[CG] Induction of labour


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Induction of labour for Primigravida and Parous Women (excluding those with previous CS)

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The process of induction should only be considered when vaginal delivery is felt to be an option for delivery.  A Consultant Obstetrician should be involved in the decision making in induction of all high risk pregnancies. 

Some inductions are triggered by clinical events such as decreased fetal movements, PPROM, SROM> 36 + 6 WEEKS. See relevant guidelines.

Uncomplicated pregnancies should be offered induction of labour between 41+ 0 and 42 + 0 weeks (i.e. T+7 and T+14).

A membrane sweep should be offered – see separate guideline.

From 42 weeks, women who decline induction of labour should be offered increased antenatal monitoring consisting of at least twice – weekly cardiotocography and ultrasound estimation of maximum amniotic pool depth.   

Maternal request:

Induction of labour should not routinely be offered on maternal request alone. However, under exceptional circumstances (for example, if the woman’s partner is soon to be posted abroad with the armed forces), induction may be considered at or after 40 weeks. 

When planning induction of labour think about indication and aim for weekday delivery for Diabetics, BMI ≥ 40, Twins, severe underlying medical conditions, High anaesthetic risk, VBAC (ARM only) or any VBAC with Consultant sanctioned use of PG. If weekend delivery unavoidable ensure all relevant staff aware of patient. 

Method of IOL

Primigravida  and Parous Women (excluding those with previous CS)

  • Review Case Notes and establish plan
  • Confirm cephalic presentation and FH activity. If in doubt ultrasound by trained medical staff.
  • Prostaglandins should be used in preference to ARM and Syntocinon in both prims & parous women with intact membranes, regardless of their cervical favourability.
  • Dinoprostone (Prostin ®) 3mgs vaginal tablets is the induction agent of choice
  • If the cervix is favourable for an ARM after a single dose of Prostin ® an ARM should be performed, otherwise a further dose of Prostin ® should be given. Appropriately trained midwives can administer these.

Women who are not suitable for amniotomy after 2 doses of dinoprostone.

  1. Remember to check patient has not had previous treatment to her cervix (e.g. cold coagulation). Occasionally insertion of a digit through the cervix is required to break down adhesions caused by such treatment.

  2. A further 3mg of prostin - note that this is outwith the Manufacturer's recommendations but acceptable in GGC on basis of peer practice/consensus. This may be administered by a suitably trained midwife.
    Note  Amniotomy is usually possible if the cervix admits a finger. Examining a patient on a Labour Ward couch, with or without lithotomy position may facilitate this.

  3. Mechanical induction with a Foley's balloon catheter. Technique - a 12 Fg Foley's balloon is inserted aseptically through the cervical os and the balloon inflated with 10ml sterile sodium chloride 0.9% for inj.  and 30ml sterile sodium chloride 0.9% for inj. injected through the lumen into the extra amniotic space. The inflated balloon should be left in situ until the next day, or until the balloon falls out.

  4. If amniotomy is not possible then the patient should be discussed with a senior Obstetrician (Consultant or ST7) and depending on the reason for IOL, offered:
    a) 24 hours “rest” and then re-start prostaglandin.
    b) Caesarean Section
  • Amniotomy should be performed prior to commencement of Syntocinon infusion.

  • Oxytocin (Syntocinon ®) should not be started within 6 hours following administration of vaginal Prostaglandins.

Fetal surveillance and IOL

  • CTG facilities must be available.
  • Fetal wellbeing should be established immediately prior to administration of vaginal Prostaglandins by means of continuous CTG for 20 minutes.
  • Induction with Prostaglandins should only proceed if CTG is reassuring.
  • Fetal wellbeing should be observed by continuous CTG for 30 minutes following the insertion of vaginal Prostaglandins.
  • Following IOL with vaginal Prostaglandins, fetal wellbeing should be established once contractions are detected or reported or SROM occurs. This should be by initial CTG assessment and then intermittent monitoring in uncomplicated pregnancies. High risk pregnancies should have continuous CTG monitoring once regular uterine activity 
  • Where Oxytocin (Syntocinon ®) is used for induction or augmentation, continuous CTG monitoring should be used in all cases.

Women who decline IOL

Offer of induction declined from 42 weeks.

  • Initiate serial monitoring at 42 weeks in Day Care Unit
  • Measurement of single deepest pool of liquor and umbilical artery doppler
  • Twice weekly CTG
  • Senior Obstetric review

The above monitoring plan is “prognostic.” There is no evidence that monitoring can predict stillbirth in past date pregnancy and the patient must be informed about this. 

Advise delivery if monitoring abnormal.

Admissions procedure

  • All women should be admitted to the priming area on the day of Dinoprostone (Prostin ®) administration.
  • Checklist should be completed appropriately by the midwife in the low risk cases.
  • Confirm cephalic presentation. If in doubt – ultrasound by trained medical staff.
  • In high risk inductions the Middle Grade Obstetrician and Anaesthetist should be made aware of the relevant risks.
  • Anaesthetist should be alerted when high risk maternal conditions present. (See relevant list).
  • FBC should be taken if no sample within previous 4 weeks or if platelets <200.
  • Check Group B Strep status and have antibiotics prescribed if appropriate. (These should commence as soon as patient is in labour)
  • Healthy women with uncomplicated pregnancies should have vaginal Prostaglandins administered in the priming area. The ward staff should liaise with Labour Suite (LS) / Middle Grade Obstetrician regarding workload.
  • Women with recognised risk factors should be induced in an area appropriate to the particular risk after discussion with a Senior Obstetrician.
    • Previous CS
    • Recent APH
    • High parity ≥4
    • Any patient requiring a continuous CTG
    • AC <10th centile
    • Severe pre-eclampsia
    • SRM meconium not in labour
    • Twins
    • Severe asthma (previous hospitalisation or on oral steroids)
    • Oligohydramnios (deepest pool of liquor < 2cm)
    • Anaesthetic high risk patients
    • Any patients identified as high risk by a Consultant Obstetrician

Inductions on Antenatal Ward

  • Meals may be given as normal if CTG reassuring and not contracting regularly.
  • Appropriate analgesia should be offered.
  • Aim for transfer to LS by 8am the following morning for ARM.
  • Transfer to LS earlier if any concern regarding CTG or if labour becomes established (confirmed by cervical assessment).

Appendix on the Management of IOL Following Previous Caesarean Section (See VBAC policy)

Induction by any means is associated with an increased risk of uterine rupture. This risk is highest with PG induction.


  • Uterine scar of unknown type or upper segment scar
  • Placenta praevia
  • Fetal malpresentation
  • History of uterine rupture
  • Absolute cephalopelvic disproportion


  • Clinical discussion regarding the timing and method of IOL must take place at Consultant level after cervical assessment
  • A clear management plan including method of induction should be made and documented in the casenotes.
  • This management plan should take into account cervical findings
  • IOL in the presence of an unfavourable cervix requires careful consideration – appropriate alternatives may include elective Caesarean section or later review in anticipation of spontaneous labour or cervical ripening
  • The Middle Grade Obstetrician on-call should be aware of the patient’s presence on the labour ward
  • A venflon should be in place and blood sent for FBC and G&S IF Consultant has sanctioned use of vaginal PG,  Vaginal Prostaglandins (Prostin tablets 3mgs) should be administered at 10pm and the cervix reassessed by the Registrar at 6am.  One further dose of Prostin (3mgs) could then be given, but careful consideration of the clinical situation is essential
  • Difficult ARM is to be avoided
  • Syntocinon may be initiated following ARM, but should not be started within 6 hours of Prostin, as this may lead to uterine hypertonus. (Syntocinon should be prescribed by the Registrar on-call).
  • The use of Syntocinon should always be cautious (refer to Syntocinon and VBAC guidelines)
  • CTG should be commenced 20 minutes prior to assessment and continue for at least 30 minutes afterwards. Continuous EFM is indicated from the onset of uterine activity following ARM and during administration of IV Syntocinon
  • Adequate progress in labour should be confirmed by VE at least 4 hourly/or as indicated and advice sought if there is deviation from expected progress
  • The decision to deliver by emergency CS should be made at Consultant level
  • The casenotes should contain full and accurate documentation of events
  • This is a GUIDELINE – flexibility in individual cases is inevitable, but management decisions should occur at senior level where possible and be clearly documented.

Pre-labour ROM at Term (>37 weeks gestation) Following Previous CS:

If trial of vaginal delivery has been agreed:

  • Exclude malpresentation
  • Offer options as usual in pre-labour SROM, i.e Immediate IOL or IOL after 24 hours, in which case patient should remain as in-patient
  • Perform baseline VE prior to IOL
  • IOL method of choice is IV Syntocinon

MULTIGRAVIDA (no previous CS) – Low and high risk (flowchart)

Maximum 3mg Prostin each dose  (three doses total) in all cases (see text).

PRIMIGRAVIDA - Low and high risk (flowchart)

Maximum 3mg Prostin each dose  (three doses total) in all cases

Last reviewed: 29 August 2017

Next review: 31 July 2023

Author(s): Katie McBride

Version: 2

Approved By: Obstetrics Clinical Governance Group

Document Id: 562