Induction of labour Flashcards by Merrin Rutherford

Discuss elective IOL at term: Cochrane review findings (2020)
-Number of studies included (1)
-What it looked at (2)
-Results (7)

Includes 34 RCT with IOL for low risk women at or beyond term - 19, 000 women
Excluded trials where there was an indication for IOL
Results
-Lower all cause perinatal death RR 0.31
-Need 544 IOL to prevent 1 perinatal death
-Lower still birth rate RR 0.30
-Lower CS rate RR 0.90
-No increase in PPH or perineal trauma, operative vaginal delivery
-Reduced risk of NICU admission and apgars <7 at 5 mins

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Discuss membrane sweeping
-Evidence for use (1)
-When to offer (1)
-Advantages
-Disadvantages

Evidence for use
-Reduces the need for IOL
-NNT 8 to avoid formal IOL
-Increased chance of spontaneous labour
-No difference between SVB or CS
-Data is of low certainty
When to offer
-Offer to all women from 39 weeks to avoid going post dates
-Offer at start of formal IOL - reduces exposure to synto
Advantages
-Shortens IOL to delivery interval
-Reduces Oxy use
-No increased risk of infection
Disadvantages
-Increased maternal pain and bleeding
-Unclear how often to offer

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Discuss induction of labour
-Definition
-Incidence
-Outcomes

Definition
-Artificial initiation of uterine contraction before the onset of spontaneous contractions
Prevalence
-1:4 pregnancies in NZ (rising rate)
-1:5 pregnancies in Australia
Outcomes
-Approximately 15% have instrumental deliveries
-Approximately 22% have CS

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What are the indications for IOL (MoH guidelines).
-What conditions should it be offered (8)
-When should it be offered
-What risks are avoided

Prolonged gestation
-IOL 41-42 weeks
-Lowers risk of: perinatal death, CS, NICU admission, operative VB, lower mec
Term ROM
-IOL within 24hrs
-IOL immediately if GBS + or Mec
-Reduces risk of infection mother and baby, NICU admission, PN abx use, No impact to operative delivery
SGA/IUGR
-IOL at 38 weeks if IUGR but no dopplers available
-IOL at 37 weeks if abnormal UAPI
-IOL at 38 weeks if abnormal MCAPI/CPR or EFW <3rd
-IOL at 40 weeks if normal LV + dopplers and EFW >3rd
Diabetes in pregnancy
-IOL at 40-41 weeks if uncomplicated GDM
-IOL at 38 weeks if fetal macrosomia or other co-morbidities
-IOL at 39 weeks if pre-existing diabetes if no comorbidity
-IOL T1DM on case by case basis
Obstetric cholestasis
-Consider IOL >37 weeks considering bile salts
AMA
-Offer IOL from 39-40 weeks
-Risk of still birth for women >40 double (2:1000)
-Risk of still birth for woman >40 at 39/40 same as woman in 20’s at 41 weeks
-Limited evidence to support IOL
Hypertension
-IOL anytime after 37 weeks for PET
-IOL for chronic HTN but otherwise low risk consider expectant management >37 weeks
-IOL for women with gHTN onset post 37/40 consider IOL to avoid worsening of condition
Multiple pregnancy
-DCDA twins IOL 37-38 weeks
-MCDA twins IOL 36-37 weeks

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Discuss indications for IOL:
1. What conditions should IOL not be offered in (5)
2. What conditions is IOL controversial (4)

Conditions where IOL is not indicated
-ART
-Previous CS
-Previous precipitous labour
-Obesity - higher risk SB but higher IOL failure
-Isolated oligohydramnios
Conditions where IOL is controversial
-Recurrent APH at term
-Reduced FM
-Suspected macrosomia in the absence of diabetes
-Previous still birth

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When is IOL contraindicated
-Absolute contra-indications (6)
-Relative contraindications (3)

Absolute contraindications
-Placenta praevia/ vasa praevia
-Transverse lie
-Active first episode of genital herpes
-Cord prolapse
-Previous classical section
-Maternal or fetal anaomaly that prohibits VB
Relative contraindication
-Triplets or higher order pregnancy
-Breech presentation
-Two or more previous low transverse CS

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Discuss risks of IOL (7)

Uterine hyperstimulation
Fetal distress - usually due to decreased uterine blood flow
Failed IOL
CS if IOL in IUGR preterm (OR 2.7) or PET/HTN preterm
Cord prolapse
Uterine rupture
Increased pain cf spont labour

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Discuss failed IOL
-Definitions (2)
-Predictors of failed IOL (4)
-Management options (4)

Definitions
-Cervix does not change to allow ARM
-12-15hrs of oxytocin without establishing into active labour
Predictors of failed IOL
-Low bishop score
-Maternal weight
-Maternal age
-LLP
-If 10hrs of synto and not in active labour 75%
chance of CS
-If 12 hours of synto and not in active labour chance
of CS 90%
Management options
-Reattempt following day
-Use alternative IOL method
-Await spontaneous labour
-CS

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Discuss risk of CS associated with IOL
-When risk of CS is increased (2)
-When risk of CS is decreased (3)
-When risk of CS remains unchanged (5)

Risk of CS is increased
-Preterm IUGR
-Preterm HTN/PET
2.Risk of CS is decreased
-Post dates
-HTN or mild PET at term
-Maternal request
No change in CS rate
-Diabetes
-Twins
-PPROM/PROM
-IUGR at term
-Macrosomia

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Discuss impact of medications used for IOL
-Adverse effects of oxytocin (9)
-Adverse effects of prostaglandins (8)

Adverse effects of oxytocin
-Fluid retention
-Hyponatremia
-N&V
-Arrythmias
-Anaphylaxis
-Placental abruption
-AFE
-Hyperstimulation
-Uterine rupture
Prostaglandins
-N&V&D
-AFE
-Abruption
-Fetal distress
-Maternal HTN
-Bronchospasm
-Fever
Vaginal discomfort

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Discuss risks associated with IOL in women with previous CS (5)

Increased risk of uterine rupture / dehiscence by 2-3 times
Increase need for repeat CS compared VBACs who spontaneously labour 1.5 times
Increased risk of uterine rupture with prostaglandins - 3 times (7.7/1000 to 24.5 / 1000)
increased risk of uterine rupture with oxytocin 4 times (1:200 to 2:100)
Risk of induction with balloon - lower chance of uterine rupture

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Discuss bishops score
-What does the bishop score comprise of
-Significance of a score >=9
-Significance of a score >=8
-Significance of a score <6

Composition of Bishops score
-Score with 0,1 or 2
-Cervical dilatation <1, 1-2, 3-4
-Length of cervix >2, 1-2, <1
-Station of PP -3, -2, -1
-Consistency - firm medium soft
-Position - posterior, central, anterior
Significance of BS>=9
-Chance of VB same as spont labour
Significance of BS >=8
-Chance of failed IOL 3%
Significance of score <6
-Cervical ripening required

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Discuss prostaglandins for cervical ripening
-Mode of action (1)
-Justification for use in IOL (1)
-Types (5)
-Time between different prostaglandin commencement of oxy (3)

Mode of action
-Softens cervix and brings on uterine contractions
Justification of use
-Use in women with unfavourable cervix improves chance of VB within 24hrs compared to oxy alone
Types
Prostaglandin E2 - dinoprostone
-Prostin Gel 1 or 2 mg every 6hrs
-Cervadil pessary 10mg for 24hrs
-Tablet 3mg PV every 6-8hrs
Prostaglandin E1 - Misoprostol
-PV or PO 25mcg Q2H
Time between prostaglandin and oxy
-Prostin gel - 6hrs
-Cervadil - 30mins
-Misoprostol - 4hrs

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Compare outcomes between using cervadil and prostin gel (5)

Similar rates of VB within 24hrs
-No difference in CS rates
-No difference in hyperstimulation with FHR changes - overall rate 5%
-Cervidil associated with less instrumental deliveries
-Cervidil associated with less rates of cervix remaining unfavourable

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Discuss outcomes of PV misoprostol compared to PGE2 PV (6)

-Higher chance of VB within 24hrs with miso
-Less need for oxytocin augmentation with miso
-Less use of epidural with miso
-No difference in uterine hyperstimulation between the two
-No difference in CS rates
-Higher mec stained liquor with miso

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Discuss outcomes for PO miso vs PV misoprostol (6)

-Similar rates of VB within 24hrs
-Similar CS rates
-Less hyperstimulation with PO miso
-Less PPH with PO miso
-Less low 5 mins apgar scores with PO miso
-Higher mec with PO miso

Discuss outcomes for PO miso vs PV PGE2 (1)

Lower CS rates in PO miso RR 0.88
-Overall CS rate for PO miso 15%

Discuss contraindications for use of misoprostol (6)

-PTL
-Multiple pregnancy
-Previous CS or uterine surgery
-IUGR with abnormal dopplers or EFW <5%
-Suspicion of fetal compromise including abnormal CTG
-Maternal conditions - severe asthma, cardiovascular conditions

Discuss mechanical ripening of the cervix for IOL
-Mechanism (2)
-Contraindications (1)
-Method (3)
-Advantages (2)
-Disadvantages (5)

Mechanism
-Direct physical pressure on internal os
-Increase release of prostaglandins from decidua, adjacent membranes, cervix
Contra-indications
-Low lying placenta
Method
-Single or double balloon passed transcervically for 12-24hrs
-Inflation of balloon >30mL associated with higher rate of birth within 24hrs compared to low inflation
-Little difference in outcomes with single or double balloon
Advantages
-Lower cost
-Reduced side effects
Disadvantages
-Difficulty with insertion
-Discomfort for woman
-Risk of infection
-Fetal malposition once balloon removed
-Urinary retention

Compare outcomes between balloon catheter IOL and PGE2 (dinoprost) - Most useful (7 points)

-No difference in CS
-No difference in assisted VB
-No difference in birth not achieved within 24hrs
-Balloon associated with more need for oxytocin
-Balloon associated with less uterine hyperstimulation
-Balloon associated with less neonatal morbidity RR 0.48
-Balloon associated with reduced risk of NICU

Compare outcomes between balloon catheter and PO misoprostol

-Balloon associated with increased risk of NO VB within 24hrs
-Balloon associated with increased CS rate (Also true if comparing with PV miso)

Discuss ARM for IOL
-Indications (3)
-Timing of AMR in IOL process
-Comparison of ARM alone vs ARM + oxytocin

Indications
-To augment labour
-To permit FSE
-To permit FBS
Timing of ARM
-No clear consensus
-Early ARM before 3-4cm dilated associated with reduced time until delivery
-Early ARM may increase risk of CS + chorio but evidence is conflicting. Some studies say reduced.
-Can be done prior to or after oxytocin started. Consider starting oxytocin if head high or cervix unfavourable
Comparison of ARM alone vs ARM + oxy
-More VB within 24hrs if ARM + oxy. RR
-Fewer instrumental deliveries if ARM + oxy
-No difference in CS rates, PPH, fever
-Poor maternal satisfaction with oxy cf prostaglandin (RR 53)

Discuss oxytocin use for IOL
-Types of protocol (1)
-Evidence around use (6)

Can have low dose and high dose protocols
Evidence around use
-MOH support DHBs designing own protocol
-No evidence for different protocols for multips and nulips
-No evidence for different protocols for augmentation vs IOL
-Limited evidence supports high dose oxy for shorted IOL time until delivery
-No evidence for maximum dose in women with CS
-Oxy started immediately post ARM associated with increased VB within 12 hrs, decreased maternal pyrexia, increased maternal satisfaction, increased active labour within 4 hrs

Discuss prolonged pregnancy
-Incidence (2)
-Aetiology (3)
-Risk factors (6)
-Maternal risks (5)

Incidence
-10-25% (Nice 17%)
-Can be reduced with correct EDD
Aetiology
-Majority unknown cause
-Anencephaly - where absence of fetal hypothalamus
-Defects in fetal production of hormones related to parturition
Risk factors
-Personal or family Hx
-Nulliparity
-Male fetus
-Obesity
-AMA
-Ethnicity - more common in Caucasian women
Maternal risks
-Increased instrumental delivery
-Increased dysfunctional labour
-Increased risk PPH
-Increased obstetric trauma
-Increased shoulder dystocia
-Increased CS delivery
-Increased NICU admission
-Increase risk SB

Discuss fetal dysmaturity syndrome -Associated with (4) -Characteristics (4) -Risks (7)

1. Associated with: -Chronic malnutrition -Placental insufficiency - seen as oligohydramnios -Increased rate of abnormal Fetal heart rate pattern -Increased meconium passage 2. Characteristics -Long thin body -SGA -Dry parchment like skin that is peeling -Absent lanugo 3. Risks -Hypoglycemia -Polycythemia -Perinatal asphyxia -Mec aspiration -Persistent pulmonary HTN -Seizures -Cerebral palsy

Discuss risks of still birth in post dates babies -Risk at 42 weeks -Risk at 43 weeks -Risk at 44 weeks -Risk for nullips -Risk for multips -Main causes of still birth postdates (4)

1. Risk at 42 weeks -2 x increase (Absolute risk 41-42 weeks 1.2 /1000) 2. Risk at 43 weeks -4 x increase (Absolute risk 42-43 weeks 1.9/1000) 3. Risk at 44 weeks -5-7 x increase (Absolute risk >43 weeks 6/1000) 4. Risks for nullips - increase expontially 5. Risk for multips 2 x increase and risk remains stable 6. Main causes for PD still birth -Intrauterine infection -Placental insufficiency -Oligohydramnios and cord compression with associated fetal hypoxia -Mec aspiration

Discuss management options for Postdates women (3 points)

1. Offer S&S after 39 weeks to reduce PD numbers 2. IOL after 41 weeks (NICE recommendation) 3. Expectant management -twice weekly clinical review, CTG, and LV -No evidence for dopplers -Poor evidence overall

Discuss the evidence for IOL for Post dates women (7)

1. Reduced perinatal mortality RR 0.26 2. Reduced stillbirth RR 0.24 3. Reduced CS rates RR 0.9 4. Reduced NICU admission RR 0.85 5. Reduced macrosomia RR 0.72 6. Reduced meconium aspiration RR 0.72 7. No clear evidence for reduction of neonatal birth trauma reduction or neonatal encephalopathy

Discuss the ARRIVE trial -Aim -Study design -Primary outcomes -Secondary outcomes

1. Aim To compare IOL at 39/40 with expected management in low risk primips for neonatal and maternal complications 2. Study design -RCT - multicentre USA -IOL method was centre specific 3. Primary outcome -Composite measure of perinatal death or severe perinatal complication (HIE, low APGAR, Resp support, ++) 4. Secondary outcome -CS rate

Discuss the results of the ARRIVE trial -Number of women recruited (1) -Results of primary outcomes (3) -Results of secondary outcomes (3)

1. Number of women recruited 3000 per group 2. Results of primary outcomes -4.3% vs 5.4% of perinatal outcomes in IOL vs EM groups RR 0.8 (NS) -EM group needed more resp support (SS) -All other measures of perinatal outcomes NS 3. Results of secondary outcomes -18% vs 22% CS in IOL vs EM groups RR 0.8 (SS) NNT 28 -Less HTN in IOL group 9% vs 14% RR 0.64 -Less CS hysterotomy extension

Discuss labour following Term PROM -Incidence of PROM -Likelihood of labouring within 24hrs -Likelihood of labouring within 48hrs

1. Incidence - 10% 2. Labour within 24hrs - 60% 3. Labour within 48hrs - 85%

Discuss the TERM PROM trial -Aim -Study design -Inclusion criteria

1. Aim To determine if IOL or EM is better in terms of neonatal infection and CS rate for term PROM with no evidence of fetal or maternal compromise To determine which form of IOL oxy vs Prostaglandin is better 2. Study design -Multi centre RCT -4 arms IOL oxy, IOL prostaglandin, EM (oxy IOL after 4 days), EM (prostin after 4 days) -Measured neonatal Infx by culture and WWC + clinical. Blinded. 3. Inclusion criteria -SROM >37/40 -Singleton and cephalic -No evidence of fetal or maternal compromise (mec liquor, chorio)

Discuss the Term PROM trial -Primary outcomes -Secondary outcomes

1. Primary outcomes -Definite or probable neonatal infection 2. Secondary outcomes -Maternal satisfaction with process -CS rates -Maternal and neonatal health outcomes

Discuss the TERM PROM trial -Number included in study -Primary outcome results -Secondary outcome results -Recommendations

1. Number included in the study -Approx 1250 in each arm (5000) 2. Primary outcomes -No difference between groups in neonatal infection or mortality 3. Secondary outcomes -IOL oxy vs EM oxy: Less chorio 4% vs 9%, neonatal abx, less NICU admissions, more satisfaction -IOL oxy vs all other option: faster time to active labour, shorter labour to all other groups, -No difference in CS rates 4. Recommendations -IOL (oxy or PGE2) or EM is a reasonable option given no difference in neonatal infection or CS rates

Discuss the TERM PROM trial -Number included in study -Primary outcome results -Secondary outcome results -Recommendations

Discuss the AFFIRM trial -Aim (1) -Study design (4) -Primary outcome (1) -Secondary outcomes (5)

1. Aim Investigated the impact of a RFM care package including education and timely delivery reduced still birth 2. Study design -Step wedge RCT in UK and Ireland of 33 hospitals -Not blinded -three periods pre intervention /wash out/ intervention -If RFM - scan, CTG, IOL after 37/40 if SGA, Recurrent RFM, Oligohydramnios, AbN CTG 4. Primary outcome -Still birth incidence after 24/40 5. Secondary outcomes -SB after 37/40 -CS and IOL rate -NICU admission -Fetal health parameters

Discuss the AFFIRM trial -Number included -Results

1. Number included 400 000 pregnancies 2. Results -No difference of SB between intervention and non-intervention RR 0.9 (NS) -No impact on SB at any gestation threshold -Increase in IOL and CS in the intervention group (SS) -Increase in NICU admissions in intervention group (SS)