[The breakthrough series on Cesarean section].
BACKGROUND: The "breakthrough series" on caesarean section was organised in Norway in 1998/99 in response to professional concerns about rising caesarean section rates and the public debate about the topic. The aim was to gain more information and to reduce the inter-hospital variation of caesarean section rates. MATERIAL AND METHODS: Detailed information about 3000 caesarean sections (70% of all caesarean sections in Norway during the study period of 7 months) was collected. Twenty-four departments participated and were involved in a quality-improvement process. RESULTS: In 1998 the caesarean section rate among the participating departments was 13.5% (inter-hospital variation 8.6% to 20.4%). In 2002 the rate was 15.7% (inter-hospital variation 11.0%-24.5%). The most frequent indications were fetal stress, prolonged labour, previous caesarean section, breech presentation and maternal request. Of the women with a previous caesarean section, 45.5% had a new caesarean section in their next pregnancy. Complications occurred in 21% of all procedures; risk factors were general anaesthesia, low gestational age, fetal macrosomia and degree of cervical dilation. INTERPRETATION: The project highlighted quality improvement work and interdisciplinary working processes and led to more knowledge about caesarean section. The inter-hospital variation was unchanged four years after the project.