Table 1.

The theoretical framework

	Variables	Instrument
Proximate indicators of ‘supportive care during labour’	Attendance of midwives	Time documentation tool
	Workload of midwives
	Outpatient care
	Supportive procedures by midwives	Birth documentation tool
	Attendance of a midwifery student	Time documentation tool
	Attendance of an obstetrician
	Shift changes
	Satisfaction with the presence of midwives	Postal questionnaire eight weeks postpartum
	Partner support helpful	Postal questionnaire eight weeks postpartum
		(three scales from BBCI)
	Midwife-led care	Birth documentation tool
	Hospital	Time documentation tool
	Admission during daytime	Time documentation tool
	Birth during daytime	Time documentation tool
Parturient-specific variables	Parity	Hospital-based information system
	Length of stay	Time documentation tool
	Epidurals and analgesia	Birth documentation tool
	Induction of labour
	Oxytocin usage
	Newborn weight	Hospital-based information system
	Childbirth preparation class	Postal questionnaire postpartum
Socio-demographic variables	Health insurance	Hospital-based information system
	Age
	Income	Willingness-to-pay questionnaire in pregnancy
	Education
	Partnership