Cervical Ripening Balloon in Induction of Labour at Term
Condition: Pregnancy
Study type: Interventional
Phase: Phase 4

Summary: 
      About 1 in 6 deliveries in KKH are induced with prostaglandins. Inpatient induction can be a
      lengthy process especially when cervical priming is required. Although mechanical method of
      induction of labour (IOL) is established, its use in Singapore is uncommon. Systematic
      reviews comparing mechanical method against pharmacological and surgical IOL showed that
      mechanical method has similar efficacy with lower risk profile. As IOL is a common obstetric
      procedure, a revisit on the techniques is warranted. A multi-centre randomised controlled
      trial concluded that both cervical ripening balloon and prostaglandin are effective and
      complementary methods for IOL in uncomplicated singleton pregnancies, but did not examined
      the effects of pain.

      The investigators propose to evaluate the adverse events in the 12 hours after CRB or 1st
      prostaglandin insertion, its efficiency in term singleton IOL in Singapore context and test
      the acceptability of women in Singapore in using the CRB as an alternative method of
      induction of labour while using a non-incremental balloon filling regime. Currently, there is
      no efficient method of induction that can be used safely in an outpatient setting. Through
      this study, the investigators hope to show that there are no major adverse events in the 12h
      after patients are induced with CRB, this potentially supports outpatient IOL with CRB which
      can reduce hospitalisation and medical costs. A non-incremental balloon filling regime will
      decrease time delays and may increase patient satisfaction during its use in induction of
      labour.
    

Detailed description: 
      This is a prospective cohort randomised controlled trial conducted at the KK Women's and
      Children's Hospital (KKH) and University Malaya Medical Centre (UMMC).

      NICE guidelines on induction of labour defined uterine hyperstimulation as contractions more
      than 5 in 10 mins for more then 20 mins or contractions lasting more than 2 mins in duration.
      A retrospective study involving prostaglandin induction of labour showed that
      hyperstimulation occurred in 5.8% of cases. The sample size is calculated based on a 4.8%
      reduction in hyperstimulation in all induction of labour by CRB. At a level of significance
      of 5%, 80% power, 200 patients in each arm is required. Preliminary study by Tan TL et al had
      a dropout rate of 4.6%. Hence the proposed sample size is 420.

      The investigators plan to collaborate on a multi-centre trial with the University Malaya
      Medical Centre. In which, each centre will recruit 210 patients for the study.

      Randomization of the participants is achieved with third party sealed envelope allocation.
      210 envelopes containing CRB allocation and another 210 identical envelopes containing
      prostin allocation will be prepared by a third party. The 420 envelops will be shuffled
      according to a computer randomisation code after sealing and labelled with a randomization
      allocation number from 1 to 420. The 210 envelops will then be handed to the each centre's
      PI, and will be kept in the clinical store on labour ward together with the stock of CRB and
      prostin.

      Unfortunately, it is not possible to blind the allocation to the investigator or the patient.
      The investigator however has no part in observing any adverse events, the CTGs should be
      interpreted by the attending clinician and vet by team to avoid missing abnormal CTG. The
      patient herself will have to report contractions and pain scores and satisfaction scores with
      validated standard pain and satisfaction assessment tools to minimise the potential bias. The
      allocation will also be omitted from the database so as to blind the analyst in order to
      prevent manipulation.

      There will be no additional clinic visit or labour ward admission required by the study. The
      potential patient receiving subsidized obstetric care who require elective IOL at term will
      be will be identified by doctors and clinical research coordinator in the subsidized clinic
      or labour ward or obstetric subsidized wards, and screened accordingly with inclusion
      criteria and exclusion criteria.

      Inclusion criteria: Pregnant women aged 21 - 40 years old, singleton pregnancy, no major
      fetal anomaly, planned induction of labour at 37+0 weeks to 41+6 weeks gestation, vaginal
      delivery is appropriate, patient able to give informed consent to participate in the trial

      Exclusion criteria: Spontaneous labour at start of planned induction, Bishop score <6 and
      cervical dilatation >=3 cm at start of induction, confirmed rupture of membrane, abnormal CTG
      at start of induction, caesarean section delivery is indicated, scarred uterus such as
      previous caesarean section, malpresentation in labour, patient withdraw consent to
      participate in the trial. Latex allergy, severe asthma and glaucoma.
    

Intervention name(s): Cervical Ripening Balloon; Prostin
Intervention type(s): Device; Drug
Intervention description(s): Cook® Cervical Ripening Balloon with Stylet Order number G19891 Reference Part Number J-CRBS-184000 Catheter (Fr) 18.0 Length (cm) 40 Balloon Volume (mL) 80; Prostin E2 vaginal tablets contain the active ingredient dinoprostone, which is a naturally occuring female hormone also known as prostaglandin E2. Prostaglandins are involved in naturally starting labour. Dose of Prostin is 3 mg vaginally.
Other intervention name(s): Prostin E2 vaginal tablets
Intervention MeSH terms: Dinoprostone
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment