[Differences in perinatal mortality between provinces: dependence on many factors].

The Dutch perinatal mortality rate is relatively high when viewed in a European perspective. There appear to be also substantial differences in perinatal mortality between provinces, large cities and even between neighbourhoods. Accumulation of obstetric risk factors as well as socioeconomic and urban risks seems to be involved as well. This should be taken into account in the process of risk selection to define a high risk population needing hospital care. In 85% of all cases of perinatal mortality, one or more of the following perinatal morbidities are present, designated as the 'Big 4': congenital abnormalities, preterm birth, intrauterine growth restriction and low Apgar score (< 7; 5 min after birth). Differences in perinatal mortality, the evaluation of organisational features of care and determinants like travel time from home to hospital should always be related to the case mix represented by this 'Big 4'.