Mechanical Dilation of the Cervix in a Scarred Uterus

NCT ID: NCT03471858

Last Updated: 2025-12-15

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 44 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2019-08-29
• Study Completion Date: 2025-08-16

Brief Summary

To determine if mechanical labour induction can offer a safer and effective alternative to prostaglandins to women with previous caesarean section attempting trial of labour after caesarean (TOLAC).

Detailed Description

There is good evidence to show that induction of labour with a transcervical balloon compares favourably with the use of prostaglandins.The cervical balloon works by softening & stretching the cervix mechanically & stimulates the release of endogenous prostaglandins.

When compared with prostaglandins, meta-analysis have shown that for TCB induction, there is no significant different in caesarean section rates (27% vs 25%) with a reduced risk of hyperstimulation with fetal heart rate change (0.4% vs 3%). Further, when compared against induction with misoprostol, induction with a Foley catheter balloon was found to have a lower rate of caesarean section for a non-reassuring fetal heart rate (RR 0.54, 95% CI 0.37-0.79) and a fewer vaginal instrumental deliveries (RR 0.74, 95% CI 0.55-0.95) [41]. One randomized controlled trial of 824 women with no previous caesarean section comparing foley catheter balloon with a prostaglandin E2 gel demonstrated no difference in caesarean section rates & 2 cases of uterine rupture or perforation in the prostaglandin E2 arm but not in the foley catheter balloon arm. Another study involving 1859 women comparing foley catheter balloon with oral misoprostol showed no difference in caesarean section rates or complications. It was, however, noted that induction with foley catheter balloon more likely required oxytocin induction at 80.3% vs 68.4% for misoprostol.

While there were earlier concerns of an increase in infectious morbidity when using mechanical induction of labour due to the presence of a foreign body, more recent RCTs & meta-analysis have shown that there is no significant increase.

One of the main concerns for induction of labour in patients with a previous uterine scar is an increased risk of uterine rupture. One observational study of 20,095 women quoted a risk of uterine rupture in spontaneous labour to be 0.52% & in prostaglandin-induced labour to be 0.77%. Another observational study involving 33,699 women quoted a risk of 0.4% and 1% respectively. While there are also studies which suggest that there is no significant increase in the rate of uterine rupture, many professional bodies have discouraged prostaglandin-induction in women with previous scars.

Due to lower levels of hyperstimulation that could lead to fetal distress or uterine rupture, trans cervical balloon induction has found itself as a possible, safer means of induction of labour for women who are keen for vaginal birth after caesarean and are agreeable with induction. Most RCTs were small in size & did not demonstrate any uterine rupture or dehiscence. However, 2 retrospective cohort studies involving a size of 2479 & 208 women respectively showed a uterine rupture rate of about 0.5%. trans cervical balloon induction appears to be a safe method for inducing consenting women keen for vaginal birth after caesarean and this study will contribute towards this body of evidence.

Conditions

Pregnancy Related; Labor Complication; Cesarean Section; Dehiscence

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

Cervical Balloon

Transcervical 2-way 18 French (18F) single balloon Foley catheter, applied using a sponge-holding forceps into the cervical canal with the balloon inflated to a minimum of 30ml and maximum of 60ml with sterile water or saline \[1\]. This will be administered once during the study and will be retained for a maximum of 12 hours within the 24 hour study period.

Group Type: ACTIVE_COMPARATOR

Cervical balloon

Intervention Type: DEVICE

To assess if a cervical balloon catheter (foleys catheter) for mechanical induction of labour is comparable to prostaglandin usage for induction of labour in women who have had a previous caesarean section.

Prostaglandin

Prostaglandin E2 (Prostin®) 3mg tablet, placed high in the vaginal fornix. This will be administered per vaginum once in the first 6 hours; a second dose is administered at the discretion of the clinician / clinical team 6 hours after the first pessary, for a cumulative total of 6mg within the 24 hour study period.

Group Type: ACTIVE_COMPARATOR

Prostaglandins

Intervention Type: DRUG

Prostin will be used in the control arm.

Interventions

Cervical balloon

To assess if a cervical balloon catheter (foleys catheter) for mechanical induction of labour is comparable to prostaglandin usage for induction of labour in women who have had a previous caesarean section.

Intervention Type: DEVICE

Prostaglandins

Prostin will be used in the control arm.

Intervention Type: DRUG

Other Intervention Names

Foley Balloon Catheter; Prostin

Eligibility Criteria

Inclusion Criteria

• Female ≥ 21 years of age at booking visit
• 1 previous uncomplicated lower segment caesarean section (CS)
• Aiming for TOLAC
• Written informed consent (and assent when applicable) obtained from subject or subject's legal representative and ability for subject to comply with the requirements of the study
• Singleton pregnancy
• Gestational age >37 weeks
• Understands risk of TOLAC
• Eligible for induction of labour for the standard obstetric indications, including post-date or post-term pregnancies at 40-41 completed weeks of gestation
• Unfavourable Bishop's Score ≤ 5 requiring cervical priming
• Previous uterine surgery, including simple myomectomy, where there is no contraindication to TOLAC
• Reactive CTG pre-induction
• Ruptured membranes

Exclusion Criteria

• Refusal to participate
• Women with 2 or more previous CS
• Previous classical or lower segment vertical incision, or inverted T or J incision in the previous caesarean delivery
• Previous uterine surgery with contra-indication to future TOLAC
• Maternal contraindication for vaginal delivery
• Fetal contraindication for vaginal delivery or major fetal abnormality
• Malpresentation or cord presentation
• Placenta praevia <20mm from internal os
• Chorioamnionitis
• Antepartum haemorrhage of undetermined origin AND deemed a contraindication for TOLAC
• Suspected fetal macrosomia (estimated weight on ultrasound >4kg) AND deemed a contraindication for TOLAC
• Congenital uterine abnormality
• Multifetal pregnancy
• Latex allergy or poorly-controlled asthma

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 50 Years
• Eligible Sex: FEMALE
• Accepts Healthy Volunteers: Yes

Sponsors

Department of Obstetrics and Gynaecology, National University Hospital

UNKNOWN

Sponsor Role: collaborator

Yong Loo Lin School of Medicine

OTHER

Sponsor Role: collaborator

National University Hospital, Singapore

OTHER

Sponsor Role: collaborator

National University of Singapore

OTHER

Sponsor Role: collaborator

Ministry of Health, Singapore

OTHER_GOV

Sponsor Role: lead

Responsible Party

Soe-na Choo

Medical Officer

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

National University Hospital, Singapore

Singapore, , Singapore

Countries

Singapore

References

Choo SN, Kanneganti A, Abdul Aziz MNDB, Loh L, Hargreaves C, Gopal V, Biswas A, Chan YH, Ismail IS, Chi C, Mattar C. MEchanical DIlatation of the Cervix-- in a Scarred uterus (MEDICS): the study protocol of a randomised controlled trial comparing a single cervical catheter balloon and prostaglandin PGE2 for cervical ripening and labour induction following caesarean delivery. BMJ Open. 2019 Nov 6;9(11):e028896. doi: 10.1136/bmjopen-2019-028896.

Reference Type: DERIVED

PMID: 31699720 (View on PubMed)

Other Identifiers

2018/00248

Identifier Type: -

Identifier Source: org_study_id