The centralisation of high risk deliveries in perinatal centres has be
come standard practice in most developed countries over the last 20 ye
ars. The goal of this study was to assess to which extent this practic
e has been implemented in Switzerland as well. In addition, we compare
d standard morbidity outcome measurements between outborn and inborn i
nfants, as well as the frequencies of postnatal interhospital transfer
s. Methods: All infants born alive either below the 32nd week of gesta
tion, weighing less than 1500 g, or who required assisted ventilation
before the 44th week of corrected gestational age were entered in a pr
ospective epidemiological survey (Swiss minimal neonatal data set) if
they had been admitted to a neonatal intensive or intermediate care un
it. We analysed the data derived from infants born between 1 January a
nd 31 December 1996. Results: 86% of the 720 infants of less than 32 w
eeks gestation and/or less than 1500 g (group 1) were born in a perina
tal centre, whereas only 27% of the 508 infants greater than or equal
to 32 weeks gestation and greater than or equal to 1500 g who required
assisted ventilation (group 2) were inborn. In group 1 outborn infant
s had a higher risk for pulmonary hypertension (odds ratio 3.7, 95% co
nfidence interval 1.4 to 10.0), for hyperechogenic leucomalacia (odds
ratio 2.7, CI 1.3-5.4), for necrotising enterocolitis (odds ratio 2.5,
CI 1.1-5.7). The frequencies of postnatal interhospital transfer were
the following for group 1 and 2: once 35% vs. 52%, twice or more 10%
vs. 31%. Conclusion: 720 infants below 32 weeks gestation and/or <1500
g were admitted to neonatal units in 1996 which corresponds to 0.86%
of all liveborn infants in Switzerland. Fourteen percent of these infa
nts were outborn with a high morbidity. Of the 508 larger and older ne
w-born infants who required assisted ventilation (0.62% of all livebor
n infants in Switzerland), 73% were outborn. It is speculated that imp
roved prenatal identification of risk factors and prenatal transfer co
uld further reduce the morbidity of these two populations of new-born
infants.