Cervical Ripening

1
Cervical Ripening

• Dr Jessica Servey, FAAFP
• 15 March 2007
• Travis AFB Family Medicine Residency

2
Objectives

• Review the indications for cervical ripening
• Review the mechanical means of cervical ripening
• Look at pharmacologic for cervical ripening
• Consider risks and benefits of agents

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What is cervical ripening

• Process that is used to soften, dilate and efface
  the cervix
• Agents will often start labor

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Indications

• Postterm
• Hypertensive disorders
• Premature rupture of membranes
• Chorioamnionitis
• IUGR
• Isoimmunization
• Intrauterine fetal death
• Maternal medical complications
• Logistic factors

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Contraindications

• ABSOLUTE
• Placenta previa
• Vasa Previa
• Transverse/breech lie
• Prolapsed cord
• Prior classical c-section
• Active genital herpes

• RELATIVE
• Multifetal gestation
• Polyhydramnios
• Maternal cardiac conditions
• Grand multiparity
• Presenting part not in fetal pelvis

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Bishop score
Parameter 0 1 2 3
Dilation closed 1-2 3-4 gt5
Effacement 0-30 30-50 60-70 gt80
Station -3 -2 -1 to 0 1 to 2
Consistency firm Medium soft
Position posterior midposition anterior

• Described 1955
• Score at least 8 induction chances of vaginal
  delivery
• equivalent to spontaneous
• ACOG recommends score at least 6 for induction

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Methods to ripen

• Mechanical
• Laminaria
• Dilators
• Foley balloon
• Membrane stripping
• Acupuncture
• Pharmacologic
• Prostaglandin (Prepidil/Cervidil)
• Misoprostol
• Pitocin

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Mechanical Methods

• Laminaria
• Efficacious in cervical dilation
• Increased risk of intrauterine infection third
  trimester
• Hygroscopic cervical dilators
• Cheap
• Easy to place

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Mechanical Methods

• Membrane stripping
• Cochrane review of 19 trials, 17 compared with
  placebo
• NNT 7 to avoid one formal induction past 40 weeks
• No risk of infection
• Acupuncture
• LI4 and Sp6 can aid in cervical ripening
• Study demonstrated shortened interval to delivery

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Foley balloon

• First described in 1967
• Safe
• Cheap
• Easy to use in combination with pitocin
• May be useful for outpatient ripening

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Foley Balloon

• 2004 (30 vs 80 ml)
• 75 in 80ml group vs 58 in 30ml deliver within
  24 hours
• c-section rate not significant
• 2005 (extra amniotic saline infusion)
• No difference in vaginal delivery rates
• No difference in maternal or fetal complications

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Cervidil/Prepidil

• PGE2
• 3 methods of action
• Alters extracellular ground substance
• Affects smooth muscle of the cervix
• Gap junction formation
• Meta analysis of more than 7 studies show
  efficacy compared to placebo or oxytocin
• Storage/cost/user capability are issues

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Cervidil Placed in posterior vaginal fornix
Prepidil Intracervical placement
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Low dose pitocin

• 1 to 4 mu per minute for ripening
• 2002 study compared this to cytotec 50 ucg dose
• Interval to delivery - significantly less with
  cytotec
• Vaginal delivery 61 vs 65 (no difference)
• Cytotec higher c-s for fetal distress (27 vs 8)
• Pitocin higher c-s for labor dysfunction (26 vs
  10)
• Overall- same efficacy

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Misoprostol

• Dosing
• 25 mcg
• 50 mcg
• Intravaginal
• Oral
• Very cheap
• Easy to store
• NOT FDA APPROVED

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Misprostol 25 vs 50 ucg dose

• 50 ucg increase rate of vaginal delivery
• Shorter time to delivery
• Increased fetal distress related to uterine
  hyperstimulus
• Cochrane review with increased need for oxytocin
  with 25 but less uterine problems (NNT 25) and
  trend toward less neonatal ICU admissions
• Individual studies show differences in c-section
  rates

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Oral vs vaginal

• Study published 2005
• 212 women
• No statistical difference between time of first
  dose to time of delivery
• Pitocin used in 97 of both groups
• No difference in maternal complications, fetal
  complications, or side effects
• No difference in indication for c-section
• Dosing
• 25 ucg vaginally every 4 hours vs 50 ucg followed
  by 100 ucg orally every 4 hours

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Which is better?

• Study 2003 Cervidil vs cytotec (both had
  pitocin)
• Time to vaginal delivery not significant
• C-section rate not significant
• Reasons for c-section essentially the same
• Cochrane review
• Subgroup analysis with significantly larger of
  patient deliver within 24 hr with cytotec (nnt
  10)
• No change in c-section rate for PGE1 vs 2

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How to choose?

• Cost effectiveness
• Cervidil and prepidil vs cytotec and Foley
  balloon
• Cost of nursing staff
• ? Outpatient regimens
• How long must use pitocin
• Patient choice
• Only safety contraindicationPrior c-section
• Increased risk of uterine rupture using
  prostaglandins to ripen cervix for VBAC

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References

• Colon et al, Prospective Randomized Clinical
  Trial of inpatient cervical ripening with
  stepwise oral misoprostol vs vaginal misoprostol,
  American Journal of Obstetrics and Gynecology,
  2005, 192747-752.
• Cochrane database, Membrane sweeping for
  induction of labor, updated 2005.
• Levy et al, A randomized trial comparing a 30-ml
  and a 80-ml Foley catheter balloon for
  preinduction cervical ripening, American Journal
  of Obstetrics and Gynecology, 2004,
  1911632-1636.
• Bolnick et al, Randomized trial between two
  active labor management protocols in the presence
  of an unfavorable cervix, American Journal of
  Obstetrics and Gynecology, 2004124-128.
• Weaver, Sally,Vaginal Misoprostol for Cervical
  Ripening in Term Pregnancy, American Family
  Physician, February 2006, Vol 733, pg 511-512.
• ACOG Committee on Practice Bulletin-Obstetrics.
  Induction of Labor. ACOG Practice Bulletin No.
  10., November 1999. Obstetrics and Gynecology.
  199994(part1) 1-10.
• Lydon-Rochelle et al, Risk of uterine rupture
  during labor among women with prior cesarean
  delivery, New England Journal of Medicine, 2001,
  3453-8.
• Sanchez-Ramos, Luis, Induction of Labor,
  Obstetrics and Gynecology Clinics of North
  America, 2005, 32181-200.