Background: The determinants of Queensland's rising caesarean section (CS) rate remain poorly understood because of the historical absence of standard classification methods.
Aims: We applied the Robson Ten Group Classification System (RTGCS) to population-based data to identify the main contributors to Queensland's rising CS rate.
Method: The RTGCS was applied retrospectively to the Queensland Perinatal Data Collection. CS rates were described for all ten RTGCS groups using data from 2006. Trends were evaluated using data for the years 1997-2006. Public and private sector patients were evaluated separately.
Results: In Queensland, in 2006, CS rates were 26.9 and 48.0% among public and private sector patients, respectively. Multiparous women with a previous caesarean birth (Group 5) made the greatest contribution to the CS rate in both sectors, followed by nulliparous women who had labour induced or were delivered by CS prior to the onset of labour (Group 2) and nulliparous women in spontaneous labour (Group 1). CS rates have risen in all RTGCS groups between 1997 and 2006. The trend was pronounced among multiparous women with a previous caesarean delivery (Group 5), among women with multiple pregnancies (Group 8) and among nulliparous women who had labour induced or were delivered by CS prior to the onset of labour (Group 2).
Conclusions: The CS rate in Queensland in 2006 was higher than in any other Australian state. The increase in Queensland's CS rates can be attributed to both the rising number of primary caesarean births and the rising number of repeat caesareans.