Table 2 Outcomes assessed in the OptiBreech 1 observational study

1.Trial feasibility

a.Number of sites that opened and recruited as planned

b.Source of participant referral

c.Mean and standard deviation recruitment per month across all sites

d.Attrition, defined as women who requested a planned caesarean birth following enrolment

2.Implementation feasibility

a.Proportion of vaginal breech births attended by a professional who had completed OptiBreech training

b.Proportion attended by a professional who met the full proficiency criteria

3.Fidelity — Care provided according to OptiBreech training [24, 36]

a.Proportion of vaginal breech births occurring with upright maternal positioning

b.Encouragement of maternal movement and effort prior to hands-on assistance

c.Less than 5 min between birth of foetal pelvis and birth of the aftercoming head

d.Less than 7 min between ‘rumping’ (anus and both buttocks visible) and birth of the aftercoming head

e.Initiation of resuscitation (if required) with umbilical cord intact

4.Costs

a.Time spent on-call to deliver service

b.Cost to achieve full proficiency criteria, assuming no prior experience

5.Safety

a.Proportion of neonates admitted to higher-level care immediately following birth

b.Combined perinatal mortality or severe morbidity

c.Severe unexpected adverse events

6.Effectiveness

a.Mode of birth

b.Diagnosis prior to or during labour

c.Attempt at external cephalic version prior to planned VBB

d.Reasons for caesarean birth