An RCT of a Synthetic Osmotic Cervical Dilator for Induction of Labour in Comparison to Dinoprostone Vaginal insErt

Induction of labour (where labour is started artificially) is traditionally carried out with a range of different drugs or by surgery (rupturing the membranes or 'waters'). Dilapan-S is a mechanical device, known as an osmotic cervical dilator, which provides an alternative to drugs or surgery. Thin rods of an absorbent material (no active drug present) are inserted into the neck of the womb (cervix) and, as they absorb fluid, they swell and mimic the natural process of 'ripening' (or preparing) the cervix. This initial process is important before contractions begin. Unlike drugs, Dilapan-S does not cause premature contractions that, when too frequent, may cause the baby to become distressed. The project will compare cervical ripening using Dilapan-S with the standard use prostaglandin drug. Women with a single pregnancy, who require induction of labour, and who are not considered high risk, will be invited to participate. Investigators hope to recruit 860 women from UK maternity units over 2 years. Participants will have an equal chance of being randomised to the drug, which is standard practice, or the cervical dilator. The speed in which labour commences, the mode of delivery and any side effects will be compared. Importantly, investigators shall also assess patient satisfaction and anxiety during the induction process, by asking participants to complete a short questionnaire about their experience before they go home after having their baby. If osmotic dilators are effective investigators expect NICE to consider them an option alongside other cervical ripening methods.

Prospective, Phase III, UK, Open, Multicentre, Superiority, Randomised Controlled Trial of a CE marked medical device and an Investigational Medicinal Product (CTIMP).

Potentially eligible patients will be identified by their obstetrician or midwife, based on the need for induction of labour. Once the decision to induce labour is made, women will be approached to participate in the trial and will be given a patient information leaflet (PIL) enclosed in the induction admission letter. Patients wishing to enter the trial will be confirmed for eligibility by an obstetrician. Prior to patients undertaking any trial-related procedures, informed consent will be obtained.

Participants will then be randomised in a 1:1 ratio to either 1) synthetic osmotic cervical dilator or 2) a 10-mg controlled-release dinoprostone vaginal insert. Randomisation will be provided by a computer generated programme. A research assistant discloses the nature of the assignment only after enrolment. Investigators have calculated that 860 patients (430 in each arm) will need to be recruited over a 2 year period. Given the nature of the intervention, the SOLVE trial will not be a blinded trial.

Full data collection will be conducted for those patients giving informed consent, from medical records. This will include baseline data, and details of mother and child at birth. Patients will also be asked to complete a maternal satisfaction questionnaire before they are discharged. There will be no further follow-up of patients post-discharge from care unless a Serious Adverse Event requires this. If the patient withdraws her consent during the study, data collection will be stopped. Only anonymised data will be entered into the Case Report Forms (CRFs) by the study team. Details of all patients approached about the trial will be recorded on the trial Screening Log, and fully anonymised copies returned to the trials office for review.

Eligibility Criteria:
Inclusion criteria

Women must meet the following criteria prior to initiation of IoL:

1. ≥ 16 years of age
2. Able to provide informed consent
3. Singleton pregnancy
4. Indication for IoL
5. Pregnancy ≥ 37.0 weeks (assessed as an agreed gestational age by ultrasound dating scan)
6. Living fetus with vertex presentation
7. Intact membranes

Exclusion criteria

1. Women already receiving oxytocin
2. Diagnosis of fulminant preeclampsia / eclampsia
3. Contraindication to DINOPROSTONE or DILAPAN
4. If DINOPROSTONE for IoL is non-compliant with local policy
5. Enrolled in other randomised controlled trials of an IMP or device for cervical ripening or induction of labour