induction lecture fmdrl

Getting Things Started… Getting Things Started… Cervical Ripening and Labor InductionCervical Ripening and Labor Induction

Jennifer Frank MDJennifer Frank MD

Fox Valley FMR ProgramFox Valley FMR Program

The best teachers…The best teachers…

Are our patients.Are our patients.– Case 1: 36 yo G2P1 at 39 weeks for social Case 1: 36 yo G2P1 at 39 weeks for social

induction.induction.VBACVBAC

Cytotec for cervical ripeningCytotec for cervical ripening

– Case 2: 29 yo G1 at 40 +2 weeks for social Case 2: 29 yo G1 at 40 +2 weeks for social inductioninduction

Cytotec for cervical ripeningCytotec for cervical ripening

Take home points (or learning Take home points (or learning objectives)objectives)

Cervical ripening, labor induction, and labor Cervical ripening, labor induction, and labor augmentation carry risks that are potentially augmentation carry risks that are potentially serious to mom and baby and must be weighed serious to mom and baby and must be weighed by the potential benefit.by the potential benefit.

There is good evidence to direct the safe use of There is good evidence to direct the safe use of cervical ripening agents and agents used for cervical ripening agents and agents used for labor induction and labor augmentation.labor induction and labor augmentation.

There are clinical indications when labor There are clinical indications when labor induction (+/- cervical ripening) is appropriate.induction (+/- cervical ripening) is appropriate.

Indications for Labor InductionIndications for Labor Induction

Maternal and fetal indicationsMaternal and fetal indications– Placental abruptionPlacental abruption– ChorioamnionitisChorioamnionitis– Fetal demiseFetal demise– Gestational hypertension, preeclampsia, eclampsiaGestational hypertension, preeclampsia, eclampsia– Premature ROMPremature ROM– Postterm pregnancyPostterm pregnancy– Maternal medical indicationsMaternal medical indications– Fetal compromise (e.g. IUGR)Fetal compromise (e.g. IUGR)

Indications for InductionIndications for Induction

Other types of indicationsOther types of indications– Risk of rapid laborRisk of rapid labor– Distance from hospitalDistance from hospital– Psychosocial indicationsPsychosocial indications

ACOG Practice Guideline No. 10. Induction of labor.ACOG Practice Guideline No. 10. Induction of labor.

Contraindications to Labor InductionContraindications to Labor Induction

Vasa previaVasa previa

Complete placenta previaComplete placenta previa

Transverse fetal lieTransverse fetal lie

Umbilical cord prolapseUmbilical cord prolapse

Previous transfundal uterine surgeryPrevious transfundal uterine surgery


Additional ContraindicationsAdditional Contraindications

AbsoluteAbsolute– Pelvic structural Pelvic structural

abnormalityabnormality– Active genital herpes Active genital herpes

infectioninfection– Invasive cervical Invasive cervical

cancercancer

RelativeRelative– Abnormal FHTAbnormal FHT– Breech presentationBreech presentation– Maternal heart diseaseMaternal heart disease– Multifetal pregnancyMultifetal pregnancy– PolyhydramniosPolyhydramnios– Presenting part above Presenting part above

pelvic inletpelvic inlet– Severe maternal Severe maternal

hypertensionhypertension

Harman JH, Kim A. Current trends in cervical ripening and labor induction. AFP 1999;60:477-84.

Successful Labor InductionSuccessful Labor Induction

Different definitions of successDifferent definitions of success– Achieve vaginal delivery in specified time (12-Achieve vaginal delivery in specified time (12-

24 hours)24 hours)– Achieve active labor within a specified timeAchieve active labor within a specified time– Achieve active laborAchieve active labor

Factors Predicting SuccessFactors Predicting Success

Cervical statusCervical status– Traditional Bishop score Traditional Bishop score >> 9 9– Favorable score varies from Favorable score varies from >> 5 to 5 to >> 8 8– Inverse relationship b/w cervical score and Inverse relationship b/w cervical score and

length of latent phase of laborlength of latent phase of labor– Increased risk of cesarean delivery with Increased risk of cesarean delivery with

“unfavorable” cervix (generally < 5)“unfavorable” cervix (generally < 5)

Crane JM. Factors predicting labor induction success: A critical analysis 2006; Crane JM. Factors predicting labor induction success: A critical analysis 2006;

Clin Obstet Gynecol 49;573-84.Clin Obstet Gynecol 49;573-84.

Maternal Factors Maternal Factors

Maternal characteristicsMaternal characteristics– ParityParity

Variable evidence for the weight this has on predicting Variable evidence for the weight this has on predicting delivery within 24 hoursdelivery within 24 hours

– HeightHeightAssociation between taller women and increased chance of Association between taller women and increased chance of vaginal delivery within 12-24 hours of starting labor inductionvaginal delivery within 12-24 hours of starting labor induction

– WeightWeightLower weight – more likely to be successfulLower weight – more likely to be successful

– AgeAgeYounger women are more likely to be successfulYounger women are more likely to be successful

Fetal FactorsFetal Factors

Higher birth weights (>3.5 kg) associated Higher birth weights (>3.5 kg) associated with increased risk for failed induction with increased risk for failed induction (lower rate of vaginal delivery within 24 (lower rate of vaginal delivery within 24 hours)hours)

Increasing gestational age associate with Increasing gestational age associate with increased likelihood of labor increased likelihood of labor induction induction successsuccess

Fetal maturityFetal maturity

Criteria for establishing fetal maturityCriteria for establishing fetal maturity– Fetal heart tones documented for at least 20 weeks Fetal heart tones documented for at least 20 weeks

by nonelectronic fetoscope or for 30 weeks by by nonelectronic fetoscope or for 30 weeks by DopplerDoppler

– At least 36 weeks since a positive HCG (serum or At least 36 weeks since a positive HCG (serum or urine)urine)

– At least 39 weeks' gestation based on crown-rump At least 39 weeks' gestation based on crown-rump length performed at 6–11 weeks' gestationlength performed at 6–11 weeks' gestation

– At least 39 weeks' gestation based on ultrasound At least 39 weeks' gestation based on ultrasound measurement at 12–20 weeks' gestationmeasurement at 12–20 weeks' gestation

Sanchez-Ramos L. Induction of labor. Obstet Gynecol Clin North Am - 01-JUN-2005; 32(2): 181-200, viiiSanchez-Ramos L. Induction of labor. Obstet Gynecol Clin North Am - 01-JUN-2005; 32(2): 181-200, viii

Cervical RipeningCervical Ripening

Softening, effacement, dilation preceding Softening, effacement, dilation preceding active laboractive labor

Prostaglandins play an unknown role in Prostaglandins play an unknown role in mediating cervical ripeningmediating cervical ripening

When is it needed?When is it needed?– ““Unripe cervix” based on cervical score Unripe cervix” based on cervical score

(usually < 6 on Bishop score)(usually < 6 on Bishop score)

Bishop scoreBishop score

FactorFactor 00 11 22 33

DilationDilation 00 1-21-2 3-43-4 5-65-6

Effacement (%)Effacement (%) 0-300-30 40-5040-50 60-7060-70 8080

StationStation -3-3 -2-2 -1 or 0-1 or 0 +1 to +2+1 to +2

ConsistencyConsistency FirmFirm MedMed SoftSoft ______

PositionPosition PostPost MidMid AnterAnter ______

Assessing CervixAssessing Cervix

TVUSTVUS– More objectiveMore objective– Not superior to Bishop score in meta-analysisNot superior to Bishop score in meta-analysis

Fetal fibronectinFetal fibronectin– May bind placenta and membranes to deciduaMay bind placenta and membranes to decidua– Presence associated with preterm birthPresence associated with preterm birth– Not superior to Bishop scoreNot superior to Bishop score

Insulin-like growth factor binding protein-1Insulin-like growth factor binding protein-1– Synthesized by maternal decidua, may be released Synthesized by maternal decidua, may be released

with cervical ripening and fetal membrane separating with cervical ripening and fetal membrane separating from deciduafrom decidua

– May indicate cervical “ripeness”May indicate cervical “ripeness”

Methods of cervical ripeningMethods of cervical ripening

Low dose oxytocinLow dose oxytocin– << 4 mU/minute 4 mU/minute

Dinoprostone (PGEDinoprostone (PGE22))– Intravaginal or intracervicalIntravaginal or intracervical– FDA approved for cervical ripeningFDA approved for cervical ripening– Pt needs to be recumbent for 30 minutes and Pt needs to be recumbent for 30 minutes and

should be monitored for 1-4 hoursshould be monitored for 1-4 hours– Onset of contractions usu. within 1Onset of contractions usu. within 1stst hour, hour,

peak at 4 hourspeak at 4 hours

Methods of cervical ripening Methods of cervical ripening continuedcontinued

Misoprostol: PGEMisoprostol: PGE11

– Not FDA approved for this indicationNot FDA approved for this indication– Oral or vaginal administration*Oral or vaginal administration*– 3x systemic bioavailability of vaginal vs. oral3x systemic bioavailability of vaginal vs. oral– As or more effective than other methodsAs or more effective than other methods– Increased risk of tachysystoleIncreased risk of tachysystole

Has not equated with worse overall outcomesHas not equated with worse overall outcomes

– Hyperstimulation occurs in 1-10% of patientsHyperstimulation occurs in 1-10% of patients– Cheaper and more convenientCheaper and more convenient– Recommend informed consentRecommend informed consent

Nonpharmacologic methods for Nonpharmacologic methods for cervical ripeningcervical ripening

Stripping or sweeping the membranesStripping or sweeping the membranes– Causes an increase in prostaglandinsCauses an increase in prostaglandins– Insert finger through internal cervical os and move in Insert finger through internal cervical os and move in

a circular direction to detach the inferior part of the a circular direction to detach the inferior part of the membranes from the lower uterine segmentmembranes from the lower uterine segment

– Risks: infection, bleeding, accidental amniotomy, Risks: infection, bleeding, accidental amniotomy, discomfortdiscomfort

– Alone is not effective but may reduce dose of oxytocin Alone is not effective but may reduce dose of oxytocin neededneeded

– Important note: Strippingmembranes.com is for saleImportant note: Strippingmembranes.com is for sale

Nonpharmacologic methods for Nonpharmacologic methods for cervical ripening continuedcervical ripening continued

Mechanical dilators – local pressure stimulating Mechanical dilators – local pressure stimulating release of prostaglandins and dilating cervixrelease of prostaglandins and dilating cervix– Hygroscopic (osmotic) dilatorsHygroscopic (osmotic) dilators– Balloon devices (Foley bulb)Balloon devices (Foley bulb)

Method & materialsMethod & materials

– Effective for cervical ripening (compared to Effective for cervical ripening (compared to misoprostol, PGEmisoprostol, PGE22))

AmniotomyAmniotomy– Increases production/release of prostaglandinsIncreases production/release of prostaglandins– Evidence does not support use for labor inductionEvidence does not support use for labor induction

Alternative methods for cervical Alternative methods for cervical ripeningripening

Evening primrose oil, Black Haw, Black and blue cohosh, Evening primrose oil, Black Haw, Black and blue cohosh, red raspberry leavesred raspberry leaves– All have uncertain roleAll have uncertain role

Castor oil, hot baths, enemas Castor oil, hot baths, enemas – No evidence to support useNo evidence to support use

Sexual intercourse – stimulation of oxytocin release and Sexual intercourse – stimulation of oxytocin release and prostaglandinsprostaglandins– Uncertain role, but fun to try.Uncertain role, but fun to try.

Breast stimulationBreast stimulation– May be helpful but no good evidenceMay be helpful but no good evidence

Acupuncture/transcutaneous nerve stimulationAcupuncture/transcutaneous nerve stimulation– May have benefit, need better studiesMay have benefit, need better studies

Tenore, JL. Methods for cervical ripening and induction of labor. AFP 2003.Tenore, JL. Methods for cervical ripening and induction of labor. AFP 2003.

Labor InductionLabor Induction

Stimulating uterine contractions to Stimulating uterine contractions to promote delivery prior to the onset of promote delivery prior to the onset of spontaneous active laborspontaneous active labor

Rate is > 20% and increasingRate is > 20% and increasing

Most common indication is postterm Most common indication is postterm pregnancypregnancy

Risks of Labor InductionRisks of Labor Induction

Operative vaginal deliveryOperative vaginal delivery

Cesarean deliveryCesarean delivery

Excessive uterine activity with abnormal Excessive uterine activity with abnormal FHR patterns (uterine hyperstimulation)FHR patterns (uterine hyperstimulation)

Delivery of preterm infantDelivery of preterm infant

Labor Induction - ACOGLabor Induction - ACOG

PGE analogues are effective for both cervical PGE analogues are effective for both cervical ripening and labor induction (Level A)ripening and labor induction (Level A)Cytotec at doses of 25 micrograms every 3-6 Cytotec at doses of 25 micrograms every 3-6 hours are effective for cervical ripening and hours are effective for cervical ripening and labor induction (Level A)labor induction (Level A)With term PROM, may induce labor with With term PROM, may induce labor with prostaglandins (Level A)prostaglandins (Level A)Increased complications with doses of cytotec > Increased complications with doses of cytotec > 50 mcg (Level B)50 mcg (Level B)Avoid cytotec in VBAC (Level B)Avoid cytotec in VBAC (Level B)

Methods of Labor InductionMethods of Labor Induction

OxytocinOxytocin– Oxytocin receptors in the uterus increase starting at Oxytocin receptors in the uterus increase starting at

32 weeks 32 weeks – IV administration of solution of 10 Units to 1 Liter of IV administration of solution of 10 Units to 1 Liter of

isotonic solution = 10 mU/1mLisotonic solution = 10 mU/1mL– Continuous infusion vs. pulsed dosingContinuous infusion vs. pulsed dosing

Continuous usually start at 0.5 to 2.5 mU/min increased by Continuous usually start at 0.5 to 2.5 mU/min increased by same increment every 15-60 minutessame increment every 15-60 minutes

Effect within 3-5 minutes, steady state by 15-30 min.Effect within 3-5 minutes, steady state by 15-30 min.

No clearly superior regimen – great variability in responseNo clearly superior regimen – great variability in response

Methods of Labor InductionMethods of Labor Induction

PGEPGE11

PGEPGE22

OxytocinOxytocin

Oxytocin continuedOxytocin continued

Oxytocin is good…Oxytocin is good…– It is potentIt is potent– May titrateMay titrate– Short half-lifeShort half-life– Well toleratedWell tolerated

Oxytocin for labor inductionOxytocin for labor induction

Low-doseLow-dose– Start at 0.5-2 mU/minStart at 0.5-2 mU/min– Increase by 1-2 mU/min every 15-40 minutesIncrease by 1-2 mU/min every 15-40 minutes

High-doseHigh-dose– Start at 6-8 mU/minStart at 6-8 mU/min– Increase by 6 mU/min every 15-40 minutesIncrease by 6 mU/min every 15-40 minutes

High-dose results in shorter labor, decreased High-dose results in shorter labor, decreased intra-amniotic infections, and decreased rates of intra-amniotic infections, and decreased rates of c/section for dystocia but higher risk of c/section for dystocia but higher risk of hyperstimulationhyperstimulation

Sanchez-Ramos L. Induction of labor. Obstet Gynecol Clin North Am - 01-JUN-2005; 32(2): 181-200, viiiSanchez-Ramos L. Induction of labor. Obstet Gynecol Clin North Am - 01-JUN-2005; 32(2): 181-200, viii

Dosing of OxytocinDosing of Oxytocin

Commonly accepted practice is to increase by 1-Commonly accepted practice is to increase by 1-2 mU/min every 40 minutes2 mU/min every 40 minutes– May optimize pharmacokinetics by not increasing May optimize pharmacokinetics by not increasing

dose before steady-state is reacheddose before steady-state is reached– Lower risk of hyperstimulationLower risk of hyperstimulation– May result in longer labor for oxytocin-insensitive May result in longer labor for oxytocin-insensitive

womenwomen– May result in lower overall dose of oxytocin requiredMay result in lower overall dose of oxytocin required

Usual doseUsual dose– More than 90% of women will respond to 16 mU/min More than 90% of women will respond to 16 mU/min

or lessor less– Rare for women to require 20-40 mU/minRare for women to require 20-40 mU/min

Potential RisksPotential RisksStripping membranesStripping membranes– Bleeding from undiagnosed placenta previa or low-lying placentaBleeding from undiagnosed placenta previa or low-lying placenta– Accidental amniotomyAccidental amniotomy

Nipple stimulationNipple stimulation– Uterine hyperactivityUterine hyperactivity– FHR decelsFHR decels

AmniotomyAmniotomy– Unpredictable length of time until onset of contractionsUnpredictable length of time until onset of contractions– Cord prolapseCord prolapse– ChorioamnionitisChorioamnionitis– Cord compressionCord compression– Vasa previa ruptureVasa previa rupture

LaminariaLaminaria– Increased maternal/fetal infectionsIncreased maternal/fetal infections


Potential Risks cont’dPotential Risks cont’dMisoprostol (cytotec)Misoprostol (cytotec)– Tachysystole, hyperstimulationTachysystole, hyperstimulation– Uterine ruptureUterine rupture– Increase in meconium staining of AFIncrease in meconium staining of AF– Abnl FHR tracingAbnl FHR tracing– Likely dose and route dependentLikely dose and route dependent

Intravaginal/intracervical PGEIntravaginal/intracervical PGE22

– 1-5% rate of uterine hyperstimulation1-5% rate of uterine hyperstimulation– Fever, vomiting, diarrheaFever, vomiting, diarrhea– Uterine rupture secondary to hyperstimulationUterine rupture secondary to hyperstimulation

OxytocinOxytocin– Dose relatedDose related– HyperstimulationHyperstimulation– FHR decelsFHR decels– Placental abruption/uterine rupture secondary to hyperstimPlacental abruption/uterine rupture secondary to hyperstim– Water intoxicationWater intoxication– Antidiuretic effect and hypotension with large/rapid IV administrationAntidiuretic effect and hypotension with large/rapid IV administration


Questions & CommentsQuestions & Comments

ReferencesReferences

ACOG Practice Bulletin No 10 Induction of Labor, 1999.ACOG Practice Bulletin No 10 Induction of Labor, 1999.Crane JM. Factors predicting labor induction success: Crane JM. Factors predicting labor induction success: A critical analysis 2006; Clin Obstet Gynecol 49;573-84.A critical analysis 2006; Clin Obstet Gynecol 49;573-84.Harman JH, Kim A. Current trends in cervical ripening Harman JH, Kim A. Current trends in cervical ripening and labor induction. AFP 1999;60:477-84.and labor induction. AFP 1999;60:477-84.Tenore JL. Methods for cervical ripening and induction Tenore JL. Methods for cervical ripening and induction of labor. AFP 2003;67:2123-8.of labor. AFP 2003;67:2123-8.Weeks A. Oral misoprostol administration for labor Weeks A. Oral misoprostol administration for labor induction. Clin Obstet Gynecol 2006;49:658-71.induction. Clin Obstet Gynecol 2006;49:658-71.

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