Feasibility and design of a trial regarding the optimal mode of delivery for preterm birth: the CASSAVA multiple methods study.

BACKGROUND

Around 60,000 babies are born preterm (prior to 37 weeks' gestation) each year in the UK. There is little evidence on the optimal birth mode (vaginal or caesarean section).

OBJECTIVE

The overall aim of the CASSAVA project was to determine if a trial to define the optimal mode of preterm birth could be carried out and, if so, determine what sort of trial could be conducted and how it could best be performed. We aimed to determine the specific groups of preterm women and babies for whom there are uncertainties about the best planned mode of birth, and if there would be willingness to recruit to, and participate in, a randomised trial to address some, but not all, of these uncertainties. This project was conducted in response to a Heath Technology Assessment programme commissioning call (17/22 'Mode of delivery for preterm infants').

METHODS

We conducted clinician and patient surveys (

RESULTS

Planned sample size and data saturation was achieved for all groups except for focus groups with participants, as this had to be curtailed because of the COVID-19 pandemic and data saturation was not achieved. There was broad agreement from parents and health-care professionals that a trial is needed. The clinician survey demonstrated a variety of practice and opinion. The parent survey suggested that women and their families generally preferred vaginal birth at later gestations and caesarean section for preterm infants. The interactive workshop and Delphi consensus process confirmed the need for more evidence (hence the case for a trial) and provided rich information on what a future trial should entail. It was agreed that any trial should address the areas with most uncertainty, including the management of women at 26-32 weeks' gestation, with either spontaneous preterm labour (cephalic presentation) or where preterm birth was medically indicated. Clear themes around the challenges inherent in conducting any trial emerged, including the concept of equipoise itself. Specific issues were as follows: different clinicians and participants would be in equipoise for each clinical scenario, effective conduct of the trial would require appropriate resources and expertise within the hospital conducting the trial, potential participants would welcome information on the trial well before the onset of labour and minority ethnic groups would require tailored approaches.

CONCLUSION

Given the lack of evidence and the variation of practice and opinion in this area, and having listened to clinicians and potential participants, we conclude that a trial should be conducted and the outlined challenges resolved.

FUTURE WORK

The CASSAVA project could be used to inform the design of a randomised trial and indicates how such a trial could be carried out. Any future trial would benefit from a pilot with qualitative input and a study within a trial to inform optimal recruitment.

LIMITATIONS

Certainty that a trial could be conducted can be determined only when it is attempted.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN12295730.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in

Around 60,000 babies are born preterm each year in the UK. We do not know what the safest mode of birth is for these babies. Birth options include a vaginal birth or a caesarean section (which involves an operation for the mother). Normally, the ideal way to find out what clinical options are best is to carry out a ‘randomised trial’ in which participants are allocated to a particular treatment group (in this case, vaginal birth or caesarean section) by chance. It is not clear if women who have their babies preterm would want to take part in such a trial or that the clinicians looking after the women would be happy to ask them to, as previous trials have failed to recruit sufficient participants. The purpose of the CASSAVA research project was to find out what people think is the best and safest method of delivering preterm babies, their views on doing a research trial and what sort of research trial could be carried out. We conducted a survey asking clinicians and women their views. We gathered clinicians and women together to discuss and agree the key questions for a trial to answer. We then developed a protocol (plan) for a possible trial. Using this trial protocol, we conducted telephone interviews with clinicians, asking them if they would be willing to be involved and if they would be willing to ask pregnant women to participate. We also conducted focus groups with women, using a vignette (storyboard) about a possible trial. We found that there is a lot of uncertainty about the best way for preterm babies to be born. Clinicians and women broadly agreed that it would be good to resolve this uncertainty through a trial. We were able to identify some areas of the greatest uncertainty where clinicians and women would consider participating in a study. We gained a lot of useful information about how we could best set up a trial and support clinicians and women to get involved.