Study design, participants
For this retrospective register study, primiparous parturients with
spontaneous vaginal delivery at term (gestation week ≥37+0) were
included and divided into two groups depending on their EA status
(yes/no). Multiple pregnancies were excluded. These criteria were
applied to keep the study population as homogenous as possible, because
the National Birth Registry contains limited information on the medical
condition of each individual. Antepartum intrauterine foetal demise
(IUFD) were excluded for analysis of primary and secondary objectives.
No parturients or patients were involved in the planning and design of
the study. Hospitals were divided into four categories: (1) hospitals
with less than 500 deliveries per year, (2) hospitals with
>500 deliveries per year, (3) Perinatalcentre 2, defined as
specialised centre for obstetric cases with paediatric in-house services
for 24 hours, (4) Perinatalcentre 1, defined as specialised centre for
complex obstetric cases with paediatric in-house services for 24 hours
including a neonatological intensive care unit, a paediatric surgery
department and radiology particularly trained for foetal diagnostic.