Table 1 Pilot trial outcomes and methods of assessment

Feasibility of delivering the intervention as planned

a. Participation rate of midwives attending the intervention delivery (training day) in the intervention arm, calculated as a percentage of all eligible midwives invited to attend

b. Feasibility of intervention delivery, calculated as the number of intervention sessions delivered with the planned number of midwives (six/session) in attendance at each session

c. Intensity of intervention delivery, calculated as the number of intervention sessions required to deliver the intervention to all recruited midwives in the intervention arm

d. Time required for intervention delivery, calculated for both intervention sites as the number of weeks between delivery of the first and last intervention session

e. Fidelity of intervention delivery following the initial pilot intervention session, calculated as the frequency of the delivery of the intervention as planned (i.e. all content delivered in the allocated time) measured by direct observation and video recording of the intervention sessions, and frequency of deviation from protocol

f Time taken to deliver intervention sessions, obtained from analysis of videos of each intervention delivery

Feasibility of recruitment and randomisation of sites, and recruitment of midwives and pregnant women

a. Rates of recruitment of sites

b. Achievement of randomisation

c. Rates of recruitment of midwives (to receive intervention and for data collection) and of pregnant women (for data collection)

Feasibility of collecting the outcome measures required for a definitive trial, and to prioritise which outcomes should be primary or secondary outcomes for a definitive trial

a. Rates of consent and attrition of midwives and pregnant women to provide questionnaire data at all time points:

i Midwives’ questionnaires at baseline (pre-intervention) and follow-up (3 and 6 months post-intervention)

ii Women’s questionnaires at baseline (pre-intervention at 20 weeks gestation)

iii Women’s questionnaires and weight measurements at follow-up (post-intervention at 12 and 36 weeks gestation, and 3, 6, 9 and 12 months postnatal)

b. Completeness of questionnaire data returned, calculated as percentage of missing data for each questionnaire section

c. Feasibility of using routine hospital data for pregnancy weight measurements, assessed by a clinical audit of electronic and handheld medical records for all participating women at baseline and follow up