Secular trends in peri- and neonatal mortality in breech presentation; Norway 1967-1994

Objectives. To assess secular trends in mortality rates in breech presentation in Norway and the effects of gestational age, birth defects and delivery method. Material and methods. The Medical Birth Registry of Norway 1967-1994, with 45,579 breech presentation births from 24 weeks of gestation onwards, with mortality rate comprising all stillbirths from 24 completed weeks of gestation and all neonatal deaths (extended peri- and neonatal mortality) as main outcome variable. Results. The extended peri- and neonatal mortality rate in breech presentation births declined during the study period from 9.2% in 1967-76 to 5.5% in 1977-86 and to 3.0% in 1987-94. The highest relative risk of mortality in breech presentation versus the total birth population was observed in intrapartum death and in mortality less than 24 hours after delivery. Stillbirth represented about half of the extended peri- and neonatal mortality throughout the study period. Also in infants with birth defects, the survival increased during the study period. The extended peri- and neonatal mortality was highest in vaginal deliveries, but decreased during the period, irrespective of delivery method. Conclusions. Probably due to improved obstetrical and neonatal care, mortality associated with breech presentation has substantially decreased. Increased focus especially on stillbirth, might be instrumental in further reducing the mortality associated with breech presentation.