CAUSES OF PRETERM BIRTHS UNDER 1500 G AND THEIR SIGNIFICANCE IN PERINATAL MEDICINE

305 preterm babies with birthweight below 1500 g were delivered at our centre between 1991 and 1994. Classification according to etiology sh ows that more than half (52.7%) of these deliveries had to be induced secondary to underlying fetal or maternal pathology. A more efficient tocolysis could have prevented up to one third of these deliveries (31 .4%). The main cause of each preterm delivery was defined according to Whitfield's etiological classification. In decreasing order of freque ncy we found hypertensive disorders of pregnancy, multiple pregnancy, preterm premature rupture of membranes, preterm labour and vaginal ble eding in the third trimester. The majority of these deliveries (88.6%) were prenatal referrals, reflecting widespread regionalization of obs tetric services in Switzerland. Nevertheless, 64 women (24.2%) with th reatening preterm labour before the 32nd week of gestation had to be d enied admission to our hospital because of shortage of neonatal intens ive care beds, or had to be transferred from our hospital to another o ffering perinatal facilities during the study period (1991-1994). Acut e lack of neonatal intensive care unit beds in Switzerland requires cl oser attention in the future.