on behalf of the ASSIST Study Team BACKGROUND: No new method of assisting vaginal birth has been introduced into clinical practice since the development of the vacuum extractor in the 1950s. The Odon Device is a new device that employs a circumferential air cuff over the fetal head to assist birth. In this study, the Odon Device has been used to assist vaginal birth for standard clinical indications. OBJECTIVE: This study aimed to investigate the clinical impact, safety, and acceptability of the Odon Device to women, their babies, and clinicians and to assess the feasibility of recruiting women to an interventional intrapartum research study. STUDY DESIGN: This is a nonrandomized, single-arm interventional feasibility study of the Odon Device for operative vaginal birth undertaken in a single maternity unit: Southmead Hospital, Bristol, United Kingdom. The Odon Device was used to assist birth in 40 women who required the birth to be assisted for suspected fetal compromise and/or prolonged second stage of labor. The primary clinical outcome was the proportion of births successfully assisted with the Odon Device, and the primary feasibility outcome was the proportion of eligible women who were approached and who agreed to participate. Neonatal outcome data were reviewed at day 28, and maternal outcomes were investigated up to day 90. RESULTS: Between October 2018 and January 2019, 298 of 384 approached, eligible women (77.6%) consented to participate. Of these women, 40 received the intervention-the use of the Odon Device. Birth was assisted in all cephalic (occiput anterior, occiput transverse, and occiput posterior) fetal positions, at all stations at or below the ischial spine and with or without regional analgesia. The Odon Device was effective in 19 of 40 cases (48%). Of the 40 births, 21 (52.5%) required additional assistance: 18 of 40 births (45%) were completed using nonrotational forceps, 1 of 40 births (3%) required rotational forceps, and 2 of 40 births (5%) required an emergency cesarean delivery. There was no serious maternal or neonatal adverse event related to the use of the device, and there was no serious adverse device effect. There were 4 devices (10%) that were ineffective because of a manufacturing fault. Furthermore, 39 of 40 women (98%) reported a high birth perception score. All practitioners were able to use the device as intended, although some steps in using the device were reported to be easier to perform (setup and deflation of air chamber) than others (application of the device and withdrawal of the applicator). CONCLUSION: Recruitment to an interventional study of a new device for operative vaginal birth was feasible; 78% of eligible women were willing to participate, often expressing an aspiration for an alternative to forceps and vacuum. The success rate of the Odon Device was lower than reported success rates of vacuum and forceps; however, in this study, the device had been used to assist birth for standard clinical indications. There was no significant maternal or neonatal safety...

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Background The Odon Device™ is a new device for assisted vaginal birth that employs an air cuff around the fetal head for traction. Assisted vaginal birth (AVB) is a vital health intervention that can result in better outcomes for mothers and their babies when complications arise in the second stage of labour. Unfortunately, instruments for AVB (forceps and ventouse) are often not used in settings where there is most clinical need often due to lack of training and resources, resulting in maternal and neonatal morbidity and mortality which could have been prevented. This is often due to a lack of trained operators as well as difficulties in the sterilisation and maintenance of AVB devices. This novel, single use device has the potential to mitigate these difficulties as it is single use and is potentially simpler to use than forceps and ventouse. All the studies of the Odon Device to date (pre-clinical, preliminary developmental and clinical) suggest that the Odon Device does not present a higher risk to mothers or babies compared to current standard care, and recruitment to intrapartum research exploring the device is feasible and acceptable to women. The first study in which the Odon Device was used in clinically indicated conditions (the ASSIST Study) reported a lower efficacy than those reported with established devices. The reasons need to be explored, specifically focussing on learning curve, the technique of the doctors using this new device and potential modifications to device design. A follow-on clinical study to further investigate the efficacy and safety of the Odon Device in its indicated use, the ASSIST II Study, is therefore being undertaken. Methods The primary feasibility outcome is study feasibility (recruitment and retention rates) whilst the primary clinical outcome successful vaginal birth completed with the Odon Device. Key secondary feasibility outcomes include participant withdrawal, compliance in data collection and acceptability of the device to women and operators. Secondary clinical outcomes include maternal, neonatal and device outcomes. Safety data will be reviewed following every birth exploring maternal, neonatal and device risks. Using A’Hern approach for sample size calculation, we aim to recruit 104 women requiring an assisted vaginal birth for a recognised clinical indication. Assuming an AVB success rate of 65% or more, a one-sided alpha risk of 5% and power of 90%. Discussion The data from the ASSIST II Study will provide the information required regarding acceptability, recruitment, outcome data collection, device design, technique of device use and operator learning curve in order to design a future randomised controlled trial of the Odon Device versus current modes of assisted vaginal birth. Trial registration ISRCTN registration: 38829082 (prospectively registered July 26, 2019)

BackgroundPostpartum haemorrhage remains a major cause of maternal mortality and morbidity worldwide. Active management of the third stage of labour reduces the risk of postpartum haemorrhage. Oxytocin and oxytocin/ergometrine are commonly used in the UK, with oxytocin/ergometrine being more effective at preventing moderate, but not severe, blood loss. Many guidelines specifically recommend using oxytocin for all vaginal births, as it is associated with fewer adverse events. However, a survey conducted by the Southmead Hospital Maternity Research Team revealed that 71.4% of UK obstetric units still routinely use oxytocin/ergometrine. Carbetocin is a newer medication that may be as effective but has fewer side effects. No studies have directly compared all three medications.MethodsThe IMox study aims to determine the most effective, acceptable and cost-effective drug for primary prevention of postpartum haemorrhage following vaginal birth. The IMox study is a prospective, multi-centre, double-blind, randomised trial directly comparing oxytocin, oxytocin/ergometrine and carbetocin given intramuscularly for the prevention of postpartum haemorrhage in the third stage of labour. The primary effectiveness outcome is the use of an additional uterotonic drug. Secondary effectiveness outcomes reflect maternal morbidity and mortality within the immediate postpartum period. Participant questionnaires and subjective reporting of side effects will be used to evaluate maternal acceptability. Maternal quality of life utilities will be collected antenatally, and on days 1 and 14 after birth to enable a cost-effectiveness assessment of each studied drug.Participants will be pregnant women planning a vaginal birth in six hospitals in England. Participants will be approached and invited to provide consent to participate from 20 weeks gestation until in established labour. A complete sample of 5712 participants (1904 per arm) providing data for the primary outcome will allow for a robust determination of efficacy between all three study drugs. Data will be collected until participants are discharged from the hospital and on postnatal days 1 and 14 regardless of location. All analyses will be on a modified intention-to-treat basis, and additionally repeated on a per protocol basis. Data collection commenced in Feburary 2015 and was completed in August 2018.DiscussionThis study is the first to directly compare oxytocin, oxytocin/ergometrine and carbetocin in the same population for the prevention of postpartum haemorrhage following vaginal birth. Furthermore, this study will be the first to directly compute health economic outcomes from such a three-way comparison. This study is limited to using short-term outcomes, and so will not provide evidence for important outcomes such as long-term maternal psychological well-being and time to next conception.Trial registrationClinicalTrials.gov, NCT02216383. Registered on 18 August 2014. EudraCT, 2014-001948-37. Registered on 23 September 2014. ISRCTN, ISRCTN10232550. Retrospectively registered...