INDUCTION OF INDUCTION OF LABOURLABOURDr Max MongelliDr Max Mongelli

Women & Childrens’ HealthWomen & Childrens’ HealthNepean HospitalNepean Hospital

DefinitionsDefinitions

IOL: “Iatrogenic stimulation of uterine IOL: “Iatrogenic stimulation of uterine contractions to accomplish delivery prior to the contractions to accomplish delivery prior to the spontaneous onset of labour”spontaneous onset of labour”Cervical priming: Interventions designed to Cervical priming: Interventions designed to improve the Bishop score without necessarily improve the Bishop score without necessarily inducing labourinducing labour

PrevalencePrevalence

USA: frequency has increased from 9.5% USA: frequency has increased from 9.5% to 22.5% over 16 yearsto 22.5% over 16 years Due to availability of better cervical Due to availability of better cervical ripening agents, more relaxed attitudes ripening agents, more relaxed attitudes towards marginal indications for towards marginal indications for inductioninduction

IndicationsIndications

MaternalMaternal FetalFetal

Maternal IndicationsMaternal Indications

Maternal IndicationsMaternal Indications

Pre-eclampsia/EclampsiaPre-eclampsia/Eclampsia Severe hypertensionSevere hypertension Gestational diabetesGestational diabetesPelvic arthropathyPelvic arthropathy Obstetric cholestasisObstetric cholestasis Severe cardio-respiratory diseaseSevere cardio-respiratory disease “ “Social”Social” AnticoagulationAnticoagulation

Fetal IndicationsFetal Indications

Fetal IndicationsFetal Indications

Post-term pregnancyPost-term pregnancy IUGRIUGR Obstetric cholestasisObstetric cholestasis PROMPROMAmnionitisAmnionitis Fetal demiseFetal demise

ContraindicationsContraindications

ContraindicationsContraindications

Classical C/S scarClassical C/S scar Transmural myomectomy scarTransmural myomectomy scar Placenta or vasa previaPlacenta or vasa previa Active genital herpesActive genital herpes Large cervical fibroidsLarge cervical fibroids MalpresentationMalpresentation Cord presentation or prolapseCord presentation or prolapse Severe IUGRSevere IUGR Abnormal or non-reactive CTGAbnormal or non-reactive CTG

Pre-Induction AssessmentPre-Induction Assessment

Confirm valid indicationConfirm valid indication Exclude contraindicationsExclude contraindications Patient information and consentPatient information and consent Bishop scoreBishop score

Pre-Induction Assessment:Pre-Induction Assessment:Bishop ScoreBishop Score

Modified Bishop scoreModified Bishop score

Significance of Bishop scoreSignificance of Bishop score

If Bishop score >5 chance of vaginal If Bishop score >5 chance of vaginal delivery after IOL same as after delivery after IOL same as after spontaneous onset of labourspontaneous onset of labour

Predictors of Successful IOLPredictors of Successful IOL

Other Predictors of Successful IOLOther Predictors of Successful IOL

MultiparityMultiparity Tall stature ( > 5 ft 5” or 165 cm)Tall stature ( > 5 ft 5” or 165 cm) Normal BMINormal BMI Increasing GAIncreasing GA EFW < 3500 gEFW < 3500 g

Methods for Induction of LabourMethods for Induction of Labour

MethodsMethods

Membrane strippingMembrane stripping Mechanical methodsMechanical methods AmniotomyAmniotomy OxytocinOxytocin ProstaglandinsProstaglandins

Membrane StrippingMembrane Stripping

Finger through cervical os, to detach membranes Finger through cervical os, to detach membranes from LUSfrom LUS Usually from 39 weeks onwardsUsually from 39 weeks onwards Can be repeated safelyCan be repeated safely Reduced risk of going beyond 41 (RR 0.59)Reduced risk of going beyond 41 (RR 0.59) Reduced frequency of formal IOL (NNT =8)Reduced frequency of formal IOL (NNT =8) May cause slight PV bleeding and crampsMay cause slight PV bleeding and cramps

Mechanical MethodsMechanical Methods

Required for low Bishop scoresRequired for low Bishop scores Ideal when PG’s relatively contraindicatedIdeal when PG’s relatively contraindicated Foley’s catheterFoley’s catheter ATAD catheterATAD catheter LaminariaLaminaria

AmniotomyAmniotomy

Usually when cx is partially dilatedUsually when cx is partially dilated Usually combined with oxytocinUsually combined with oxytocin Colour of amniotic fluid should be Colour of amniotic fluid should be notednoted

Risks of AmniotomyRisks of Amniotomy

Fetal hemorrhage if vasa previaFetal hemorrhage if vasa previa Cord prolapse, esp with high headCord prolapse, esp with high head InfectionInfection

OxytocinOxytocin

Almost always after amniotomyAlmost always after amniotomy Given i.v. by infusion pump because of short half-lifeGiven i.v. by infusion pump because of short half-life May take up to 40 mins to reach steady-state May take up to 40 mins to reach steady-state concentrationsconcentrations May be stopped once active phase of labour establishedMay be stopped once active phase of labour established Continuous CTG monitoring requiredContinuous CTG monitoring required

Oxytocin regimesOxytocin regimes

Low-dose: less likely to cause hyperstimulationLow-dose: less likely to cause hyperstimulation High dose: short incremental time intervals, no High dose: short incremental time intervals, no more than 40 iu/minmore than 40 iu/min Pulsatile regime: boluses at 8-10 min intervals, Pulsatile regime: boluses at 8-10 min intervals, reduced total overall dose of of oxytocinreduced total overall dose of of oxytocin

Risks of OxytocinRisks of Oxytocin

Hyperstimulation / tachysystoleHyperstimulation / tachysystole Uterine ruptureUterine rupture High dose: water intoxicationHigh dose: water intoxication Increased risk of PPHIncreased risk of PPH

ProstaglandinsProstaglandins

Required for low Bishop scoresRequired for low Bishop scores PGE2 gel or pessariesPGE2 gel or pessaries Slow-release systemsSlow-release systems MisoprostolMisoprostol

Prostanoids in Clinical UseProstanoids in Clinical Use

Dinoprostone (PGE2)Dinoprostone (PGE2) Dinoprost (PGF2-alpha)Dinoprost (PGF2-alpha) Gemeprost: “cervagem”, analogue of PG E1, Gemeprost: “cervagem”, analogue of PG E1, for TOPsfor TOPs Carboprost (analogue of PGF2-alpha)Carboprost (analogue of PGF2-alpha) Misoprostol (stable PGE2 analogue)Misoprostol (stable PGE2 analogue)

Side Effects of ProstaglandinsSide Effects of Prostaglandins

SE’s of ProstaglandinsSE’s of Prostaglandins

HyperstimulationHyperstimulation FeverFever Allergic reactionsAllergic reactions Exacerbation of asthmaExacerbation of asthma

Other Methods of IOLOther Methods of IOL

Other Methods of IOLOther Methods of IOL

Nipple stimulationNipple stimulation Castor oilCastor oil Cervical vibratorsCervical vibrators AcupunctureAcupuncture SexSex

Prostaglandins in SemenProstaglandins in Semen

PGE : 67.1 mg/LPGE : 67.1 mg/L PGF: 3.2 mg/LPGF: 3.2 mg/L

Patient’s consent for IOLPatient’s consent for IOL

Indication to be explainedIndication to be explained Failure rate and need for C/SFailure rate and need for C/S Possible delay in starting IOLPossible delay in starting IOL Risks to be explained: cord prolapse, fetal Risks to be explained: cord prolapse, fetal distress, PPHdistress, PPH Alternatives to inductionAlternatives to induction Patient info. sheetPatient info. sheet