The portion of early rupture of the membranes among 521 premature births from 1962 to 1971 was 43.4%. The statistically sure effects of the early rupture of the fetal membranes to some irregularities in pregnancy and delivery on 214 premature births are reported, compared with 202 premature births without early rupture of the membranes. Twins are not considered. The therapeutic management of that time in the hospital consisted of staying in bed without tokolytics or antibiotics. After premature rupture of fetal membranes occured very often: irregular obstetrical presentation, hemorrhage and fever during labour, cesarean section and forceps delivery; the perinatal morbidity was increased. From that aspects for prophylaxis and therapy were deduced.