Conclusion
Much of the increase in the caesarean delivery rate between 1989 and 2016 is explained by changes in maternal demographics and history of caesarean delivery and a significant proportion is explained by changes in the route of delivery for multiple gestation, malpresentations, and preterm births. Planned caesarean delivery for maternal choice had minimal impact.
Disclosure of interests The primary author was supported by an Early Career Fellowship grant from the Australian Government National Health and Medical Research Council whilst conducting this research.
Contribution to authorship BdV conceived and designed the study and analysed the data. BdV, RM, AEB, PK collected data. BdV and RM wrote the first draft of the manuscript. All authors critically revised and contributed to the manuscript for publication. We certify that all authors are responsible for the content of the article and have read and approved the final version.
Details of ethics approval This study underwent institutional board review and received ethics approval from the Sydney Local Health District (RPAH Zone) ethics committee (Protocol No X16-0466) on April 17 2017.