Factors influencing delivery method in breech presentation

Background. To study factors influencing delivery method in breech presentation. Methods. Population based cohort study from The Medical Birth Registry of Norway, comprising all singleton deliveries in Norway, 1967-1994, 1,592,064 deliveries of which 45,921 (2.9%) were in breech presentation. Results. The proportion of cesarean section in breech presentation increased from 3.6 per 100 in 1969 to 58.8 in 1994. The relative risk for delivery by cesarean section in breech presentation compared to the nonbreech population increased from 2.0 (95% CI 1.5-2.7) in 1967 to 5.9 (95% CI 5.6-6.2) in 1994. It declined by maternal age, increased by gestational age and was lowest among mothers with urban residence. A negative association was observed between the annual number of births at the delivery department and the cesarean section proportion. However, during the observation period, the centralization of breech deliveries to the largest departments was reduced. Conclusions. Vaginal delivery in breech presentation was particularly observed in large delivery departments and among mothers with urban residence. Since experience and practical competence are prerequisites for successful vaginal delivery, this centralization seems justified. Further centralization of all breech presentation births should be pursued. However, preparedness as to vaginal delivery should be established also at the smaller units, eg by a routine providing periodical centralized training for obstetricians working in smaller institutions.