Fransen 2017.

Methods	Multicentre, open, cluster‐randomised trial
Participants	Who: All multiprofessional obstetric staff from 24 units (12 intervention and 12 control) Number: 471 staff Proportion of eligible staff participating: 95%
Interventions	Intervention description: Multiprofessional obstetric team training focusing on crew resource management Control: No training Location: Simulation centre Delivered by: An obstetrician and communication expert drawn from the group of 10 experienced facilitators Length: 1 day Duration: Single session
Outcomes	Outcomes: Composite of obstetric complications, low Apgar, severe postpartum haemorrhage, large blood transfusion, embolisation, hysterectomy, trauma due to shoulder dystocia, eclampsia, hypoxic ischaemic encephalopathy, low Apgar and pH < 7.05, maternal mortality Follow‐up: 1 year
Population studied	Description: Women with a singleton pregnancy beyond 24 weeks gestation Number: Intervention 14,500 patients, control 14,157 patients
Funding Source	ZonMw, the Netherlands Organisation for Health Research and Development
Study Setting	Obstetric units in the Netherlands
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Units were randomly allocated by an independent researcher using a computer‐generated list.
Allocation concealment (selection bias)	Low risk	As above
Blinding of participants and personnel (performance bias) All outcomes	High risk	Open trial
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No specific mention
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Not mentioned specifically, but methods to minimise missing data discussed in detail
Selective reporting (reporting bias)	Low risk	Reported outcomes as per protocol
Other bias	Low risk	Addressed issues such as staff receiving existing training at the control sites in the protocol in an attempt to minimise bias