Feasibility study protocol of a pragmatic, randomised controlled pilot trial: membrane sweeping to prevent post-term pregnancy-the MILO Study.

Background: Post-term pregnancy is associated with an increased risk of maternal complications, respiratory distress and trauma to the neonate. Amniotic membrane sweeping has been recommended as a simple procedure to promote the spontaneous onset of labour. However, despite its widespread use, there is an absence of evidence on (a) its effectiveness and (b) its optimal timing and frequency. The primary aim of the MILO Study is to inform the optimal design of a future definitive randomised trial to evaluate the effectiveness (including optimal timing and frequency) of membrane sweeping to prevent post-term pregnancy. We will also assess the acceptability and feasibility of the proposed trial interventions to clinicians and women (through focus group interviews).

Methods/design: Multicentre, pragmatic, parallel-group, pilot randomised controlled trial with an embedded factorial design. Pregnant women with a live, singleton foetus ≥ 38 weeks gestation; cephalic presentation; longitudinal lie; intact membranes; English speaking and ≥ 18 years of age will be randomised in a 2:1 ratio to membrane sweep versus no membrane sweep. Women allocated randomly to a sweep will then be randomised further (factorial component) to early (from 39 weeks) versus late (from 40 weeks) sweep commencement and a single versus weekly sweep. The proposed feasibility study consists of four work packages, i.e. (1) a multicentre, pilot randomised trial; (2) a health economic analysis; (3) a qualitative study; and (4) a study within the host trial (a SWAT). Outcomes to be collected include recruitment and retention rates, compliance with protocol, randomisation and allocation processes, attrition rates and cost-effectiveness. Focus groups will be held with women and clinicians to explore the acceptability and feasibility of the proposed intervention, study procedures and perceived barriers and enablers to recruitment.

Discussion: The primary aim of the MILO Study is to inform the optimal design of a future definitive randomised trial to evaluate the effectiveness (including optimal timing and frequency) of membrane sweeping to prevent post-term pregnancy. Results will inform whether and how the design of the definitive trial as originally envisaged should be delivered or adapted.

Trial Registration: ClinicalTrials.gov NCT04307199 . Registered on 12 March 2020.