Evidence of overuse? Patterns of obstetric interventions during labour and birth among Australian mothers

There is global concern for the overuse of obstetric interventions during labour and birth. Of particular concern is the increasing amount of mothers and babies experiencing morbidity and mortality associated with caesarean section compared to vaginal birth. In high-income settings, emerging evidence suggests that overuse of obstetric intervention is more prevalent among wealthier mothers with no medical need of it. In Australia, the rates of caesarean section and other obstetric interventions are rising. These rising rates of intervention have been mirrored by a decreasing rate of unassisted non-instrumental vaginal deliveries. In the context of rising global concern about rising caesarean section rates and the known health effects of caesarean section on mothers and children, we aim to better characterise the use of obstetric intervention in the state of Queensland, Australia by examining the characteristics of mothers receiving obstetric intervention. Identifying whether there is overuse of obstetric interventions within a population is critical to improving the quality, value and appropriateness of maternity care.

The association between demographic characteristics (at birth) and birth delivery type were compared with chi-square. The percentage of mothers based on their socioeconomic characteristics were reported and differences in percentages of obstetric interventions were compared. Multivariate analysis was undertaken using multiple logistic regression to assess the likelihood of receiving obstetric intervention and having a vaginal (non-instrumental) delivery after accounting for key clinical characteristics.

Indigenous mothers, mothers in major cities and mothers in the wealthiest quintile all had higher percentages of all obstetric interventions and had the lowest percentages of unassisted (non-instrumental) vaginal births. These differences remained even after adjusting for other key sociodemographic and clinical characteristics.

Differences in obstetric practice exist between economic, ethnic and geographical groups of mothers that are not attributable to medical or lifestyle risk factors. These differences may reflect health system, organisational and structural conditions and therefore, a better understanding of the non-clinical factors that influence the supply and demand of obstetric interventions is required.