Inability to recruit more women because of the COVID-19 and staffing/resources issues

The aim of this study is to compare three different regimens for continuation of induction of labor after no spontaneous or artificial rupture of membranes could be achieved after first 24 hours post-insertion of Dinoprostone

This randomized study will be carried out at delivery suite in Warwick Hospital after eligible women have been informed of the study when booked for induction of labor and provided with the study information leaflet

When attending for induction of labor on delivery suite, an informed consent will be obtained then all women will have a cardiotocogram (CTG) performed initially and will be assessed by vaginal examination and Bishop score recorded at insertion of first slow-release pessary (Propess®10 mg Dinoprostone; CTS, UK), which will be inserted high into the posterior vaginal fornix. Assessment and insertion of pessary will be done by an experienced obstetrician or a senior midwife

All women will be given the required care and support as per the local protocols and guidelines

Women will be excluded from the study within the first 24 hours of induction of labor in the following conditions:

• Women with abnormal or non-reassuring CTG needing intervention.
• Women needing tocolytic use.
• Women needing removal of the Dinoprostone pessary.
• Women needing emergency Caesarean section.
• If spontaneous rupture of membranes occurs.
• If artificial rupture of membranes is achievable after the first 24 hours of induction of labor (Bishop score 5 or more)
• If woman withdraws her consent to continue as a part of the study.

After 24 hours from insertion of the first Dinoprostone pessary, women will be reassessed and a total of 330 women with Bishop score less than 7, will be randomly assigned to one of three intervention groups by a pre-formed computer-generated random list and randomization put in sealed opaque envelopes kept in a locked secure area on delivery suite.

Intervention groups will be as follows:

Group 1 (110 women):

Women will have the initial slow-release Dinoprostone pessary left in place for six more hours (total of 30 hours in place) then removed followed by vaginal assessment 48 hours after the start of labour induction and insertion of a second slow-release pessary if required (Currently Propess® is not licensed to be repeated as a second dose. However, there is a consensus that, the dose may be repeated after a consultant review and an informed verbal consent as per SWH 00190 Induction and Augmentation of the First and Second Stage of Labour Management Guideline, 2012).

Group 2 (110 women):

Women will have the initial slow-release Dinoprostone pessary removed followed by insertion of quick-release Dinoprostone tablet (Prostin® 3 mg Dinoprostone vaginal tablet; Pfizer, UK) high in the posterior vaginal fornix immediately after removal of the slow-release pessary. The tablet will be left for 6 hours followed by vaginal reassessment and insertion of a second tablet if ARM is still not achievable.

Group 3 (110 women):

Women will have the initial slow-release Dinoprostone pessary removed followed by insertion of 1-5 Osmotic cervical rods (Dilapan-S® Aquacryl hydrogel rod; HPSRx Enterprises, USA) by a senior obstetrician or a midwife into the cervical canal, immediately after removal of the slow-release pessary using a vaginal speculum and a holder. The rods will be left for 12-24 hours.

For all participants, after achieving spontaneous or artificial rupture of membranes, the local protocol for intrapartum care will be followed and after delivery, the women will be asked to fill in a patient's satisfaction questionnaire about the process of induction, care given and being a part of the study

Inclusion Criteria:

• Women booked for induction of labor at 37 to 42 weeks gestation
• Viable singleton pregnancy.
• Cephalic presentation.
• Intact membranes.
• No previous Caesarean section.
• No antenatal fetal concerns (Fetal growth restriction (FGR), small for gestational age (SGA), impaired Doppler, oligohydramnios, non-reassuring/abnormal CTG).

Exclusion Criteria:

• Pregnancy less than completed 37 weeks or more than 42 weeks.
• Multiple pregnancy.
• Intrauterine fetal death.
• Non-cephalic presentation.
• Pre-labor rupture of membranes
• Previous one or more Caesarean sections.
• Antenatal concerns regarding fetal well-being (FGR, SGA, impaired Doppler, oligohydramnios, non-reassuring/abnormal CTG).
• Non-reassuring or abnormal CTG on admission to labor ward