Perinatal mortality and case fatality after placental abruption in Norway 1967-1991.

STUDY OBJECTIVE

To study national secular trends in Norway of perinatal mortality and case fatality to placental abruption (PA) and associations with cesarean section (CS).

DESIGN

A population based cohort study.

SETTING

The Medical Birth Registry of Norway.

PATIENTS

9,592 cases of placental abruption (PA) of a total of 1,446,154 births notified in Norway 1967-1991.

MAIN MEASURES

Comprehensive perinatal mortality (all stillbirths > or = 16 weeks of gestation and early neonatal deaths) and standard perinatal mortality (all stillbirths > or = 28 weeks of gestation and all early neonatal deaths). Case fatality rate.

MAIN RESULTS

From 1967 through 1991, the standard perinatal mortality rate due to placental abruption (PA) in Norway decreased from 2.5 per 1000 births (13.5% of all deaths) in 1967 to 0.9 (13.2%) in 1991. The comprehensive perinatal mortality rate due to placental abruption (PA) in Norway decreased from 3.2 to 1.7 per 1000. The proportion of all perinatal deaths due to PA increased from 11.4% in 1967-1971 to 217.0 in 1987-91 and decreased in all gestational age categories. Case fatality in PA with cesarean section (CS) was generally lower than in PA without CS, regardless of gestational age.

CONCLUSIONS

Placental abruption is an important cause of perinatal mortality in Norway. Our results are in favor of an active approach with frequent use of cesarean section, also at lower gestational ages. The decreasing case fatality rate by year of birth in all gestational age groups may be attributed to improved obstetric and perinatal care.