Prenatal case histories and labours of 908 mothers who delivered prematurely at the University of Heidelberg, Department of Gynaecology and Obstetrics in Mannheim, between the years 1966-1971 were compared with a freely selected group of 782 mothers who delivered healthy mature infants with birth weights over 2500 g. (Premature infants -- under 2501 g; Stillborn infants -- under 2501 g and a minimum 35 cm crown-heel length). A tendency to premature delivery was observed in primipara, multipara with at least 4 previous deliveries, unmarried mothers, and in women with a preceding miscarriage or with closely spaced pregnancies less than 24 months apart. Bleeding during pregnancy, EPH-Syndrome, inadequate prenatal care, premature amnion rupture, abruptio placentae, pathological presentation and complications during labour were more frequently observed in mothers who delivered prematurely than those at full term. Histo-pathological changes of the placentas were found in 11,2% in cases of premature births as opposed to 3,6% in full term cases.