OBJECTIVES: The aim of this study was to assess perinatal risk factors and the survival of the very preterm infant in comparison with birth beyond 32nd birthweek, as well as health care utilization by mothers and infants in the Northern Health Region of Sweden. DESIGN: A population-based study was designed of all children (66,646) born in the Northern Health Region of Sweden during 1991-1996 and registered in the Swedish Medical Birth Registry. METHODS: Maternal and perinatal factors of infants born very preterm, that is, at