Induction of labour using the cook cervical ripening balloon

Warning

Scope

To formulate a standardised approach to the induction of labour with the cervical ripening balloon in NHS Borders Maternity Services.

Induction of labour is the most commonly performed obstetric intervention. It is required in around 26% of pregnancies when the risks of continuing the pregnancy outweigh the benefits. Some patients have contraindications to prostaglandins due to the greater risk of uterine rupture; this includes those patients with previous caesarean section and grand-multiparity. They have a disproportionally greater rate of repeat caesarean section due to the limited options available for IOL.

The Cook Cervical Ripening Balloon (CRB) is a silicone double balloon catheter with an adjustable-length malleable stylet. The Cook Cervical Ripening Balloon is indicated for mechanical dilation of the cervical canal when the cervix is unfavourable for induction.

Pharmacological agents have associated risk of hyperstimulation (3-20%), whereas the balloon induction does not cause significant uterine contraction or systemic side effects.

Studies have shown both methods are equally effective with CRB having a slightly shorter insertion to  delivery interval, a similar caesarean section rate, no increase in maternal infection rates and no adverse neonatal effects when compared to induction with prostin gel.

SOP adapted with the kind permission of NHS Lothian

The Cook balloon device

 Silicone double balloon catheter with stylet

  • One balloon in Uterus (inflating valve marked U – RED)
  • One balloon in Vagina (inflating valve marked V – Green)
  • A blue valve marked S for stylet insertion (some balloons may not have this)
  • Each balloon could be filled in with sterile water / saline up to maximum of 80 mls
  • Single use device supplied in sterile package

Indications

  1. Counselled re induction reasons and options, and agreeable to balloon induction 

  2. Patient requiring IOL with relative contraindication to prostaglandin and not suitable for ARM:
    • Previous Lower Segment Caesarean Section (x1)
    • Grand Multiparous (P≥ 4)
    • Previous precipitous labour following prostaglandin use with or without associated fetal distress

  3. Unsuccessful IOL with prostaglandins

Contraindications

  1. Non-cephalic fetal presentation
  2. Free/ ballotable head
  3. Multiple pregnancy
  4. Sepsis
  5. Active genital herpes infection
  6. Ruptured membranes
  7. Any contraindication to induction of labour

Criteria for Outpatient IOL with CRB

  • Lives within 40 min travel time of BGH
  • Has own transport
  • No maternal or fetal risk factors identified
  • Has mobile phone
  • Has another adult at home

NB for women planning VBAC – suitability for outpatient use of CRB must be a Consultant decision.

Who can insert it?

The CRB can be inserted by any healthcare professional (medical or midwifery) who has received the appropriate training

Booking and Admission procedure for CRB IOL

  • Assessment and suitability for CRB confirmed by senior medical staff and documented on badger.
  • Book into labour ward & Ward 16 diary for 18.00 hrs – device is fitted and patient returns the following morning or earlier if the balloon dislodges.
  • On admission, perform antenatal check
  • Full MEWS
  • Perform USS to Confirm cephalic presentation
  • Perform CTG
  • Contact CRB trained personnel and inform of the patient admission

Procedure

 Equipment required 

  • Sterile Cusco speculum (large with ratchet)
  • Sponge holder (Rampleys)
  • Sterile Gauzes swabs
  •  Sterile Gloves
  • Sterile aquagel (optional)
  • Sterile Galipot filled in with 200mls sterile water or sterile saline
  • 1 or 2 20ml leurlock syringes
  • Light source
  • Pre-packed CRB device

 Patient preparation

  1. Procedure discussed with patient and verbal consent obtained
  2. Place patient in lithotomy position (Not mandatory)
  3. Open the CRB pack and assemble the stylet if required
  4. Insert the speculum in vagina to fully visualise the cervix
  5. Clean the cervix with wet gauze

 Device placement

  1. Insert the device into the cervix and advance it until both balloons have entered the cervical canal (Aquagel can be used as lubricant)
  2. If the stylet is used then it should be withdrawn as soon as the 1st balloon is no longer in view
  3. Inflate the uterine balloon with 40 ml of water through the blue valve marked ‘U’ then pull the device back until the balloon abuts the internal os
  4. The vaginal balloon is now visible outside the external os. Inflate it with 20 ml of water through the green valve marked ‘V’
  5. Remove the speculum
  6. Add 20 ml water through valve U and 20 ml through valve V. Repeat to a maximum of 80mls in each balloon.
  7. If patient uncomfortable: reduce volume of fluid in vaginal balloon first
  8. Tape the proximal end of the catheter to the patient’s thigh
  9. If difficulty in insertion contact the on-call registrar for assistance.

Post insertion monitoring

  1. CTG for 30 minutes
  2. If normal, patient can go home and return 12 hours later to have it removed
  3. Can mobilise, eat and drink at leisure; should pass urine without difficulty
  4. If the patient goes home advise them to contact labour ward if reduced fetal movement/SRM/PV bleeding/regular painful contractions/pain/CRB falls out/urine retention.
  5. If urine retention: deflate the vaginal balloon to < 50 mls

 

Documentation

Please document on badger:

  • Date and time of insertion
  • Abdominal palpation and Bishop Score
  • Volume of fluid in each balloon
  • Patient experience of procedure.
  • Adverse event(s)
  • Plan of care; set time for review

CRB removal

Where

  • If inpatient, on ward 16
  • if outpatient on labour ward as plan will be for ARM

 When

  • After minimum 12 hours (but no longer than 24 hours).
  • Deflate sooner if SRM or regular painful contractions >= 4:10 minutes

Procedure

  • Check maternal observation
  • Deflate both balloons and remove the device
  • Perform a VE to assess Bishop Score and suitability for ARM and do a membrane sweep. 
  • Auscultate Foetal Heart for 1 minute. CTG is not required unless abnormal FH at auscultation.
  • Advise patient to mobilise

Suitability

If patient suitable for ARM

  • Liaise with LW for timing. If > 4hours waiting time, patient can go home and wait to be called in

 If Patient not suitable for ARM

  • To be reviewed by senior obstetrician

 Documentation

Please document on badger:

  • Date and time of removal
  • Abdominal palpation and Bishop Score
  • FH rate following removal
  • Adverse event(s)
  • Plan of care; set time for ARM or medical review

 

Training Record for Fitting Cooks Balloon (Midwifery Staff only)

  1. Watch the 3 training videos available from the following links: (load in Chrome)
    1. https://bcove.video/2Hdr76F
    2. https://bcove.video/2VkYVay
    3. https://bcove.video/2eBxPFv
  2. Observe Balloon fitting by Registrar/Consultant – discuss process with them, note order of inflation of balloons

  3. Insert 2 Cooks Balloons under direct supervision of Registrar/Consultant, complete competency record below
Date Patient ID Competency Observed (signature of Reg/Cons)
     
     

The process of removal is very similar to that of an indwelling catheter and therefore it is not necessary to have competence certified.

Editorial Information

Last reviewed: 05/02/2025

Next review date: 05/02/2028

Author(s): Gamme N.

Version: V2

Approved By: Gynaecology Department

Reviewer name(s): Wilson L, Guthrie K, Grieve C, Darlow K.