ruptures led us
  to
• the decision to discontinue the use of
  oxytocin
• in women with prior cesarean deliveries

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Cervical ripening and labor stimulation

• Prostaglandins
• Prostaglandins use in women attempting VBAC
• -gt increases the risk of uterine rupture
• Ravasia (2000)
• the rate of uterine rupture was
  significantly
• greater in the women treated with
  prostaglandin
• E2 gel than in those having spontaneous
  labor
• (2.9 versus 0.5)
• Lydon-Rochelle (2001)
• The risk of uterine rupture was nearly 16-fold
  greater for women undergoing induction of labor
  with prostaglandins compared with that of a
  repeated cesarean delivery

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Epidural analgesia

• The use of epidural analgesia for labor in women
  with a prior cesarean delivery was debated in the
  past
• gt masking the pain of uterine rupture
• However
• Less than 10 of women with scar separation
  experience pain and bleeding
• Fetal heart rate decelerations are the most
  likely sign of rupture
• The ACOG (20020
• Epidural analgesia may safely be used during a
  trial of labor
• The anesthesia service be notified whenever a
  woman with a prior cesarean is admitted in active
  laobr

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Uterine scar exploration

• Surgical correction of a scar dehiscence is
  necessary only if significant bleeding is
  encountered
• Asymptomatic separations
• gt Do not generally require exploratory
• laparotomy and repair

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Uterine rupture
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Classification

• Complete uterine rupture
• All layer of the uterine wall separated
• Incomplete uterine rupture ( uterine dehiscence)
• Uterine muscle separated but visceral peritoneum
  is intact
• Morbidity and mortality are appreciably greater
  when rupture is complete
• The greatest risk factor for either complete or
  incomplete uterine rupture
• gt Prior cesarean delivery

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Diagnosis

• The symptoms and physical findings may appear
  bizarre unless the possibility of uterine rupture
  is dept in mind
• Hemoperitoneum
• Irritation of the diaphragm with pain
  referred to the chest
• -gt pulmonary or amnionic fluid embolism
• Intrauterine pressure catheters
• Few women experience cessation of contractions
  following
• uterine rupture
• gt not shown to assist reliably in the diagnosis
• The most common electronic fetal monitoring
  finding
• Sudden, severe heart rate decelerations
• (late decelerations, bradycardia, undetectable
  fetal heart action)

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Diagnosis

• Remarkably little appreciable pain or tenderness
• Most women in labor are treated for discomfort
  with narcotics, lumbar epidural analgesia
• The evident condition
• Signs of fetal distress
• Maternal hypovolemia from concealed hemorrhage
• Pelvic examination
• The fetal presenting part has entered the pelvis
  
• -gt Loss of station
• If the fetus is partly or totally extruded from
  the site of rupture
• -gt the presentign part moved away from the
  pelvic inlet
• -gt a firm contracted uterus may be felt
  alongside the fetus

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Prognosis

• Rupture and expulsion of the fetus into the
  peritoneal cavity
• -gt the chances for intact fetal survival are
  dismal
• -gt mortality rates 5075
• Fetal condition depends on how much placenta is
  intact
• -gt likely decreases over minutes
• If the fetus is alive at the time of rupture
• -gt immediate delivery, most often by
  laparotomy
• The maternal prognosis
• much better and seldom fatal
• If untreated -gt most women would die from
  hemorrhage or
• later from infection

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Hysterectomy versus repair

• Scar separation without bleeding
• Exploratory laparotomy is not indicated
• Frank rupture
• Hysterectomy may be required