Fatores maternos e resultados perinatais no descolamento prematuro da placenta: comparação entre dois períodos , in singleton delivery with birthweight higher than 500 g and after 20 weeks of gestation. The following factors were analyzed: maternal age, previous obstetric history, prenatal care, premature rupture of membranes, obstetric and/or clinical intercurrent events, vaginal bleeding, uterine tonus, fetal anomaly, mode of delivery, hemoamnion and maternal complication (hysterectomy, uterine atony, disseminated intravascular coagulation, acute renal failure, and maternal death), and the perinatal results. Results: the rate of placental abruption was 0.78% (60 cases) in the period 94-97 (n=7692 deliveries), and 0.59% (51 cases) in the period 01-05 (n=8644 deliveries), without signifi cant difference. A signifi cant difference was observed between the periods 94-97 and 01-05 regarding mean number of previous gestations (3.5±2.4 and 2.6±1.8, p=0.04), patients without prenatal care (13.3 and 2.0%, p=0.03) and maternal intercurrences (38.3 and 64.7%, p=0.01). No signifi cant difference was observed related to vaginal bleeding, tonus abnormalities and perinatal results, between the periods, but a higher proportion of hemoamnion in 94-97 was found when compared to 01-05 (28.3 and 11.8%, p=0.03). Conclusions: in spite of obstetrical advances, maternal complications and perinatal results were similar in the analyzed periods. The severity and the unexpected results emphasize the importance of prevention and adequate control of associated factors, when this pathology is approached.