Main findings
Our main finding was that most of the steep rise in the caesarean delivery rate, which increased from about 19% to 30% between 1989 and 2016, could be attributed to changes in maternal characteristics of the obstetric population. Fifty-six percent of the rise was explained by changes in maternal age, body mass index, maternal history of previous caesarean delivery, and parity. In other words, the caesarean delivery rate was expected to increase from 19.1% to 25.3% over the time period studied had there been no changes in obstetric practice whatsoever. The management of malpresentation, multiple gestation, and preterm birth explained 10% of the rise in the caesarean delivery rate, and the exclusion of some ‘newer’ indications for planned (pre-labour) caesarean delivery resulted in 78% of the rise in caesarean deliveries being explained. The impact of planned caesarean delivery by maternal choice alone was minimal.